Mr. Justice Brennan

delivered the opinion of the Court.

Petitioner was convicted in Los Angeles Municipal Court of the criminal offense of driving an automobile while under the influence of intoxicating liquor.1 He had been arrested at a hospital while receiving treatment for injuries suffered in an accident involving the automobile that he had apparently been driving.2 At the direction of a police officer, a blood sample was then withdrawn from petitioner’s body by a physician at the hospital. *759The chemical analysis of this sample revealed a percent by weight of alcohol in his blood at the time of the offense which indicated intoxication, and the report of this analysis was admitted in evidence at the trial. Petitioner objected to receipt of this evidence of the analysis on the ground that the blood had been withdrawn despite his refusal, on the advice of his counsel, to consent to the test. He contended that in that circumstance the withdrawal of the blood and the admission of the analysis in evidence denied him due process of law under the Fourteenth Amendment, as well as specific guarantees of the Bill of Rights secured against the States by that Amendment: his privilege against self-incrimination under the Fifth Amendment; his right to counsel under the Sixth Amendment; and his right not to be subjected to unreasonable searches and seizures in violation of the Fourth Amendment. The Appellate Department of the California Superior Court rejected these contentions and affirmed the conviction.3 In view of constitutional decisions since we last considered these issues in Breithaupt v. Abram, 352 U. S. 432—see Escobedo v. Illinois, 378 U. S. 478; Malloy v. Hogan, 378 U. S. 1, and Mapp v. Ohio, 367 U. S. 643—we granted certiorari. 382 U. S. 971. We affirm.

I.

The Due Process Clause Claim.

Breithaupt was also a case in which police officers caused blood to be withdrawn from the driver of an automobile involved in an accident, and in which there was ample justification for the officer’s conclusion that the driver was under the influence of alcohol. There, as here, the extraction was made by a physician in a simple, medically acceptable manner in a hospital environment. *760There, however, the driver was unconscious at the time the blood was withdrawn and hence had no opportunity to object to the procedure. We affirmed the conviction there resulting from the use of the test in evidence, holding that under such circumstances the withdrawal did not offend “that ‘sense of justice’ of which we spoke in Rochin v. California, 342 U. S. 165.” 352 U. S., at 435. Breithaupt thus requires the rejection of petitioner’s due process argument, and nothing in the circumstances of this case4 or in supervening events persuades us that this aspect of Breithaupt should be overruled.

II.

The Privilege Against Self-Incrimination Claim.

Breithaupt summarily rejected an argument that the withdrawal of blood and the admission of the analysis report involved in that state case violated the Fifth Amendment privilege of any person not to “be compelled in any criminal case to be a witness against himself,” citing Twining v. New Jersey, 211 U. S. 78. But that case, holding that the protections of the Fourteenth Amendment do not embrace this Fifth Amendment privilege, has been succeeded by Malloy v. Hogan, 378 U. S. 1, 8. We there held that “[t]he Fourteenth Amendment secures against state invasion the same privilege that the Fifth Amendment guarantees against federal infringement — the right of a person to remain silent unless he chooses to speak in the unfettered exercise of his own will, *761and to suffer no penalty ... for such silence.” We therefore must now decide whether the withdrawal of the blood and admission in evidence of the analysis involved in this case violated petitioner’s privilege. We hold that the privilege protects an accused only from being compelled to testify against himself, or otherwise provide the State with evidence of a testimonial or communicative nature,5 and that the withdrawal of blood and use of the analysis in question in this case did not involve compulsion to these ends.

It could not be denied that in requiring petitioner to submit to the withdrawal and chemical analysis of his blood the State compelled him to submit to an attempt to discover evidence that might be used to prosecute him for a criminal offense. He submitted only after the police officer rejected his objection and directed the physician to proceed. The officer’s direction to the physician to administer the test over petitioner’s objection constituted compulsion for the purposes of the privilege. The critical question, then, is whether petitioner was thus compelled “to be a witness against himself.” 6

*762If the scope of the privilege coincided with the complex of values it helps to protect, we might be obliged to conclude that the privilege was violated. In Miranda v. Arizona, ante, at 460, the Court said of the interests protected by the privilege: “All these policies point to one overriding thought: the constitutional foundation underlying the priyilege is the respect a government — state or federal — must accord to the dignity and integrity of its citizens. To maintain a ‘fair state-individual balance/ to require the government ‘to shoulder the entire load’. . . to respect the inviolability of the human personality, our accusatory system of criminal justice demands that the government seeking to punish an individual produce the evidence against him by its own independent labors, rather than by the cruel, simple expedient of compelling it from his own mouth.” The withdrawal of blood necessarily involves puncturing the skin for extraction, and the percent by weight of alcohol in that blood, as established by chemical analysis, is evidence of criminal guilt. Compelled submission fails on one view to respect the “inviolability of the human personality.” Moreover, since it enables the State to rely on evidence forced from the accused, the compulsion violates at least one meaning of the requirement that the State procure the evidence against an accused “by its own independent labors.”

As the passage in Miranda implicitly recognizes, however, the privilege has never been given the full scope which the values it helps to protect suggest. History *763and a long line of authorities in lower courts have consistently limited its protection to situations in which the State seeks to submerge those values by obtaining the evidence against an accused through “the cruel, simple expedient of compelling it from his own mouth. ... In sum, the privilege is fulfilled only when the person is guaranteed the right ‘to remain silent unless he chooses to speak in the unfettered exercise of his own will.’ ” Ibid. The leading case in this Court is Holt v. United States, 218 U. S. 245. There the question was whether evidence was admissible that the accused, prior to trial and over his protest, put on a blouse that fitted him. It was contended that compelling the accused to submit to the demand that he model the blouse violated the privilege. Mr. Justice Holmes, speaking for the Court, rejected the argument as “based upon an extravagant extension of the Fifth Amendment,” and went on to say: “[T]he prohibition of compelling a man in a criminal court to be witness against himself is a prohibition of the use of physical or moral compulsion to extort communications from him, not an exclusion of his body as evidence when it may be material. The objection in principle would forbid a jury to look at a prisoner and compare his features with a photograph in proof.” 218 U. S., at 252-253.7

It is clear that the protection of the privilege reaches an accused’s communications, whatever form they might *764take, and the compulsion of responses which are also communications, for example, compliance with a subpoena to produce one’s papers. Boyd v. United States, 116 U. S. 616. On the other hand, both federal and state courts have usually held that it offers no protection against compulsion to submit to fingerprinting, photographing, or measurements, to write or speak for identification, to appear in court, to stand, to assume a stance, to walk, or to make a particular gesture.8 The distinction which has emerged, often expressed in different ways, is that the privilege is a bar against compelling “communications” or “testimony,” but that compulsion which makes a suspect or accused the source of “real or physical evidence” does not violate it.

Although we agree that this distinction is a helpful framework for analysis, we are not to be understood to agree with past applications in all instances. There will be many cases in which such a distinction is not readily drawn. Some tests seemingly directed to obtain “physical evidence,” for example, lie detector tests measuring changes in body function during interrogation, may actually be directed to eliciting responses which are essentially testimonial. To compel a person to submit to testing in which an effort will be made to determine his guilt or innocence on the basis of physiological responses, whether willed or not, is to evoke the spirit and history of the Fifth Amendment. Such situations call to mind the principle that the protection of the privilege “is as broad as the mischief against which it seeks to guard,” Counselman v. Hitchcock, 142 U. S. 547, 562.

*765In the present case, however, no such problem of application is presented. Not even a shadow of testimonial compulsion upon or enforced communication by the accused was involved either in the extraction or in the chemical analysis. Petitioner’s testimonial capacities were in no way implicated; indeed, his participation, except as a donor, was irrelevant to the results of the test, which depend on chemical analysis and on that alone.9 Since the blood test evidence, although an incriminating product of compulsion, was neither petitioner’s testimony nor evidence relating to some communicative act or writing by the petitioner, it was not inadmissible on privilege grounds.

III.

The Right to Counsel Claim.

This conclusion also answers petitioner’s claim that, in compelling him to submit to the test in face of the fact that his objection was made on the advice of counsel, *766he was denied his Sixth Amendment right to the assistance of counsel. Since petitioner was not entitled to assert the privilege, he has no greater right because counsel erroneously advised him that he could assert it. His claim is strictly limited to the failure of the police to respect his wish, reinforced by counsel’s advice, to be left inviolate. No issue of counsel’s ability to assist petitioner in respect of any rights he did possess is presented. The limited claim thus made must be rejected.

IV.

The Search and Seizure Claim.

In Breithaupt, as here, it was also contended that the chemical analysis should be excluded from evidence as the product of an unlawful search and seizure in violation of the Fourth and Fourteenth Amendments. The Court did not decide whether the extraction of blood in that case was unlawful, but rejected the claim on the basis of Wolf v. Colorado, 338 U. S. 25. That case had held that the Constitution did not require, in state prosecutions for state crimes, the exclusion of evidence obtained in violation of the Fourth Amendment’s provisions. We have since overruled Wolf in that respect, holding in Mapp v. Ohio, 367 U. S. 643, that the exclusionary rule adopted for federal prosecutions in Weeks v. United States, 232 U. S. 383, must also be applied in criminal prosecutions in state courts. The question is squarely presented therefore, whether the chemical anal*767ysis introduced in evidence in this case should have been excluded as the product of an unconstitutional search and seizure.

The overriding function qf the Fourth Amendment is to protect personal privacy and dignity against unwarranted intrusion by the State. In Wolf we recognized “[t]he security of one’s privacy against arbitrary intrusion by the police” as being “at the core of the Fourth Amendment” and “basic to a free society.” 338 U. S., at 27. We reaffirmed that broad view of the Amendment’s purpose in applying the federal exclusionary rule to the States in Mapp.

The values protected by the Fourth Amendment thus substantially overlap those the Fifth Amendment helps to protect. History and precedent have required that we today reject the claim that the Self-Incrimination Clause of the Fifth Amendment requires the human body in all circumstances to be held inviolate against state expeditions seeking evidence of crime. But if compulsory administration of a blood test does not implicate the Fifth Amendment, it plainly involves the broadly conceived reach of a search and seizure under the Fourth Amendment. That Amendment expressly provides that “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated . . . .” (Emphasis added.) It could not reasonably be argued, and indeed respondent does not argue, that the administration of the blood test in this case was free of the constraints of the Fourth Amendment. Such testing procedures plainly constitute searches of “persons,” and depend antecedently upon seizures of “persons,” within the meaning of that Amendment.

Because we are dealing with intrusions into the human body rather than with state interferences with property relationships or private papers — “houses, papers, and *768effects” — we write on a clean slate. Limitations on the kinds of property which may be seized under warrant,10 as distinct from the procedures for search and the permissible scope of search,11 are not instructive in this context. We begin with the assumption that once the privilege against self-incrimination has been found not to bar compelled intrusions into the body for blood to be analyzed for alcohol content, the Fourth Amendment’s proper function is to constrain, not against all intrusions as such, but against intrusions which are not justified in the circumstances, or which are made in an improper manner. In other words, the questions we must decide in this case are whether the police were justified in requiring petitioner to submit to the blood test, and whether the means and procedures employed in taking his blood respected relevant Fourth Amendment standards of reasonableness.

In this case, as will often be true when charges of driving under the influence of alcohol are pressed, these questions arise in the context of an arrest made by an officer without a warrant. Here, there was plainly probable cause for the officer to arrest petitioner and charge him with driving an automobile while under the influence of intoxicating liquor.12 The police officer who arrived *769at the scene shortly after the accident smelled liquor on petitioner’s breath, and testified that petitioner’s eyes were “bloodshot, watery, sort of a glassy appearance.” The officer saw petitioner again at the hospital, within two hours of the accident. There he noticed similar symptoms of drunkenness. He thereupon informed petitioner “that he was under arrest and that he was entitled to the services of an attorney, and that he could remain silent, and that anything that he told me would be used against him in evidence.”

While early cases suggest that there is an unrestricted “right on the part of the Government, always recognized under English and American law, to search the person of the accused when legally arrested to discover and seize the fruits or evidences of crime,” Weeks v. United States, 232 U. S. 383, 392; People v. Chiagles, 237 N. Y. 193, 142 N. E. 583 (1923) (Cardozo, J.), the mere fact of a lawful arrest does not end our inquiry. The suggestion of these cases apparently rests on two factors — first, there may be more immediate danger of concealed weapons or of destruction of evidence under the direct control of the accused, United States v. Rabinowitz, 339 U. S. 56, 72-73 (Frankfurter, J., dissenting); second, once a search of the arrested person for weapons is permitted, it would be both impractical and unnecessary to enforcement of the Fourth Amendment’s purpose to attempt to confine the search to those objects alone. People v. Chiagles, 237 N. Y., at 197-198, 142 N. E., at 584. Whatever the validity of these considerations in general, they have little applicability with respect to searches involving intrusions beyond the body’s surface. The interests in *770human dignity and privacy which the Fourth Amendment protects forbid any such intrusions on the mere chance that desired evidence might be obtained. In the absence of a clear indication that in fact such evidence will be found, these fundamental human interests require law officers to suffer the risk that such evidence may disappear unless there is an immediate search.

Although the facts which established probable cause to arrest in this case also suggested the required relevance and likely success of a test of petitioner’s blood for alcohol, the question remains whether the arresting officer was permitted to draw these inferences himself, or was required instead to procure a warrant before proceeding with the test. Search warrants are ordinarily required for searches of dwellings, and, absent an emergency, no less could be required where intrusions into the human body are concerned. The requirement that a warrant be obtained is a requirement that the inferences to support the search “be drawn by a neutral and detached magistrate instead of being judged by the officer engaged in the often competitive enterprise of ferreting out crime.” Johnson v. United States, 333 U. S. 10, 13-14; see also Aguilar v. Texas, 378 U. S. 108, 110-111. The importance of informed, detached and deliberate determinations of the issue whether or not to invade another’s body in search of evidence of guilt is indisputable and great.

The officer in the present case, however, might reasonably have believed that he was confronted with an emergency, in which the delay necessary to obtain a warrant, under the circumstances, threatened “the destruction of evidence,” Preston v. United States, 376 U. S. 364, 367. We are told that the percentage of alcohol in the blood begins to diminish shortly after drinking stops, as the body functions to eliminate it from the system. Particularly in a case such as this, where time had *771to be taken to bring the accused to a hospital and to investigate the scene of the accident, there was no time to seek out a magistrate and secure a warrant. Given these special facts, we conclude that the attempt to secure evidence of blood-alcohol content in this case was an appropriate incident to petitioner’s arrest.

Similarly, we are satisfied that the test chosen to measure petitioner’s blood-alcohol level was a reasonable one. Extraction of blood samples for testing is a highly effective means of determining the degree to which a person is under the influence of alcohol. See Breithaupt v. Abram, 352 U. S., at 436, n. 3. Such tests are a commonplace in these days of periodic physical examinations 13 and experience with them teaches that the quantity of blood extracted is minimal, and that for most people the procedure involves virtually no risk, trauma, or pain. Petitioner is not one of the few who on grounds of fear, concern for health, or religious scruple might prefer some other means of testing, such as the “breathalyzer” test petitioner refused, see n. 9, supra. We need not decide whether such wishes would have to be respected.14

Finally, the record shows that the test was performed in a reasonable manner. Petitioner’s blood was taken by a physician in a hospital environment according to accepted medical practices. We are thus not presented with the serious questions which would arise if a search involving use of a medical technique, even of the most *772rudimentary sort, were made by other than medical personnel or in other than a medical environment — for example, if it were administered by police in the privacy of the stationhouse. To tolerate searches under these conditions might be to invite an unjustified element of personal risk of infection and pain.

We thus conclude that the present record shows no violation of petitioner’s right under the Fourth and Fourteenth Amendments to be free of unreasonable searches and seizures. It bears repeating, however, that we reach this judgment only on the facts of the present record. The integrity of an individual’s person is a cherished value of our society. That we today hold that the Constitution does not forbid the States minor intrusions into an individual’s body under stringently limited conditions in no way indicates that it permits more substantial intrusions, or intrusions under other conditions.

Affirmed.

Mr. Justice Harlan,

whom Mr. Justice Stewart joins,

concurring.

In joining the Court’s opinion I desire to add the following comment. While agreeing with the Court that the taking of this blood test involved no testimonial compulsion, I would go further and hold that apart from this consideration the case in no way implicates the Fifth Amendment. Cf. my dissenting opinion and that of Mr. Justice White in Miranda v. Arizona, ante, pp. 504, 526.

Mr. Chief Justice Warren,

dissenting.

While there are other important constitutional issues in this case, I believe it is sufficient for me to reiterate my dissenting opinion in Breithaupt v. Abram, 352 U. S. 432, 440, as the basis on which to reverse this conviction.

*773Mr. Justice Black

with whom Mr. Justice Douglas joins,

dissenting.

I would reverse petitioner’s conviction. I agree with the Court that the Fourteenth Amendment made applicable to the States the Fifth Amendment’s provision that “No person . . . shall be compelled in any criminal case to be a witness against himself . . . .” But I disagree with the Court’s holding that California did not violate petitioner’s constitutional right against self-incrimination when it compelled him, against his will, to allow a doctor to puncture his blood vessels in order to extract a sample of blood and analyze it for alcoholic content, and then used that analysis as evidence to convict petitioner of a crime.

The Court admits that “the State compelled [petitioner] to submit to an attempt to discover evidence [in his blood] that might be [and was] used to prosecute him for a criminal offense.” To reach the conclusion that compelling a person to give his blood to help the State convict him is not equivalent to compelling him to be a witness against himself strikes me as quite an extraordinary feat. The Court, however, overcomes what had seemed to me to be an insuperable obstacle to its conclusion by holding that

“. . . the privilege protects an accused only from being compelled to testify against himself, or otherwise provide the State with evidence of a testimonial or communicative nature, and that the withdrawal of blood and use of the analysis in question in this case did not involve compulsion to these ends.” (Footnote omitted.)

I cannot agree that this distinction and reasoning of the Court justify denying petitioner his Bill of Rights’ guarantee that he must not be compelled to be a witness against himself.

*774In the first place it seems to me that the compulsory extraction of petitioner’s blood for analysis so that the person who analyzed it could give evidence to convict him had both a “testimonial” and a “communicative nature.” The sole purpose of this project which proved to be successful was to obtain “testimony” from some person to prove that petitioner had alcohol in his blood at the time he was arrested. And the purpose of the project was certainly “communicative” in that the analysis of the blood was to supply information to enable a witness to communicate to the court and jury that petitioner was more or less drunk.

I think it unfortunate that the Court rests so heavily for its very restrictive reading of the Fifth Amendment’s privilege against self-incrimination on the words “testimonial” and “communicative.” These words are not models of clarity and precision as the Court’s rather labored explication shows. Nor can the Court, so far as I know, find precedent in the former opinions of this Court for using these particular words to limit the scope of the Fifth Amendment’s protection. There is a scholarly precedent, however, in the late Professor Wigmore’s learned treatise on evidence. He used “testimonial” which, according to the latest edition of his treatise revised by McNaughton, means “communicative” (8 Wigmore, Evidence § 2263 (McNaughton rev. 1961), p. 378), as a key word in his vigorous and extensive campaign designed to keep the privilege against self-incrimination “within limits the strictest possible.” 8 Wigmore, Evidence § 2251 (3d ed. 1940), p. 318. Though my admiration for Professor Wigmore’s scholarship is great, I regret to see the word he used to narrow the Fifth Amendment’s protection play such a major part in any of this Court’s opinions.

I am happy that the Court itself refuses to follow Professor Wigmore’s implication that the Fifth Amend*775ment goes no further than to bar the use of forced self-incriminating statements coming from a “person’s own lips.” It concedes, as it must so long as Boyd v. United States, 116 U. S. 616, stands, that the Fifth Amendment bars a State from compelling a person to produce papers he has that might tend to incriminate him. It is a strange hierarchy of values that allows the State to extract a human being’s blood to convict him of a crime because of the blood’s content but proscribes compelled production of his lifeless papers. Certainly there could be few papers that would have any more “testimonial” value to convict a man of drunken driving than would an analysis of the alcoholic content of a human being’s blood introduced in evidence at a trial for driving while under the influence of alcohol. In such a situation blood, of course, is not oral testimony given by an accused but it can certainly “communicate” to a court and jury the fact of guilt.

The Court itself, at page 764, expresses its own doubts, if not fears, of its own shadowy distinction between compelling “physical evidence” like blood which it holds does not amount to compelled self-incrimination, and “eliciting responses which are essentially testimonial.” And in explanation of its fears the Court goes on to warn that

“To compel a person to submit to testing [by lie detectors for example] in which an effort will be made to determine his guilt or innocence on the basis of physiological responses, whether willed or not, is to evoke the spirit and history of the Fifth Amendment. Such situations call to mind the principle that the protection of the privilege ‘is as broad as the mischief against which it seeks to guard.’ Counselman v. Hitchcock, 142 U. S. 547, 562.”

A basic error in the Court’s holding and opinion is its failure to give the Fifth Amendment’s protection against *776compulsory self-incrimination the broad and liberal construction that Counselman and other opinions of this Court have declared it ought to have.

The liberal construction given the Bill of Rights’ guarantee in Boyd v. United States, supra, which Professor Wigmore criticized severely, see 8 Wigmore, Evidence, § 2264 (3d ed. 1940), pp. 366-373, makes that one among the greatest constitutional decisions of this Court. In that case, at 634-635, all the members of the Court decided that civil suits for penalties and forfeitures incurred for commission of offenses against the law,

“. . . are within the reason of criminal proceedings for all the purposes of . . . that portion of the Fifth Amendment which declares that no person shall be compelled in any criminal case to be a witness against himself; . . . within the meaning of the Fifth Amendment to the Constitution . . . *

Obviously the Court’s interpretation was not completely supported by the literal language of the Fifth Amendment. Recognizing this, the Court announced a rule of constitutional interpretation that has been generally followed ever since, particularly in judicial construction of Bill of Rights guarantees:

“A close and literal construction [of constitutional provisions for the security of persons and property] deprives them of half their efficacy, and leads to gradual depreciation of the right, as if it consisted more in sound than in substance. It is the duty of courts to be watchful for the constitutional rights of the citizen, and against any stealthy encroach*777ments thereon.” Boyd v. United States, supra, at 635.

The Court went on to say, at 637, that to require “an owner to produce his private books and papers, in order to prove his breach of the laws, and thus to establish the forfeiture of his property, is surely compelling him to furnish evidence against himself.” The Court today departs from the teachings of Boyd. Petitioner Schmerber has undoubtedly been compelled to give his blood “to furnish evidence against himself,” yet the Court holds that this is not forbidden by the Fifth Amendment. With all deference I must say that the Court here gives the Bill of Rights’ safeguard against compulsory self-incrimination a construction that would generally be considered too narrow and technical even in the interpretation of an ordinary commercial contract.

The Court apparently, for a reason I cannot understand, finds some comfort for its narrow construction of the Fifth Amendment in this Court’s decision in Miranda v. Arizona, ante, p. 436. I find nothing whatever in the majority opinion in that case which either directly or indirectly supports the holding in this case. In fact I think the interpretive constitutional philosophy used in Miranda, unlike that used in this case, gives the Fifth Amendment’s prohibition against compelled self-incrimination a broad and liberal construction in line with the wholesome admonitions in the Boyd case. The closing sentence in the Fifth Amendment section of the Court’s opinion in the present case is enough by itself, I think, to expose the unsoundness of what the Court here holds. That sentence reads: *778How can it reasonably be doubted that the blood test evidence was not in all respects the actual equivalent of “testimony” taken from petitioner when the result of the test was offered as testimony, was considered by the jury as testimony, and the jury’s verdict of guilt rests in part on that testimony? The refined, subtle reasoning and balancing process used here to narrow the scope of the Bill of Rights’ safeguard against self-incrimination provides a handy instrument for further narrowing of that constitutional protection, as well as others, in the future. Believing with the Framers that these constitutional safeguards broadly construed by independent tribunals of justice provide our best hope for keeping our people free from governmental oppression, I deeply regret the Court’s holding. For the foregoing reasons as well as those set out in concurring opinions of Black and Douglas, JJ., in Rochin v. California, 342 U. S. 165, 174, 177, and my concurring opinion in Mapp v. Ohio, 367 U. S. 643, 661, and the dissenting opinions in Breithaupt v. Abram, 352 U. S. 432, 440, 442, I dissent from the Court’s holding and opinion in this case.

*777“Since the blood test evidence, although an incriminating product of compulsion, was neither petitioner’s testimony nor evidence relating to some communicative act or writing by the petitioner, it was not inadmissible on privilege grounds.”

*778Mr. Justice Douglas,

dissenting.

I adhere to the views of The Chief Justice in his dissent in Breithaupt v. Abram, 352 U. S. 432, 440, and to the views I stated in my dissent in that case (id., 442) and add only a word.

We are dealing with the right of privacy which, since the Breithaupt case, we have held to be within the penumbra of some specific guarantees of the Bill of Rights. Griswold v. Connecticut, 381 U. S. 479. Thus, the Fifth Amendment marks “a zone of privacy” which the Government may not force a person to surrender. Id., 484. Likewise the Fourth Amendment recognizes that right when it guarantees the right of the people to be *779secure “in their persons.” Ibid. No clearer invasion of this right of privacy can be imagined than forcible bloodletting of the kind involved here.

Me. Justice Foetas,

dissenting.

I would reverse. In my view, petitioner’s privilege against self-incrimination applies. I would add that, under the Due Process Clause, the State, in its role as prosecutor, has no right to extract blood from an accused or anyone else, over his protest. As prosecutor, the State has no right to commit any kind of violence upon the person, or to utilize the results of such a tort, and the extraction of blood, over protest, is an act of violence. Cf. Chief Justice Warren’s dissenting opinion in Breithaupt v. Abram, 352 U. S. 432, 440.

Mr. Chief Justice Warren

delivered the opinion of the Court.

This case presents serious questions concerning the role of the Fourth Amendment in the confrontation on the street between the citizen and the policeman investigating suspicious circumstances.

Petitioner Terry was convicted of carrying a concealed weapon and sentenced to the statutorily prescribed term of one to three years in the penitentiary.1 Following *5the denial of a pretrial motion to suppress, the prosecution introduced in evidence two revolvers and a number of bullets seized from Terry and a codefendant, Richard Chilton,2 by Cleveland Police Detective Martin McFadden. At the hearing on the motion to suppress this evidence, Officer McFadden testified that while he was patrolling in plain clothes in downtown Cleveland at approximately 2:30 in the afternoon of October 31, 1963, his attention was attracted by two men, Chilton and Terry, standing on the corner of Huron Road and Euclid Avenue. He had never seen the two men before, and he was unable to say precisely what first drew his eye to them. However, he testified that he had been a policeman for 39 years and a detective for 35 and that he had been assigned to patrol this vicinity of downtown Cleveland for shoplifters and pickpockets for 30 years. He explained that he had developed routine habits of observation over the years and that he would “stand and watch people or walk and watch people at many intervals of the day.” He added: “Now, in this case when I looked over they didn’t look right to me at the time.”

His interest aroused, Officer McFadden took up a post of observation in the entrance to a store 300 to 400 feet *6away from the two men. “I get more purpose to watch them when I seen their movements,” he testified. He saw one of the men leave the other one and walk southwest on Huron Road, past some stores. The man paused for a moment and looked in a store window, then walked on a short distance, turned around and walked back toward the corner, pausing once again to look in the same store window. He rejoined his companion at the comer, and the two conferred briefly. Then the second man went through the same series of motions, strolling down Huron Road, looking in the same window, walking on a short distance, turning back, peering in the store window again, and returning to confer with the first man at the corner. The two men repeated this ritual alternately between five and six times apiece — in all, roughly a dozen trips. At one point, while the two were standing together on the corner, a third man approached them and engaged them briefly in conversation. This man then left the two others and walked west on Euclid Avenue. Chilton and Terry resumed their measured pacing, peering, and conferring. After this had gone on for 10 to 12 minutes, the two men walked off together, heading west on Euclid Avenue, following the path taken earlier by the third man.

By this time Officer McFadden had become thoroughly suspicious. He testified that after observing their elaborately casual and oft-repeated reconnaissance of the store window on Huron Road, he suspected the two men of “casing a job, a stick-up,” and that he considered it his duty as a police officer to investigate further. He added that he feared “they may have a gun.” Thus, Officer McEadden followed Chilton and Terry and saw them stop in front of Zucker’s store to talk to the same man who had conferred with them earlier on the street corner. Deciding that the situation was ripe for direct action, Officer McFadden approached the three men, iden*7tified himself as a police officer and asked for their names. At this point his knowledge was confined to what he had observed. He was not acquainted with any of the three men by name or by sight, and he had received no information concerning them from any other source. When the men “mumbled something” in response to his inquiries, Officer McFadden grabbed petitioner Terry, spun him around so that they were facing the other two, with Terry between McFadden and the others, and patted down the outside of his clothing. In the left breast pocket of Terry’s overcoat Officer McFadden felt a pistol. He reached inside the overcoat pocket, but was unable to remove the gun. At this point, keeping Terry between himself and the others, the officer ordered all three men to enter Zucker’s store. As they went in, he removed Terry’s overcoat completely, removed a .38-caliber revolver from the pocket and ordered all three men to face the wall with their hands raised. Officer McFadden proceeded to pat down the outer clothing of Chilton and the third man, Katz. He discovered another revolver in the outer pocket of Chilton’s overcoat, but no weapons were found on Katz. The officer testified that he only patted the men down to see whether they had weapons, and that he did not put his hands beneath the outer garments of either Terry or Chilton until he felt their guns. So far as appears from the record, he never placed his hands beneath Katz’ outer garments. Officer McFadden seized Chilton’s gun, asked the proprietor of the store to call a police wagon, and took all three men to the station, where Chilton and Terry were formally charged with carrying concealed weapons.

On the motion to suppress the guns the prosecution took the position that they had been seized following a search incident to a lawful arrest. The trial court rejected this theory, stating that it “would be stretching the facts beyond reasonable comprehension” to find that Officer *8McFadden had had probable cause to arrest the men before he patted them down for weapons. However, the court denied the defendants’ motion on the ground that Officer McFadden, on the basis of his experience, “had reasonable cause to believe . . . that the defendants were conducting themselves suspiciously, and some interrogation should be made of their action.” Purely for his own protection, the court held, the officer had the right to pat down the outer clothing of these men, who he had reasonable cause to believe might be armed. The court distinguished between an investigatory “stop” and an arrest, and between a “frisk” of the outer clothing for weapons and a full-blown search for evidence of crime. The frisk, it held, was essential to the proper performance of the officer’s investigatory duties, for without it “the answer to the police officer may be a bullet, and a loaded pistol discovered during the frisk is admissible.”

After the court denied their motion to suppress, Chilton and Terry waived jury trial and pleaded not guilty. The court adjudged them guilty, and the Court of Appeals for the Eighth Judicial District, Cuyahoga County, affirmed. State v. Terry, 5 Ohio App. 2d 122, 214 N. E. 2d 114 (1966). The Supreme Court of Ohio dismissed their appeal on the ground that no “substantial constitutional question” was involved. We granted certiorari, 387 U. S. 929 (1967), to determine whether the admission of the revolvers in evidence violated petitioner’s rights under the Fourth Amendment, made applicable to the States by the Fourteenth. Mapp v. Ohio, 367 U. S. 643 (1961). We affirm the conviction.

I.

The Fourth Amendment provides that “the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated . . . .” This inestimable right of *9personal security belongs as much to the citizen on the streets of our cities as to the homeowner closeted in his study to dispose of his secret affairs. For, as this Court has always recognized,

“No right is held more sacred, or is more carefully guarded, by the common law, than the right of every individual to the possession and control of his own person, free from all restraint or interference of others, unless by clear and unquestionable authority of law.” Union Pac. R. Co. v. Botsford, 141 U. S. 250, 251 (1891).

We have recently held that “the Fourth Amendment protects people, not places,” Katz v. United States, 389 U. S. 347, 351 (1967), and wherever an individual may harbor a reasonable “expectation of privacy,” id., at 361 (Mr. Justice Harlan, concurring), he is entitled to be free from unreasonable governmental intrusion. Of course, the specific content and incidents of this right must be shaped by the context in which it is asserted. For “what the Constitution forbids is not all searches and seizures, but unreasonable searches and seizures.” Elkins v. United States, 364 U. S. 206, 222 (1960). Unquestionably petitioner was entitled to the protection of the Fourth Amendment as he walked down the street in Cleveland. Beck v. Ohio, 379 U. S. 89 (1964); Rios v. United States, 364 U. S. 253 (1960); Henry v. United States, 361 U. S. 98 (1959); United States v. Di Re, 332 U. S. 581 (1948); Carroll v. United States, 267 U. S. 132 (1925). The question is whether in all the circumstances of this on-the-street encounter, his right to personal security was violated by an unreasonable search and seizure.

We would be less than candid if we did not acknowledge that this question thrusts to the fore difficult and troublesome issues regarding a sensitive area of police activity — issues which have never before been squarely *10presented to this Court. Reflective of the tensions involved are the practical and constitutional arguments pressed with great vigor on both sides of the public debate over the power of the police to “stop and frisk”— as it is sometimes euphemistically termed — suspicious persons.

On the one hand, it is frequently argued that in dealing with the rapidly unfolding and often dangerous situations on city streets the police are in need of an escalating set of flexible responses, graduated in relation to the amount of information they possess. For this purpose it is urged that distinctions should be made between a “stop” and an “arrest” (or a “seizure” of a person), and between a “frisk” and a “search.” 3 Thus, it is argued, the police should be allowed to “stop” a person and detain him briefly for questioning upon suspicion that he may be connected with criminal activity. Upon suspicion that the person may be armed, the police should have the power to “frisk” him for weapons. If the “stop” and the “frisk” give rise to probable cause to believe that the suspect has committed a crime, then the police should be empowered to make a formal “arrest,” and a full incident “search” of the person. This scheme is justified in part upon the notion that a “stop” and a “frisk” amount to a mere “minor inconvenience and petty indignity,” 4 which can properly be imposed upon the *11citizen in the interest of effective law enforcement on the basis of a police officer's suspicion.5

On the other side the argument is made that the authority of the police must be strictly circumscribed by the law of arrest and search as it has developed to date in the traditional jurisprudence of the Fourth Amendment.6 It is contended with some force that there is not — and cannot be — a variety of police activity which does not depend solely upon the voluntary cooperation of the citizen and yet which stops short of an arrest based upon probable cause to make such an arrest. The heart of the Fourth Amendment, the argument runs, is a severe requirement of specific justification for any intrusion upon protected personal security, coupled with á highly developed system of judicial controls to enforce upon the agents of the State the commands of the Constitution. Acquiescence by the courts in the compulsion inherent *12in the field interrogation practices at issue here, it is urged, would constitute an abdication of judicial control over, and indeed an encouragement of, substantial interference with liberty and personal security by police officers whose judgment is necessarily colored by their primary involvement in “the often competitive enterprise of ferreting out crime.” Johnson v. United States, 333 U. S. 10, 14 (1948). This, it is argued, can only serve to exacerbate police-community tensions in the crowded centers of our Nation’s cities.7

In this context we approach the issues in this case mindful of the limitations of the judicial function in controlling the myriad daily situations in which policemen and citizens confront each other on the street. The State has characterized the issue here as “the right of a police officer ... to make an on-the-street stop, interrogate and pat down for weapons (known in street vernacular as ‘stop and frisk’).”8 But this is only partly accurate. For the issue is not the abstract propriety of the police conduct, but the admissibility against petitioner of the evidence uncovered by the search and seizure. Ever since its inception, the rule excluding evidence seized in violation of the Fourth Amendment has been recognized as a principal mode of discouraging lawless police conduct. See Weeks v. United States, 232 U. S. 383, 391-393 (1914). Thus its major thrust is a deterrent one, see Linkletter v. Walker, 381 U. S. 618, 629-635 (1965), and experience has taught that it is the only effective deterrent to police misconduct in the criminal context, and that without it the constitutional guarantee against unreasonable searches and seizures would be a mere “form of words.” Mapp v. Ohio, 367 U. S. 643, 655 (1961). The rule also serves another vital function — “the imperative of judicial integrity.” Elkins *13v. United States, 364 U. S. 206, 222 (1960). Courts which sit under our Constitution cannot and will not be made party to lawless invasions of the constitutional rights of citizens by permitting unhindered governmental use of the fruits of such invasions. Thus in our system evidentiary rulings provide the context in which the judicial process of inclusion and exclusion approves some conduct as comporting with constitutional guarantees and disapproves other actions by state agents. A ruling admitting evidence in a criminal trial, we recognize, has the necessary effect of legitimizing the conduct which produced the evidence, while an application of the exclusionary rule withholds the constitutional imprimatur.

The exclusionary rule has its limitations, however, as a tool of judicial control. It cannot properly be invoked to exclude the products of legitimate police investigative techniques on the ground that much conduct which is closely similar involves unwarranted intrusions upon constitutional protections. Moreover, in some contexts the rule is ineffective as a deterrent. Street encounters between citizens and police officers are incredibly rich in diversity. They range from wholly friendly exchanges of pleasantries or mutually useful information to hostile confrontations of armed men involving arrests, or injuries, or loss of life. Moreover, hostile confrontations are not all of a piece. Some of them begin in a friendly enough manner, only to take a different turn upon the injection of some unexpected element into the conversation. Encounters are initiated by the police for a wide variety of purposes, some of which are wholly unrelated to a desire to prosecute for crime.9 Doubtless some *14police “field interrogation” conduct violates the Fourth Amendment. But a stern refusal by this Court to condone such activity does not necessarily render it responsive to the exclusionary rule. Regardless of how effective the rule may be where obtaining convictions is an important objective of the police,10 it is powerless to deter invasions of constitutionally guaranteed rights where the police either have no interest in prosecuting or are willing to forgo successful prosecution in the interest of serving some other goal.

Proper adjudication of cases in which the exclusionary rule is invoked demands a constant awareness of these limitations. The wholesale harassment by certain elements of the police community, of which minority groups, particularly Negroes, frequently complain,11 will not be *15stopped by the exclusion of any evidence from any criminal trial. Yet a rigid and unthinking application of the exclusionary rule, in futile protest against practices which it can never be used effectively to control, may exact a high toll in human injury and frustration of efforts to prevent crime. No judicial opinion can comprehend the protean variety of the street encounter, and we can only judge the facts of the case before us. Nothing we say today is to be taken as indicating approval of police conduct outside the legitimate investigative sphere. Under our decision, courts still retain their traditional responsibility to guard against police conduct which is overbearing or harassing, or which trenches upon personal security without the objective evidentiary justification which the Constitution requires. When such conduct is identified, it must be condemned by the judiciary and its fruits must be excluded from evidence in criminal trials. And, of course, our approval of legitimate and restrained investigative conduct undertaken on the basis of ample factual justification should in no way discourage the employment of other remedies than the exclusionary rule to curtail abuses for which that sanction may prove inappropriate.

Having thus roughly sketched the perimeters of the constitutional debate over the limits on police investigative conduct in general and the background against which this case presents itself, we turn our attention to the quite narrow question posed by the facts before us: whether it is always unreasonable for a policeman to seize a person and subject him to a limited search for weapons unless there is probable cause for an arrest. *16Given the narrowness of this question, we have no occasion to canvass in detail the constitutional limitations upon the scope of a policeman’s power when he confronts a citizen without probable cause to arrest him.

II.

Our first task is to establish at what point in this encounter the Fourth Amendment becomes relevant. That is, we must decide whether and when Officer McFadden “seized” Terry and whether and when he conducted a “search.” There is some suggestion in the use of such terms as “stop” and “frisk” that such police conduct is outside the purview of the Fourth Amendment because neither action rises to the level of a “search” or “seizure” within the meaning of the Constitution.12 We emphatically reject this notion. It is quite plain that the Fourth Amendment governs “seizures” of the person which do not eventuate in a trip to the station house and prosecution for crime — “arrests” in traditional terminology. It must be recognized that whenever a police officer accosts an individual and restrains his freedom to walk away, he has “seized” that person. And it is nothing less than sheer torture of the English language to suggest that a careful exploration of the outer surfaces of a person’s clothing all over his or her body in an attempt to find weapons is not a “search.” Moreover, it is simply fantastic to urge that such a procedure *17performed in public by a policeman while the citizen stands helpless, perhaps facing a wall with his hands raised, is a “petty indignity.” 13 It is a serious intrusion upon the sanctity of the person, which may inflict great indignity and arouse strong resentment, and it is not to be undertaken lightly.14

The danger in the logic which proceeds upon distinctions between a “stop” and an “arrest,” or “seizure” of the person, and between a “frisk” and a “search” is twofold. It seeks to isolate from constitutional scrutiny the initial stages of the contact beween the policeman and the citizen. And by suggesting a rigid all-or-nothing model of justification and regulation under the Amendment, it obscures the utility of limitations upon the scope, as well as the initiation, of police action as a means of constitutional regulation.15 This Court has held in *18the past that a search which is reasonable at its inception may violate the Fourth Amendment by virtue of its intolerable intensity and scope. Kremen v. United States, 353 U. S. 346 (1957); Go-Bart Importing Co. v. *19United States, 282 U. S. 344, 356-358 (1931); see United States v. Di Re, 332 U. S. 581, 586-587 (1948). The scope of the search must be “strictly tied to and justified by” the circumstances which rendered its initiation permissible. Warden v. Hayden, 387 U. S. 294, 310 (1967) (Mr. Justice Fortas, concurring); see, e. g., Preston v. United States, 376 U. S. 364, 367-368 (1964); Agnello v. United States, 269 U. S. 20, 30-31 (1925).

The distinctions of classical “stop-and-frisk” theory thus serve to divert attention from the central inquiry under the Fourth Amendment — the reasonableness in all the circumstances of the particular governmental invasion of a citizen’s personal security. “Search” and “seizure” are not talismans. We therefore reject the notions that the Fourth Amendment does not come into play at all as a limitation upon police conduct if the officers stop short of something called a “technical arrest” or a “full-blown search.”

In this case there can be no question, then, that Officer McFadden “seized” petitioner and subjected him to a “search” when he took hold of him and patted down the outer surfaces of his clothing. We must decide whether at that point it was reasonable for Officer McFadden to have interfered with petitioner’s personal security as he did.16 And in determining whether the seizure and search were “unreasonable” our inquiry *20is a dual one — whether the officer's action was justified at its inception, and whether it was reasonably related in scope to the circumstances which justified the interference in the first place.

III.

If this case involved police conduct subject to the Warrant Clause of the Fourth Amendment, we would have to ascertain whether “probable cause” existed to justify the search and seizure which took place. However, that is not the case. We do not retreat from our holdings that the police must, whenever practicable, obtain advance judicial approval of searches and seizures through the warrant procedure, see, e. g., Katz v. United States, 389 U. S. 347 (1967); Beck v. Ohio, 379 U. S. 89, 96 (1964); Chapman v. United States, 365 U. S. 610 (1961), or that in most instances failure to comply with the warrant requirement can only be excused by exigent circumstances, see, e. g., Warden v. Hayden, 387 U. S. 294 (1967) (hot pursuit); cf. Preston v. United States, 376 U. S. 364, 367-368 (1964). But we deal here with an entire rubric of police conduct — necessarily swift action predicated upon the on-the-spot observations of the officer on the beat — which historically has not been, and as a practical matter could not be, subjected to the warrant procedure. Instead, the conduct involved in this case must be tested by the Fourth Amendment's general proscription against unreasonable searches and seizures.17

Nonetheless, the notions which underlie both the warrant procedure and the requirement of probable cause remain fully relevant in this context. In order to assess the reasonableness of Officer McFadden’s conduct as a general proposition, it is necessary “first to focus upon *21the governmental interest which allegedly justifies official intrusion upon the constitutionally protected interests of the private citizen,” for there is “no ready test for determining reasonableness other than by balancing the need to search [or seize] against the invasion which the search [or seizure] entails.” Camara v. Municipal Court, 387 U. S. 523, 534-535, 536-537 (1967). And in justifying the particular intrusion the police officer must be able to point to specific and articulable facts which, taken together with rational inferences from those facts, reasonably warrant that intrusion.18 The scheme of the Fourth Amendment becomes meaningful only when it is assured that at some point the conduct of those charged with enforcing the laws can be subjected to the more detached, neutral scrutiny of a judge who must evaluate the reasonableness of a particular search or seizure in light of the particular circumstances.19 And in making that assessment it is imperative that the facts be judged against an objective standard: would the facts *22available to the officer at the moment of the seizure or the search “warrant a man of reasonable caution in the belief” that the action taken was appropriate? Cf. Carroll v. United States, 267 U. S. 132 (1925); Beck v. Ohio, 379 U. S. 89, 96-97 (1964).20 Anything less would invite intrusions upon constitutionally guaranteed rights based on nothing more substantia] than inarticulate hunches, a result this Court has. consistently refused to sanction. See, e. g., Beck v. Ohio, supra; Rios v. United States, 364 U. S. 253 (1960); Henry v. United States, 361 U. S. 98 (1959). And simple “'good faith on the part of the arresting officer is not enough.’ ... If subjective good faith alone were the test, the protections of the Fourth Amendment would evaporate, and the people would be 'secure in their persons, houses, papers, and effects,’ only in the discretion of the police.” Beck v. Ohio, supra, at 97.

Applying these principles to this case, we consider first the nature and extent of the governmental interests involved. One general interest is of course that of effective crime prevention and detection; it is this interest which underlies the recognition that a police officer may in appropriate circumstances and in an appropriate manner approach a person for purposes of investigating possibly criminal behavior even though there is no probable cause to make an arrest. It was this legitimate investigative function Officer McFadden was discharging when he decided to approach petitioner and his companions. He had observed Terry, Chilton, and Katz go through a series of acts, each of them perhaps innocent in itself, but which taken together warranted further investigation. There is nothing unusual in two men standing together on a street corner, perhaps waiting for someone. Nor is there anything suspicious about people *23in such circumstances strolling up and down the street, singly or in pairs. Store windows, moreover, are made to be looked in. But the story is quite different where, as here, two men hover about a street corner for an extended period of time, at the end of which it becomes apparent that they are not waiting for anyone or anything ; where these men pace alternately along an identical route, pausing to stare in the same store window roughly 24 times; where each completion of this route is followed immediately by a conference between the two men on the corner; where they are joined in one of these conferences by a third man who leaves swiftly; and where the two men finally follow the third and rejoin him a couple of blocks away. It would have been poor police work indeed for an officer of 30 years’ experience in the detection of thievery from stores in this same neighborhood to have failed to investigate this behavior further.

The crux of this case, however, is not the propriety of Officer McFadden’s taking steps to investigate petitioner’s suspicious behavior, but rather, whether there was justification for McFadden’s invasion of Terry’s personal security by searching him for weapons in the course of that investigation. We are now concerned with more than the governmental interest in investigating crime; in addition, there is the more immediate interest of the police officer in taking steps to assure himself that the person with whom he is dealing is not armed with a weapon that could unexpectedly and fatally be used against him. Certainly it would be unreasonable to require that police officers take unnecessary risks in the performance of their duties. American criminals have a long tradition of armed violence, and every year in this country many law enforcement officers are killed in the line of duty, and thousands more are wounded. *24Virtually all of these deaths and a substantial portion of the injuries are inflicted with guns and knives.21

In view of these facts, we cannot blind ourselves to the need for law enforcement officers to protect themselves and other prospective victims of violence in situations where they may lack probable cause for an arrest. When an officer is justified in believing that the individual whose suspicious behavior he is investigating at close range is armed and presently dangerous to the officer or to others, it would appear to be clearly unreasonable to deny the officer the power to take necessary measures to determine whether the person is in fact carrying a weapon and to neutralize the threat of physical harm.

We must still consider, however, the nature and quality of the intrusion on individual rights which must be accepted if police officers are to be conceded the right to search for weapons in situations where probable cause to arrest for crime is lacking. Even a limited search of the outer clothing for weapons constitutes a severe, *25though brief, intrusion upon cherished personal security, and it must surely be an annoying, frightening, and perhaps humiliating experience. Petitioner contends that such an intrusion is permissible only incident to a lawful arrest, either for a crime involving the possession of weapons or for a crime the commission of which led the officer to investigate in the first place. However, this argument must be closely examined.

Petitioner does not argue that a police officer should refrain from making any investigation of suspicious circumstances until such time as he has probable cause to make an arrest; nor does he deny that police officers in properly discharging their investigative function may find themselves confronting persons who might well be armed and dangerous. Moreover, he does not say that an officer is always unjustified in searching a suspect to discover weapons. Rather, he says it is unreasonable for the policeman to take that step until such time as the situation evolves to a point where there is probable cause to make an arrest. When that point has been reached, petitioner would concede the officer’s right to conduct a search of the suspect for weapons, fruits or instrumentalities of the crime, or “mere” evidence, incident to the arrest.

There are two weaknesses in this line of reasoning, however. First, it fails to take account of traditional limitations upon the scope of searches, and thus recognizes no distinction in purpose, character, and extent between a search incident to an arrest and a limited search for weapons. The former, although justified in part by the acknowledged necessity to protect the arresting officer from assault with a concealed weapon, Preston v. United States, 376 U. S. 364, 367 (1964), is also justified on other grounds, ibid., and can therefore involve a relatively extensive exploration of the person. A search for weapons in the absence of probable cause to *26arrest, however, must, like any other search, be strictly circumscribed by the exigencies which justify its initiation. Warden v. Hayden, 387 U. S. 294, 310 (1967) (Mr. Justice Fortas, concurring). Thus it must be limited to that which is necessary for the discovery of weapons which might be used to harm the officer or others nearby, and may realistically be characterized as something less than a “full” search, even though it remains a serious intrusion.

A second, and related, objection to petitioner’s argument is that it assumes that the law of arrest has already worked out the balance between the particular interests involved here — the neutralization of danger to the policeman in the investigative circumstance and the sanctity of the individual. But this is not so. An arrest is a wholly different kind of intrusion upon individual freedom from a limited search for weapons, and the interests each is designed to serve are likewise quite different. An arrest is the initial stage of a criminal prosecution. It is intended to vindicate society’s interest in having its laws obeyed, and it is inevitably accompanied by future interference with the individual’s freedom of movement, whether or not trial or conviction ultimately follows.22 The protective search for weapons, on the other hand, constitutes a brief, though far from inconsiderable, intrusion upon the sanctity of the person. It does not follow that because an officer may lawfully arrest a person only when he is apprised of facts sufficient to warrant a belief that the person has committed or is committing a crime, the officer is equally unjustified, absent that kind of evidence, in making any intrusions short of an arrest. Moreover, a perfectly reasonable apprehension of danger may arise long before the officer is possessed of adequate information to justify taking a person into custody for *27the purpose of prosecuting him for a crime. Petitioner’s reliance on cases which have worked out standards of reasonableness with regard to “seizures” constituting arrests and searches incident thereto is thus misplaced. It assumes that the interests sought to be vindicated and the invasions of personal security may be equated in the two cases, and thereby ignores a vital aspect of the analysis of the reasonableness of particular types of conduct under the Fourth Amendment. See Camara v. Municipal Court, supra.

Our evaluation of the proper balance that has to be struck in this type of case leads us to conclude that there must be a narrowly drawn authority to permit a reasonable search for weapons for the protection of the police officer, where he has reason to believe that he is dealing with an armed and dangerous individual, regardless of whether he has probable cause to arrest the individual for a crime. The officer need not be absolutely certain that the individual is armed; the issue is whether a reasonably prudent man in the circumstances would be warranted in the belief that his safety or that of others was in danger. Cf. Beck v. Ohio, 379 U. S. 89, 91 (1964); Brinegar v. United States, 338 U. S. 160, 174-176 (1949); Stacey v. Emery, 97 U. S. 642, 645 (1878).23 And in determining whether the officer acted reasonably in such circumstances, due weight must be given, not to his inchoate and unparticularized suspicion or “hunch,” but to the specific reasonable inferences which he is entitled to draw from the facts in light of his experience. Cf. Brinegar v. United States supra.

IY.

We must now examine the conduct of Officer McFadden in this case to determine whether his search and seizure of petitioner were reasonable, both at their in*28ception and as conducted. He had observed Terry, together with Chilton and another man, acting in a manner he took to be preface to a “stick-up.” We think on the facts and circumstances Officer McFadden detailed before the trial judge a reasonably prudent man would have been warranted in believing petitioner was armed and thus presented a threat to the officer’s safety while he was investigating his suspicious behavior. The actions of Terry and Chilton were consistent with McFadden’s hypothesis that these men were contemplating a daylight robbery — which, it is reasonable to assume, would be likely to involve the use of weapons — and nothing in their conduct from the time he first noticed them until the time he confronted them and identified himself as a police officer gave him sufficient reason to negate that hypothesis. Although the trio had departed the original scene, there was nothing to indicate abandonment of an intent to commit a robbery at some point. Thus, when Officer McFadden approached the three men gathered before the display window at Zucker’s store he had observed enough to make it quite reasonable to fear that they were armed; and nothing in their response to his hailing them, identifying himself as a police officer, and asking their names served to dispel that reasonable belief. We cannot say his decision at that point to seize Terry and pat his clothing for weapons was the product of a volatile or inventive imagination, or was undertaken simply as an act of harassment; the record evidences the tempered act of a policeman who in the course of an investigation had to make a quick decision as to how to protect himself and others from possible danger, and took limited steps to do so.

The manner in which the seizure and search were conducted is, of course, as vital a part of the inquiry as whether they were warranted at all. The Fourth Amendment proceeds as much by limitations upon the *29scope of governmental action as by imposing preconditions upon its initiation. Compare Katz v. United States, 389 U. S. 347, 354-356 (1967). The entire deterrent purpose of the rule excluding evidence seized in violation of the Fourth Amendment rests on the assumption that “limitations upon the fruit to be gathered tend to limit the quest itself.” United States v. Poller, 43 F. 2d 911, 914 (C. A. 2d Cir. 1930); see, e. g., Linkletter v. Walker, 381 U. S. 618, 629-635 (1965); Mapp v. Ohio, 367 U. S. 643 (1961); Elkins v. United States, 364 U. S. 206, 216-221 (1960). Thus, evidence may not be introduced if it was discovered by means of a seizure and search which were not reasonably related in scope to the justification for their initiation. Warden v. Hayden, 387 U. S. 294, 310 (1967) (Mr. Justice Fortas, concurring).

We need not develop at length in this case, however, the limitations which the Fourth Amendment places upon a protective seizure and search for weapons. These limitations will have to be developed in the concrete factual circumstances of individual cases. See Sibron v. New York, post, p. 40, decided today. Suffice it to note that such a search, unlike a search without a warrant incident to a lawful arrest, is not justified by any need to prevent the disappearance or destruction of evidence of crime. See Preston v. United States, 376 U. S. 364, 367 (1964). The sole justification of the search in the present situation is the protection of the police officer and others nearby, and it must therefore be confined in scope to an intrusion reasonably designed to discover guns, knives, clubs, or other hidden instruments for the assault of the police officer.

The scope of the search in this case presents no serious problem in light of these standards. Officer McFadden patted down the outer clothing of petitioner and his two companions. He did not place his hands in their pockets or under the outer surface of their garments until he had *30felt weapons, and then he merely reached for and removed the guns. He never did invade Katz’ person beyond the outer surfaces of his clothes, since he discovered nothing in his pat-down which might have been a weapon. Officer McFadden confined his search strictly to what was minimally necessary to learn whether the men were armed and to disarm them once he discovered the weapons. He did not conduct a general exploratory search for whatever evidence of criminal activity he might find.

V.

We conclude that the revolver seized from Terry was properly admitted in evidence against him. At the time he seized petitioner and searched him for weapons, Officer McFadden had reasonable grounds to believe that petitioner was armed and dangerous, and it was necessary for the protection of himself and others to take swift measures to discover the true facts and neutralize the threat of harm if it materialized. The policeman carefully restricted his search to what was appropriate to the discovery of the particular items which he sought. Each case of this sort will, of course, have to be decided on its own facts. We merely hold today that where a police officer observes unusual conduct which leads him reasonably to conclude in light of his experience that criminal activity may be afoot and that the persons with whom he is dealing may be armed and presently dangerous, where in the course of investigating this behavior he identifies himself as a policeman and makes reasonable inquiries, and where nothing in the initial stages of the encounter serves to dispel his reasonable fear for his own or others’ safety, he is entitled for the protection of himself and others in the area to conduct a carefully limited search of the outer clothing of such persons in an attempt to discover weapons which might be used to assault him. *31Such a search is a reasonable search under the Fourth Amendment, and any weapons seized may properly be introduced in evidence against the person from whom they were taken. Affirmed.

Mr. Justice Black concurs in the judgment and the opinion except where the opinion quotes from and relies upon this Court’s opinion in Katz v. United States and the concurring opinion in Warden v. Hayden.

Mr. Justice Harlan,

concurring.

While I unreservedly agree with the Court’s ultimate holding in this case, I am constrained to fill in a few gaps, as I see them, in its opinion. I do this because what is said by this Court today will serve as initial guidelines for law enforcement authorities and courts throughout the land as this important new field of law develops.

A police officer’s right to make an on-the-street “stop” and an accompanying “frisk” for weapons is of course bounded by the protections afforded by the Fourth and Fourteenth Amendments. The Court holds, and I agree, that while the right does not depend upon possession by the officer of a valid warrant, nor upon the existence of probable cause, such activities must be reasonable under the circumstances as the officer credibly relates them in court. Since the question in this and most cases is whether evidence produced by a frisk is admissible, the problem is to determine what makes a frisk reasonable.

If the State of Ohio were to provide that police officers could, on articulable suspicion less than probable cause, forcibly frisk and disarm persons thought to be carrying concealed weapons, I would have little doubt that action taken pursuant to such authority could be constitutionally reasonable. Concealed weapons create an im*32mediate and severe danger to the public, and though that danger might not warrant routine general weapons checks, it could well warrant action on less than a “probability.” I mention this line of analysis because I think it vital to point out that it cannot be applied in this case. On the record before us Ohio has not clothed its policemen with routine authority to frisk and disarm on suspicion; in the absence of state authority, policemen have no more right to “pat down” the outer clothing of passers-by, or of persons to whom they address casual questions, than does any other citizen. Consequently, the Ohio courts did not rest the constitutionality of this frisk upon any general authority in Officer McFadden to take reasonable steps to protect the citizenry, including himself, from dangerous weapons.

The state courts held, instead, that when an officer is lawfully confronting a possibly hostile person in the line of duty he has a right, springing only from the necessity of the situation and not from any broader right to disarm, to frisk for his own protection. This holding, with which I agree and with which I think the Court agrees, offers the only satisfactory basis I can think of for affirming this conviction. The holding has, however, two logical corollaries that I do not think the Court has fully expressed.

In the first place, if the frisk is justified in order to protect the officer during an encounter with a citizen, the officer must first have constitutional grounds to insist on an encounter, to make a forcible stop. Any person, including a policeman, is at liberty to avoid a person he considers dangerous. If and when a policeman has a right instead to disarm such a person for his own protection, he must first have a right not to avoid him but to be in his presence. That right must be more than the liberty (again, possessed by every citizen) to address questions to other persons, for ordinarily the person *33addressed has an equal right to ignore his interrogator and walk away; he certainly need not submit to a frisk for the questioner’s protection. I would make it perfectly clear that the right to frisk in this case depends upon the reasonableness of a forcible stop to investigate a suspected crime.

Where such a stop is reasonable, however, the right to frisk must be immediate and automatic if the reason for the stop is, as here, an articulable suspicion of a crime of violence. Just as a full search incident to a lawful arrest requires no additional justification, a limited frisk incident to a lawful stop must often be rapid and routine. There is no reason why an officer, rightfully but forcibly confronting a person suspected of a serious crime, should have to ask one question and take the risk that the answer might be a bullet.

The facts of this case are illustrative of a proper stop and an incident frisk. Officer McFadden had no probable cause to arrest Terry for anything, but he had observed circumstances that would reasonably lead an experienced, prudent policeman to suspect that Terry was about to engage in burglary or robbery. His justifiable suspicion afforded a proper constitutional basis for accosting Terry, restraining his liberty of movement briefly, and addressing questions to him, and Officer McFadden did so. When he did, he had no reason whatever to suppose that Terry might be armed, apart from the fact that he suspected him of planning a violent crime. McFadden asked Terry his name, to which Terry “mumbled something.” Whereupon McFadden, without asking Terry to speak louder and without giving him any chance to explain his presence or his actions, forcibly frisked him.

I would affirm this conviction for what I believe to be the same reasons the Court relies on. I would, however, make explicit what I think is implicit in affirmance on *34the present facts. Officer McFadden’s right to interrupt Terry’s freedom of movement and invade his privacy arose only because circumstances warranted forcing an encounter with Terry in an effort to prevent or investigate a crime. Once that forced encounter was justified, however, the officer's right to take suitable measures for his own safety followed automatically.

Upon the foregoing premises, I join the opinion of the Court.

Mr. Justice White,

concurring.

I join the opinion of the Court, reserving judgment, however, on some of the Court’s general remarks about the scope and purpose of the exclusionary rule which the Court has fashioned in the process of enforcing the Fourth Amendment.

Also, although the Court puts the matter aside in the context of this case, I think an additional word is in order concerning the matter of interrogation during an investigative stop. There is nothing in the Constitution which prevents a policeman from addressing questions to anyone on the streets. Absent special circumstances, the person approached may not be detained or frisked but may refuse to cooperate and go on his way. However, given the proper circumstances, such as those in this case, it seems to me the person may be briefly detained against his will while pertinent questions are directed to him. Of course, the person stopped is not obliged to answer, answers may not be compelled, and refusal to answer furnishes no basis for an arrest, although it may alert the officer to the need for continued observation. In my view, it is temporary detention, warranted by the circumstances, which chiefly justifies the protective frisk for weapons. Perhaps the frisk itself, where proper, will have beneficial results whether questions are asked or not. If weapons are found, an arrest will fol*35low. If none are found, the frisk may nevertheless serve preventive ends because of its unmistakable message that suspicion has been aroused. But if the investigative stop is sustainable at all, constitutional rights are not necessarily violated if pertinent questions are asked and the person is restrained briefly in the process.

Mr. Justice Douglas-,

dissenting.

I agree that petitioner was “seized” within the meaning of the Fourth Amendment. I also agree that frisking petitioner and his companions for guns was a “search.” But it is a mystery how that “search” and that “seizure” can be constitutional by Fourth Amendment standards, unless there was “probable cause” 1 to believe that (1) a crime had been committed or (2) a crime was in the process of being committed or (3) a crime was about to be committed.

The opinion of the Court disclaims the existence of “probable cause.” If loitering were in issue and that *36was the offense charged, there would be “probable cause” shown. But the crime here is carrying concealed weapons; 2 and there is no basis for concluding that the officer had “probable cause” for believing that that crime was being committed. Had a warrant been sought, a magistrate would, therefore, have been unauthorized to issue one, for he can act only if there is a showing of “probable cause.” We hold today that the police have greater authority to make a “seizure” and conduct a “search” than a judge has to authorize such action. We have said precisely the opposite over and over again.3

*37In other words, police officers up to today have been permitted to effect arrests or searches without warrants only when the facts within their personal knowledge would satisfy the constitutional standard of probable cause. At the time of their “seizure” without a warrant they must possess facts concerning the person arrested that would have satisfied a magistrate that “probable cause” was indeed present. The term “probable cause” rings a bell of certainty that is not sounded by phrases such as “reasonable suspicion.” Moreover, the meaning of “probable cause” is deeply imbedded in our constitutional history. As we stated in Henry v. United States, 361 U. S. 98, 100-102:

“The requirement of probable cause has roots that are deep in our history. The general warrant, in which the name of the person to be arrested was left blank, and the writs of assistance, against which James Otis inveighed, both perpetuated the oppressive practice of allowing the police to arrest and search on suspicion. Police control took the place of judicial control, since no showing of 'probable cause’ before a magistrate was required.

“That philosophy [rebelling against these practices] later was reflected in the Fourth Amendment. And as the early American decisions both before and immediately after its adoption show, common rumor or report, suspicion, or even ‘strong reason to suspect’ was not adequate to support a warrant *38for arrest. And that principle has survived to this day. . . .

“. . . It is important, we think, that this requirement [of probable cause] be strictly enforced, for the standard set by the Constitution protects both the officer and the citizen. If the officer acts with probable cause, he is protected even though it turns out that the citizen is innocent. . . . And while a search without a warrant is, within limits, permissible if incident to a lawful arrest, if an arrest without a warrant is to support an incidental search, it must be made with probable cause. . . . This immunity of officers cannot fairly be enlarged without jeopardizing the privacy or security of the citizen.”

The infringement on personal liberty of any “seizure” of a person can only be “reasonable” under the Fourth Amendment if we require the police to possess “probable cause” before they seize him. Only that line draws a meaningful distinction between an officer’s mere inkling and the presence of facts within the officer’s personal knowledge which would convince a reasonable man that the person seized has committed, is committing, or is about to commit a particular crime. “In dealing with probable cause, ... as the very name implies, we deal with probabilities. These are not technical; they are the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.” Brinegar v. United States, 338 U. S. 160, 175.

To give the police greater power than a magistrate is to take a long step down the totalitarian path. Perhaps such a step is desirable to cope with modern forms of lawlessness. But if it is taken, it should be the deliberate choice of the people through a constitutional amendment. *39Until the Fourth Amendment, which is closely allied with the Fifth,4 is rewritten, the person and the effects of the individual are beyond the reach of all government agencies until there are reasonable grounds to believe (probable cause) that a criminal venture has been launched or is about to be launched.

There have been powerful hydraulic pressures throughout our history that bear heavily on the Court to water down constitutional guarantees and give the police the upper hand. That hydraulic pressure has probably never been greater than it is today.

Yet if the individual is no longer to be sovereign, if the police can pick him up whenever they do not like the cut of his jib, if they can “seize” and “search” him in their discretion, we enter a new regime. The decision to enter it should be made only after a full debate by the people of this country.

Mr. Justice Powell

delivered the opinion of the Court.

The issue before us is ah important one for the people of our country and their Government. It involves the delicate question of the President’s power, acting through the Attorney General, to authorize electronic surveillance in internal security matters without prior judicial approval. Successive.Presidents for more, than one-quarter of a century have authorized such surveillance in varying degrees,1 without guidance from the Congress or a definitive decision of this Court.. This case brings the issue here for the first time. Its resolution is a matter of national concern, requiring sensitivity both to the Government’s right to protect itself from unlawful subversion and attack and to the citizen’s right to be secure in his privacy against unreasonable Government intrusion.

This case arises from a criminal proceeding in the United States District Court for the Eastern District of Michigan, in which the United States charged three defendants with conspiracy to destroy Government property in violation of 18 U. S. C. § 371. One of the defendants, Plamondon, was charged with the dynamite bombing of an office of the Central Intelligence Agency in Ann Arbor, Michigan.

During pretrial proceedings, the defendants moved to compel the United States to disclose certain electronic *300surveillance information and to conduct a hearing to determine whether this information “tainted” the evidence on which the indictment was based or which theGovernment intended to offer at trial. In response, the- Government filed an affidavit of the Attorney General, acknowledging that its agents had overheard conversations in which Plamondon had participated. The affidavit also stated that the Attorney General approved the wiretaps “to gather intelligence information deemed necessary to protect the nation from attempts of domestic organizations to attack and subvert the existing structure of the Government.” 2 The logs of the surveillance *301were filed in a sealed exhibit for in camera, inspection by the District Court. •

On the basis of the Attorney General’s affidavit and the sealed exhibit, the' Government' asserted that the surveillance was lawful, though conducted without prior judicial approval, as a reasonable exercise of- the President’s power (exercised through the Attorney General) to protect the national security. The District Court held that the surveillance violated the Fourth . Amendment, and ordered the Government to 'make full, disclosure to Plamondon of his overheard conversations. 321 F. Supp. 1074 (ED Mich. 1971).

The Government then filed in the Court of Appeals for the Sixth Circuit a petition for-a writ of mandamus to set aside the District Court order, which was stayed pending final disposition of the case. ..After- concluding that it had jurisdiction,3 that ‘court held that the surveillance was unlawful and that the District Court had properly .required disclosure of the overheard conversations, 444 F. 2d 651 (1971). We granted certiorari, 403 U. S. 930.

I

Title III of the Omnibus Crime Control and Safe Streets Act, 18 U. S. C. §§ 2510-2520, authorizes the use of electronic surveillance for classes of crimes care*302fully specified in 18 U. S. C. § 2516. Such surveillance is subject to prior court order. Section 2518 sets forth the detailed and particularized application necessary to obtain such an order as well as carefully circumscribed conditions for its use. The Act represents a comprehensive attempt by Congress to promote more effective control of crime while protecting the privacy of individual thought and expression. Much of Title III was drawn to meet the constitutional requirements for electronic surveillance enunciated by this Court in Berger v. New York, 388 U. S. 41 (1967), and Katz v. United States, 389 U. S. 347 (1967).

Together with the elaborate surveillance requirements in Title III, there is the following proviso; 18 U. S. C. §2511(3):

“Nothing contained in this chapter or in section 605 of the Communications Act of 1934 (48 Stat. 1143; 47 U. S. C. 605) shall limit the constitutional power of the President to take such measures as he deems necessary to protect the Nation against actual or potential attack or other hostile acts of a foreign power, to obtain foreign' intelligence information deemed essential to the security of the United States, or to protect national security information against foreign intelligence activities. Nor shall anything contained in this chapter he deemed to limit the constitutional power, of the President to take such measures as he deems necessary to protect the United States against the overthrow of the Government by force or other unlawful means, or against any other clear and present danger to the structure or existence of the Government. The contents of any wire or oral communication intercepted by authority of the President in the exercise of the foregoing powers may be received in evidence in any trial hearing, *303or other proceeding only where such interception was reasonable, and shall not be otherwise used or disclosed except as is necessary to implement that power.” (Emphasis supplied.)

The Government relies on § 2511 (3). It argues that “in excepting national security surveillances from the Act’s warrant requirement. Congress recognized the President’s authority to conduct such, surveillances without prior, judicial approval.” Brief for United States 7, 28. The section thus is viewed as a recognition or affirmance of a constitutional authority in the President to conduct warrantless domestic security surveillance such as that involved in this case.

We think the language of § 2511 (3), as well as the legislative history of the statute, refutes this-interpretation. . The relevant language is that:

“Nothing contained in this chapter . . . shall limit the constitutional power of the President to take such measures ás he deems necessary to protect.. .”

against the dangers specified. At most, this is an implicit recognition that the President does have certain powers in the specified areas. Few would doubt this, as the section refers — among other things — to protection “against actual or potential attack or other hostile acts of a foreign power.” But so far as the use of the President’s electronic surveillance power is concerned, the language is essentially neutral.

Section 2511 (3) certainly confers no power, as the language is wholly inappropriate for such a purpose. It merely provides that the Act shall not be interpreted to limit or disturb such power as the President may have under the Constitution. In short, Congress simply left presidential powers where it found thém. This view is reinforced by the general context of Title III. Section 2511 (1) broadly prohibits the use of electronic *304surveillance “{ejxcept as otherwise specifically provided in this chapter.” Subsection (2) thereof contains four specific exceptions. In each of the specified exceptions, the statutory language is as follows:

“It shall not be unlawful ... to intercept” the particular type of communication described.4

The language of subsection (3), here involved, is to be contrasted with the language of the exceptions set forth in the preceding subsection. Rather than stating that warrantless presidential uses of electronic surveillance “shall not be unlawful” and thus employing the standard language of exception, subsection (3) merely disclaims any intention to “limit the constitutional power of the President.”

The express grant of authority to conduct surveil-lances is found in § 2516, which authorizes the Attorney General to make application to a federal judge when surveillance may provide evidence of certain offenses. These offenses are described with meticulous care and specificity.

Where the Act authorizes surveillance, the procedure to be followed is specified in §2518. Subsection (1) thereof requires application to a judge of competent jurisdiction for a prior order of approval, and states in detail the information réquired in such application.5 *305Subsection (3) prescribes the necessary eleménts of probable cause which the .judge must find before issuing an order authorizing an interception. Subsection (4) sets forth the required contents of such an order.. *306Subsection (5) sets strict time limits on an order. Provision is made in subsection (7) for “an emergency-situation” found to exist by the Attorney General (or by the principal prosecuting attorney of a State) “with respect to conspiratorial activities threatening the national security interest.” In such a situation, emergency surveillance may be conducted “if an application for an order approving the interception is made . . . within forty-eight hours.” If such an order is not obtained, or the application therefor is denied, the interception is deemed to be a violation of the Act.

In view of these and other interrelated provisions delineating permissible interceptions of particular criminal activity upon carefully specified conditions, it would have been incongruous for Congress to have legislated with respect to the important and complex area of national security in a single brief and nebulous paragraph. This would not comport with the sensitivity of the problem involved or with the extraordinary care Congress exercised in drafting other sections of the Act. We therefore think the conclusion inescapable that Congress only intended to make clear that the Act simply did not legislate with respect to national security surveillances.6

The legislative history of §2511(3) supports this interpretation. Most relevant is the colloquy between Senators Hart, Holland, and McClellan on the Senate floor:

“Mr.'HOLLAND. . .. The section [2511(3)] from which the Senator [Hart] has read does not affirma*307tively give any power. ... We are not affirmatively conferring any power upon the President. We are simply saying that nothing herein shall limit such power as the President has under the Constitution. . . . We certainly do not grant him a thing.

“There is nothing affirmative in this statement.

“Mr. McCLELLAN. Mr. President, we make it understood that we are not trying to take anything away from-him.

“Mr. HOLLAND. The Senator is correct.

“Mr. HART. Mr. President, there is no intention • here to expand by this language a constitutional power. Clearly we could not do so.

“Mr. McCLELLAN. Even though intended, we could not do so.

“Mr. HART. . . . However, we are agreed that this language should not be regarded as intending to grant any authority, including authority to put a bug on, that the President does not have now.

“In addition, Mr. President, as I think our exchange makes clear, nothing in section 2511 (3) even attempts to define the limits of the. President’s national security power under present law, which I have always found extremely vague .... .Section 2511(8) 'merely says that if the President has such a power, then its exercise is in no way affected by title III.” 7 (Emphasis supplied.)

*308One could hardly expect a clearer expression of congressional neutrality. The debate above explicitly indicates that nothing in § 2511 (3) was intended to expand or to contract or to define whatever presidential surveillance powers existed in matters affecting the national security. If we could accept the Government's characterization of § 2511 (3) as a congressionally prescribed exception to the general requirement of a warrant, it would be necessary to consider the question of whether the surveillance in this casé came within the exception and, if so, whether the statutory exception was itself constitutionally valid. But viewing § 2511 (3) as a congressional' disclaimer and expression of neutrality, we hold that the statute is not the measure of the executive authority asserted in this case. Rather, we must look to the constitutional powers of the President.

II

It is important at the outset to emphasize the limited nature of the question before the Court. This case raises- no constitutional challenge to electronic surveillance as specifically authorized by Title III of the Omnibus Crime Control and Safe Streets Act of 1968. Nor. is there any question or doubt as to the necessity of obtaining a warrant in the surveillance of crimes unrelated to the national security interest. Katz v. United States, 389 U. S. 347 (1967); Berger v. New York, 388 U. S. 41 (1967). Further, the instant case requires no judgment on the scope of the President's surveillance power with respect to the activities of foreign powers, within or without this country. The Attorney General’s affidavit in this case states that, the surveillances were *309“deemed, necessary to protect the nation from attempts of domestic organizations to attack and subvert the existing structure of Government” (emphasis supplied). There -is no evidence of any involvement, directly or indirectly, of a foreign power.8

Our present inquiry, though important, is therefore a narrow one. It addresses a question left open by. Katz, supra, at 358 n. 23:

“Whether safeguards othér than prior authorization by- a magistrate would satisfy the Fourth Amendment in a situation involving the national-security . . 7 .”

The determination of this question requires the essential Fourth .Amendment inquiry into .the “reasonableness” of the search and seizure in question, and the way in which that “reasonableness” derives content and mean*310ing through reference to the warrant ulause. Coolidge v. New Hampshire, 403 U. S. 443, 473-84 (1971).

We begin the inquiry by noting that the President of the United States has the fundamental duty, under Art. II, § 1, of the Constitution, to “preserve, protect and defend the Constitution of the United States.” Implicit in that duty is the power to protect our Government against those who. would subvert or overthrow it by unlawful means. In the discharge of this duty, the President — through the Attorney General— may find it necessary to employ electronic surveillance to obtain intelligence information on the plans of those who plot unlawful acts against the Government.9 The use of such surveillance in internal security cases has been sanctioned more or less continuously by various Presidents and Attorneys General since July 1946.10 *311Herbert Brownell, Attorney General under President Eisenhower, urged the use of electronic surveillance both in internal and international security matters on the grounds that those acting against the Government

“turn to the telephone to carry on their intrigue. The success of their plans frequently rests upon piecing together shreds of information received from many sources and many- nests. The participants in the conspiracy are often dispersed and stationed in various strategic positions in government and industry throughout the country.”11

Though the Government and respondents debate their seriousness and magnitude, threats and acts of sabotage against the Government exist in sufficent number to justify investigative powers with respect to them.12 The covertness and complexity of potential unlawful con*312duct against the Government and the necessary dependency of many conspirators upon the telephone make electronic surveillance an effective investigatory instrument in certain circumstances. The marked acceleration in technological developments and sophistication in their use have resulted in new techniques for the planning, commission, and concealment of criminal activities. It would be contrary to the public interest for Government to deny to itself the prudent and lawful employment of those very techniques which are employed against the Government and its law-abiding citizens.

It has been said that “[t]he most basic' function of any government is to provide for the security of the individual and of his property.” Miranda v. Arizona, 384 U. S. 436, 539 (1966) (White, J., dissenting). And unless Government safeguards its own capacity to function and to preserve the security of its people, society itself could become so disordered that all rights' and liberties would be endangered. As Chief Justice Hughes reminded us in Cox v. New Hampshire, 312 U. S. 569, 574 (1941):

“Civil liberties, as guaranteed by the Constitution, imply the existence of an organized society maintaining public order without which liberty itself would be lost in the excesses of unrestrained' abuses.”

But a recognition of these elementary truths does not make the employment by Government of electronic surveillance a welcome development — even when employed with restraint' and under judicial supervision. There is, understandably, a deep-seated uneasiness and apprehension that this capability will be used to intrude upon cherished privacy of law-abiding citizens.13 We *313look to the Bill of Rights to safeguard this privacy. Though physical entry of the home is the chief evil against which the wording of the Fourth Amendment is directed, its broader spirit, now shields private speech from unreasonable surveillance. Katz v. United States, supra; Berger v. New York, supra; Silverman v. United States, 365 U. S. 505 (1961). Our decision in Katz refused to lock the Fourth Amendment into • instances of actual physical trespass. Rather, the Amendment governs “not only the seizure of tangible items, but extends'as well to the recording of oral statements . . . without any ‘technical trespass under . . . local property law.’ ” Katz, supra, at 353. That decision implicitly recognized that the broad and unsuspected governmental incursions into conversational privacy which electronic surveillance entails14 necessitate the application of Fourth Amendment safeguards.

National security cases, moreover, often reflect a convergence of First and Fourth Amendment values not present in cases of “ordinary” crime. Though the investigative duty of the executive may be stronger in such cases, so also is there greater jeopardy to constitutionally protected speech. “Historically the struggle for freedom of speech and press in England was bound up with the issue of the scope of the search and seizure *314power,” Marcus v. Search Warrant, 367 U. S. 717, 724 (1961). History abundantly documents the tendency of Government — however benevolent and benign its motives — to view with suspicion those who most fervently dispute its policies. Fourth Amendment protections become the more necessary when the targets of official surveillance may be those suspected of unorthodoxy in their political beliefs. The danger to political dissent is acute where the Government attempts to act under so vague a concept as the power to protect “domestic security.” Given the difficulty of defining the domestic security, interest, the danger of abuse in acting to protect that interest becomes apparent. Senator Hart addressed this dilemma in the floor debate on § 2511 (3):

“As I read it — and this is my fear — we are saying that the President, on his motion, could declare— name your favorite poison — draft dodgers, Black Muslims, the Ku Klux Klan, or civil rights activists to be a clear and present danger to. the structure or existence of the Government.” 15

The price of lawful public dissent must not be a dread of subjection to an unchecked surveillance power. Nor must the fear of unauthorized official eavesdropping deter vigorous citizen.dissent and discussion of Government action in private conversation. For private dissent, no less than open public discourse, is essential to our free society.

Ill

As the Fourth Amendment is not absolute in its terms, our task is to examine and balance the basic values at stake in this case: the duty of Government *315to protect the domestic security, and the potential danger posed by unreasonable surveillance to individual privacy and free expression. If the legitimate need of Government to. safeguard domestic security requires the use of electronic surveillance, the question is whether the needs of citizens for privacy and free expression may not be better protected by requiring a warrant before such surveillance, is undertaken; We must also ask whether a warrant requirement would unduly frustrate; the. efforts of Government to protect itself from acts of subversion and overthrow, directed against it.

Though the Fourth Amendment speaks broadly of ‘unreasonable searches and seizures,” the definition of “reasonableness”' turns, at least in part, on the more specific commands of the warrant clarise. Some have argued that “[t]he relevant'.test is hot whether it is reasonable to procure á search warrant, but whethér the search was reasonable,”. United States v. Rabinowitz, 330 U. S. 56, 66 (1950).16 This view, however, overlooks the second clause of the Amendment. The warrant clause of the Fourth Amendment is not dead language. Rather, it has been.

“a valued part of our constitutional law for decades, and it has determined the result in scores and scores' of cases in courts all over this country. It is riot an inconvenience to be somehow ‘weighed’ against the claims of, police efficiency. It is, or should *316-be,- an- important working part of our machinery of government, operating as a matter of course to check the - ‘well-intentioned but mistakenly overzealous executive officers’. who are a part of any system of law enforcement.” Coolidge v. New Hampshire, 403 U. S., at 481.

See also United States v. Rabinowitz, supra, at 68 (Frankfurter, J.,, dissenting); Davis y. United States, 328 U. S. 582, 604 (1946) (Frankfurter, J., dissenting):

Over two centuries ago, Lord Mansfield held that common-law principles prohibited warrants that ordered the' arrest of unnamed individuals who the. officer might conclude were guilty, of seditious libel. “It is not fit,” . said Mansfield, “that the receiving. oi- judging of the. information should be left to the discretion of . the. officer. The magistrate ought to . judge;’ and should . give certain directions to the officer.” Leach v. Three of the King’s Messengers, 19 How. St. Tr. 1001, 1027 (1765).

• Lord Mansfield’s formulation touches' the very heart of the Fourth Amendment directive: that, where practical, a governmental search,and seizure should repre- ' sent both the efforts of the officer to gather evidence of .wrongful acts and the judgment of the magistrate that the collected evidence is sufficient to justify invasion of a citizen’s private premises or conversation.' Inherent in the concept of a warrant is its issúance by a “neutral and detached, magistrate.” Coolidge v. New Hampshire, supra, at 453; Katz v. United States, supra, at 356. The further requirement of “probable cause” instructs the magistrate that baseless searches shall not proceed.

These Fourth Amendment freedoms cannot properly be guaranteed if domestic security surveillances may be' conducted solely .within the discretion of the Execu*317tive Branch. The Fourth Amendment does not contemplate the executive officers of .Government as neutral and disinterested magistrates. . Their duty and responsibility are to enforce the- laws, to investigate, and to prosecute. Katz v. United States, supra, at 359-360 (Douglas, J., concurring). But those charged with this investigative and prosecutorial duty should not be the sole judges of when to utilize constitutionally sensitive means in pursuing their tasks. The historical judgment, which the Fourth Amendment accepts, is that unreviewed executive discretion may yield too. readily to pressures to-obtain incriminating evidence and overlook potential invasions of privacy and protected speech.17

It may well be that, in the instant case, the Government’s surveillance of Plamondon’s conversations was a reasonable one which readily would have gained prior judicial approval. But this Court “has never sustained a search upon the sole ground that officers reasonably expected to .find evidence of a particular crime and voluntarily confined their activities, to the least intru-. sive means consistent with that end.” Katz, supra, at 356-35.7. The Fourth Amendment contemplates a prior judicial judgment,18 not the risk that executive discretion may be reasonably exercised. This judicial role accords with our basic constitutional doctrine that individual freedoms will best be preserved through . a separation of powers and division of functions among the different branches and levels of Government. Harlan, Thoughts at a Dedication: Keeping the Judicial Function in Balance, 49 A. B. A. J. 943-944 (1963). The independent check upon executive discretion.is not *318satisfied, as the Government' argues, by “extremely limited” post-surveillance judicial review.19 Indeed, post-surveillance review would never reach the- surveillances which failed to result in prosecutions. Prior review by a neutral and detached' magistrate is the time-tested means of effectuating Fourth Amendment rights. Beck v. Ohio, 379 U. S. 89, 96 (1964).

It is true that there have been some exceptions to the warrant requirement. Chimel v. California, 395 U. S. 752 (1969); Terry v. Ohio, 392 U. S. 1 (1968); McDonald v. United States, 335 U. S. 451 (1948); Carroll v. United States, 267 U. S. 132 (1925). But those exceptions are few in number and carefully delineated, Katz, supra, at 357; in general, they serve the legitimate needs of law enforcement officers to protect their own well-being and preserve evidence from destruction. Even while carving out those exceptions, the Court has reaffirmed the principle that the “police must, whenever practicable, obtain advance judicial approval of searches and seizures through the warrant procedure,” Terry v. Ohio, supra, at 20; Chimel v. California, supra, at 762.

The Government argues that the special circumstances applicable to domestic, security, surveillances necessitate a further exception to the warrant requirement. It is urged that the requirement of prior judicial review would obstruct the President in the discharge of his constitutional duty to protect domestic, security. We are told further that these surveillances • are. directed- primarily to the collecting and maintaining of intelligence with *319respect to subversive forces/ and are not an attempt to gather evidence for specific criminal prosecutions. It is said that this type of surveillance should not be subject to traditional warrant requirements which were established to govern investigation' of criminal activity, not ongoing intelligence gathering. Brief for United States 15-16, 23-24; Reply Brief for United States 2-3.

The Government further insists that courts “as a practical matter would have neither-the knowledge nor the techniques necessary to determine whether there was probable cause to believe that surveillance was necessary to protect national security.”. These security problems, the Government contends, involve “a large number of complex and subtle factors” beyond the competence of courts to evaluate. Reply Brief for United States 4.

As a final reason for exemption from a warrant requirement, the Government believes that disclosure to a magistrate of all or even a significant portion of the information' involved in domestic security surveillances “would create serious potential dangers to -the national security and to the lives of informants and agents., . . .' Secrecy is the essential ingredient in intelligence gathering; requiring prior judicial authorization would create a greater 'danger of leaks . . . , because in addition to the judge, you have the clerk,-.the stenographer and some other officer like a law assistant or bailiff who may be apprised of the nature’ of the surveillance-.” Brief for United States 24-25:

These contentions in behalf .of a complete exemption from the warrant requirement, when urged on behalf of the President and the national security in -its domestic implications', merit the most careful consideration. We •certainly do not reject them lightly, especially at a time of worldwide ferment and when civil disorders in this country are more prevalent than iñ the less turbulent *320periods of our history.' There is, no doubt, pragmatic force to the Government’s position.

But we do not think a case has been made for the requested departure from Fourth Amendment standards. The circumstances, described do not justify complete exemption of domestic security surveillance from prior judicial scrutiny. Official surveillance, whether its purpose be criminal investigation or ongoing intelligence gathering, risks infringement of constitutionally protected privacy of speech. Security surveillances are especially sensitive because of the inherent vagueness of the domestic security concept, the necessarily broad and continuing nature of intelligence gathering, and the temptation to utilize such surveillances to oversee political dissent. We recognize, as we have before, the constitutional basis, of the President’s domestic security role, but we think it must be exercised in a manner compatible with the Fourth Amendment. In this case w;e hold that this requires an appropriate prior warrant procedure.

We cannot accept the Government’s argument that internal security matters are too. subtle and complex for judicial evaluation. Courts regularly deal with the most difficult issues of our society. There is no reason to believe that federal judges will be insensitive to or uncomprehending of the issues involved in domestic security cases. Certainly courts can recognize, that domestic security surveillance involves-different considerations from the surveillance of “ordinary crime.” If the threat is too subtle or complex for our senior law enforcement officers to convey its significance to a court, one may question whether there is probable cause for surveillance.

Nor do we believe prior judicial approval will fracture the secrecy essential to official intelligence gathering. The- investigation 'of criminal activity has long *321involved imparting , sensitive information to judicial officers who have respected the confidentialities involved. Judges may be counted upon to. be especially conscious of security requirements in national security cases. Titie III of the Omnibus Crime Control and Safe Streets Act already has imposed this responsibility on the judiciary in connection with such crimes as espionage, sabotage, and treason, .§§ 2516 (l.)(a) and (c), each of which may involve domestic as well as foreign security threats. Moreover, a warrant application involves no public or adversary proceedings: it is an ex parte request before a. magistrate or judge; Whatever security dangers clerical and secretarial personnel may pose can be minimized by proper administrative measures, possibly to the point of allowing the Government itself to provide the necessary clerical assistance.

Thus, we conclude that the Government’s concerns do not justify departure in this case from the customary Fourth Amendment requirement of judicial approval prior to initiation of a search or surveillance. Although some added burden will be imposed upon the Attorney General, this inconvenience is justified in a free society to protect constitutional values. Nor do we think the Government’s domestic surveillance powers will be impaired to any significant degree. A prior warrant establishes presumptive validity of the surveillance and will minimize the burden of justification in post-surveillance judicial review. By no means of least importance will be the reassurance of the public generally that indiscriminate wiretapping and bugging of law-abiding citizens cannot occur.

IV

We emphasize, before concluding this opinion, the scope of our decision. As stated at the outset, this case involves only the domestic aspects of national security. We have not addressed, and express no opinion *322as to, the issues which may be involved with respect to activities of foreign powers or their agents.20 Nor does our decision rest on thé langi^age of § 2511 (3) or any other section of Title III of the Omnibus Crime Control and Safe Streets Act of 1968. That Act does not attempt to define or delineate the powers of the President to meet domestic threats to the national security.

Moreover, we do not hold that the same type of standards and procedures prescribed by Title III are necessarily applicable to this case. , We recognize that domestic security surveillance may involve different policy and practical considerations from the surveillance of “ordinary crime.” The gathering of security intelligence is often long range and involves the interrelation of various sources and types of information. The exact targets of such surveillance may be more difficult to identify than in surveillance operations against many types of crime specified in Title III. Often, too, the emphasis of domestic intelligence gathering is on the prevention of unlawful activity or the enhancement of the Government’s preparedness for some possible future crisis or emergency. Thus, the focus of domestic surveillance may be less precise than that directed against more conventional types of crime.

Given these potential distinctions between Title III criminal surveillances and those involving the domestic security, Congress may wish to. consider protective standards for the latter , which differ from those already prescribed for specified crimes in Title III. Different standards may be compatible with the Fourth Amend*323ment if they are reasonable both in relation to the legitimate need of Government for intelligence information and the protected rights of our citizens. For the warrant application may vary according to the governmental interest to be enforced and the nature of citizen rights deserving protection. As the 'Court said in Camara v. Municipal Court, 387 U. S. 523, 534-535 (1967):

“In cases in which the Fourth Amendment requires that a warrant to search be. obtained, ‘probable cause’ is the standard by which a particular decision -to search is tested against the constitutional mandate of reasonableness. . . . In determining whether a particular inspection is reasonable — -and thus in determining whether there is probable cause to issue a warrant for that inspection — the need for. the inspection must be weighed in terms of these reasonable goals of code enforcement.”

It may be that’ Congress, for example, would judge that the application and affidavit showing probable cause need. not follow the exact requirements of § 2518 but should allege other circumstances more appropriate to domestic security cases; that the request for prior court •authorization could, in sensitive cases, be made to. any member of a specially designated court (e. g., the District Court for the District of Columbia or the Court of Appeals for the District of Columbia Circuit); and that the time and reporting requirements need not be so strict as those in § 2518. ■

The above paragraph does not, -of course, attempt to guide the congressional judgment but rather to delineate the present scope of our own opinion. We do not attempt to detail the precise standards for domestic secu-. rity warrants any more than our decision in Katz sought to set the refined requirements for the specified criminal surveillances which now constitute Title III. We do *324hold, however, that prior judicial approval is required for the type .of domestic security surveillance involved in this case and that such approval may be made in accordance with such reasonable standards as the Congress may prescribe.

V

As the surveillance of Plamondon’s conversations was unlawful, because conducted without prior judicial approval, the courts below correctly held that Alderman v. United States, 394 U. S. 165 (1969), is controlling and that it requires disclosure to the accused of his own im-permissibly intercepted conversations. As stated in Alderman, “the trial court .can and should, where appropriate, place a defendant and his counsel under enforceable orders against unwarranted disclosure of thé materials which they may be entitled to inspect.” 394 U. S., at 185.21

The judgment of the Court of Appeals is hereby

Affirmed.

The Chief Justice concurs in the result.

Mr, Justice Rehnquist took no part in the consideration or decision of this case.

Mr. Justice Douglas,

concurring.

While I join in the opinion of the Court, I add these words in support of it.

This is an important phase in the campaign of the police and intelligence agencies to obtain exemptions from the Warrant Clause of the Fourth Amendment. For, due to the clandestine nature of electronic eavesdropping, the need is acute for placing on the Govern*325ment the heavy burden to show that “exigencies of the situation [make its] course imperative.” 1 Other abuses, such as the search incident to arrest, have been partly deterred by the threat of damage actions against offending officers,2 the risk of adverse publicity, or the possibility of . reform through the political process. These latter safeguards, however, áre ineffective against lawless wiretapping and “bugging” of which their victims are totally unaware. Moreover, ■ even the risk of exclusion of- tainted evidence would here appear to be of negligible deterrent value inasmuch as the United States frankly concedes' that the primary purpose of these searches is to fortify its intelligence collage rather than to accumulate evidence to support indictments and convictions. If the Warrant Clause were held inapplicable here, then the federal intelligence machine would literally enjoy unchecked discretion.

Here, federal agents wish to rummage for months on end through every conversation, no matter how intimate or personal, carried over selected telephone lines, simply to seize those few utterances which may add to their sense of the pulse of a domestic underground.

We are told that one national security wiretap lasted for 14 months and monitored over 900 conversations. Senator -Edward Kennedy found recently that “war-rantless devices accounted for an average of 78 to 209 days of listening per device, as compared with a 13-day per device average for those devices installed under court order.”3 He concluded that the Government’s *326revelations posed “the frightening possibility that the conversations of untold thousands of citizens of this country are being monitored on secret devices which no judge has authorized and which may remain in operation for months and perhaps years at a time.” 4 Even the most innocent and random caller who uses or telephones^ into a tapped line can become a flagged number in the Government’s data bank. See Laird v. Tatum, 1971 Term, No. 71-288.

Such gross invasions of privacy epitomize the very evil to which the Warrant Clause was directed. This' Court .has been the unfortunate witness to the hazards of police intrusions which did not receive prior sanction by independent magistrates. For example, in Weeks v. United States, 232 U. S. 383; Mapp v. Ohio, 367 U. S. 643; and Chimel v. California, 395 U. S. 752, entire homes were ransacked pursuant to warrantless searches.. Indeed, in Kremen v. United States, 353 U. S. 346, the entire contents óf a cabin, totaling more than 890 items (such as “1 Dish Rag”) 5. were seized incident to an arrest of its occupant' and were taken to San Francisco for study. by FBI agents. ' In a similar case, Von Cleef v. New *327Jersey, 395 U. S. 814, police, without a warrant, searched an arrestee’s house for three hours, eventually seizing “several thousand' articles; including books, magazines, catalogues, mailing lists, private correspondence (both open and unopened), photographs, drawings, and film.” Id., at 815. In Silverthorne Lumber Co. v. United.States, 251 U. S. 385, federal agents “without a shadow of authority” raided the offices of one of the petitioners (the proprietors of which had earlier been jailed) and “made a clean sweep of all the books, papers and documents found there.” Justice Holmes, for the Court, termed this tactic an “outrage.” Id., at 390, 391. In Stanford v. Texas, 379 U. S. 476, state police seized more than 2,000 items of literature, including the writings of Mr. Justice Black, pursuant to a general search warrant issued to inspect an alleged subversive’s home.

That “domestic security” is said to be involved here does not draw this case outside the mainstream of Fourth Amendmént law. Rather, the recurring desire of reigning officials to employ dragnet techniques to intimidate their critics lies at the core of that prohibition. For it was such excesses as the use of general warrants and the writs of assistance that led to the ratification of the Fourth Amendment. ' In Entick v. Carrington, 19 How. St. Tr. 1029, 95 Eng. Rep. 807, decided in 1765, one finds a striking parallel to the executive warrants utilized here. The Secretary of State had issued general executive warrants to his messengers authorizing them to roam about and to seize libelous material and libellants of the sovereign. Entick, a critic of the Crown, was the victim of one such general search during which his seditious publications were impounded. He brought a successful damage action for trespass against the messengers. The verdict was sustained on appeal. Lord Camden wrote that if such sweeping tactics were validated, then “the secret cabinets and bureaus of every *328subject in this kingdom will be thrown open to the search and inspection of a messenger, whenever the secretary of state shall think fit to charge, or even to suspect, a person to be the author, printer, or publisher of a seditious libel.” Id., at 1063. In a related and similar proceeding, Huckle v. Money, 2.Wils. K. B. 206, 207, 95 Eng. Rep. 768, 769 (1763), the same judge who presided over Entick’s appeal held for another victim of the same despotic practice, saying “[t]o enter a man’s, house by virtue of a nameless warrant, in order to procure evidence, is worse than the Spanish Inquisition ....” See also Wilkes v. Wood, 19 How. St. Tr. 1153, 98 Eng. Rep. 489 (1763). As early as Boyd v. United States, 116 U. S. 616, 626, and as recently as Stanford v. Texas, supra, at 485-486; Berger v. New York, 388 U. S. 41, 49-50; and Coolidge v. New Hampshire, supra, at 455 n. 9, the tyrannical invasions described and assailed in Entick, Huckle, and Wilkes, practices which also were endured by the colonists,'6 have been rec*329ognized ' as the primary abuses which ensured the Warrant Clausé a prominent place in our Bill of Rights. See J. Landynski, Search and Seizure and the Supreme Court '28-48 (1966). N. Lasson, The History and Development of the .Fourth Amendment to the United States Constitution 43-78 (1937); Note, Warrantless Searches-In Light of Chimel:. A Return To-The Original Understanding, 11 Ariz. L. Rev. 457, 460-476 (1969).

As illustrated by a flood of cases before us this Term, e. g., Laird v. Tatum, No. 71-288; Gelbard v. United States, No. 71-110; United States v. Egan, No. 71-263; United States v. Caldwell, No. 70-57; United States v. Gravel, No. 71-1026; Kleindienst v. Mandel, No. 71-16;. we are currently in the, throes of another national seizure of paranoia, resembling the hysteria which surrounded The Alien and Sedition. Acts, the Palmer Raids, and the McCarthy era. Those who register dissent or who petition their governments for redress are subjected to scrutiny by grand juries,7 by the FBI,8 or even by the military.9 Their associates are in*330terrogated. Their homes are bugged and their telephones are wiretapped. They are befriended by secret government informers.10 Their patriotism and loyalty are ques*331tioned.11 Senator Sam Ervin, who has chaired hearings on military surveillance of civilian dissidents, warns that “it is not an exaggeration to talk in terms of hundreds of thousands of . . . dossiers.” 12 Senator Kennedy, as méntioned supra, found “the frightening possibility that the conversations of untold thousands are being monitored on secret devices.” More than our privacy. is implicated. Also, at stake is the reach of the Government’s power to intimidate its critics.

When the Executive attempts to excuse these tactics as essential to its defense against internál subversion, we are obliged' to remind it, without apology, of this Court’s long commitment to the preservation of the Bill of. Eights from the corrosive environment of precisely such expedi*332ents.13 As Justice Brandéis said, concurring in Whitney v. California, 274 U. S. 357, 377: “Those who won our independence by revo’.ition were not cowards. They did not fear political change. They did not exalt order at the cost of liberty.” Chief Justice Warren put it this way in United States v. Bobel, 389 U. S. 258, 264: “[T]his concept of ‘national defense’ cannot be deemed an end in itself, justifying any .. . power designed to promote such a goal. Implicit in the term ‘national defense’ is the notion of defending those values and ideas which set this Nation apart. . . . It would indeed be ironic if, in the name of national defense, we would sanction the subversion of . . . those liberties . . . which [make] the defense of the Nation worthwhile.”

The Warrant Clause has stood as a barrier against intrusions by officialdom into the privacies of life. But if that barrier were lowered now to permit suspected subversives’ most intimate conversations to be pillaged then why could not their abodes or mail be secretly searched by the same authority? To defeat so'terrifying a claim of inherent power we need only stand by the enduring values served by the Fourth Amendment. As we stated last Term in Coolidge v. New Hampshire, 403 U. S. 443, 455: “In times of unrest, whether caused by crime or racial conflict or fear of internal subversion, -this basic law *333and the values that.it represents may appear unrealistic or ‘extravagant’ to some. But the values were those of the authors of our fundamental constitutional concepts. In times not altogether unlike 'our own they won ... a right of personal security against arbitrary intrusions .... If times have changed, reducing everyman’s scope , to do as . he pleases in an urban and industrial world,- the changes, have made the values served.by the Fourth Amendment more, not less, important.” We have as much, or more to fear from the erosion of our sense of privacy and independence by the omnipresent electronic ear of the Government as we do from the likelihood that fomenters of domestic upheaval will modify our form of governing.14

*334APPENDIX TO OPINION OF DOUGLAS, J., CONCURRING

FEDERAL WIRETAPPING AND BUGGING 1969-1970

Days in Number' Use Year Days in Use Minimum Maximum (Rounded) (Rounded) z a &■ a

1969 30 462 94 8,100 20,800

1970 180 2,363 113 8,100 22,600

Average Days in Use Per Device Court Executive Ordered Ordered Devices Ratio of Days Used Executive Ordered: Court Ordered

Minimum Devices Minimum Maximum 3 H •R h si r*

17.5* 3.4 15.4 86.2 221.3 13.1 71.7 200.0 * O CO W5 03 030 03 03 t — i i — (

*335Mr. Justice White,

concurring in the judgment.

This case arises out of a two-count indictment charging conspiracy to injure and injury to Government property. Count I charged Robert Plamondon and two codefend-ants with conspiring with a fourth person to injure Government property with dynamite. Count II charged Plamondon alone with dynamiting and injuring Government property in Ann Arbor, Michigan. The defendants moved to compel the United States to disclose, among other,things, any logs and records of electronic-surveillance directed at them,'at unindicted coconspirators, or at any premises of the defendants or coconspirators. They also moved for a hearing to determine, whether any electronic surveillance disclosed had tainted the evidence On which the grand jury indictment was based and which the Government intended to use at trial. They asked for dismissal of the indictment if such taint were determined to exist. Opposing the motion, the United States submitted an affidavit of the Attorney General of the United States disclosing that “[t]he defendant Pla-mondon has participated, in conversations which were overheard by Government agents who were monitoring wiretaps which were being employed to gather intelligence information deemed necessary to protect the nation from attempts of domestic organizations to attack and subvert the existing structure of the Government,”the wiretaps having been expressly approved by the Attorney General. The records of the intercepted conversations and copies of the memorandum reflecting the Attorney General’s approval were submitted under seal and solely for the Court’s in camera inspection.1

*336As characterized by the District Court, the position of the United States was that the electronic monitoring of Plamondon’s conversations without judicial warrant was a lawful. exercise of the power of the President to safeguard the national security. The District Court granted the motion of defendants, holding that the President had no constitutional power- to employ electronic surveillance without warrant to gather information about domestic organizations. Absent probable cause and judicial authorization, the challenged wiretap infringed Plamondon’s Fourth Amendment rights. The court ordered the Government to disclose to defendants the records of the .monitored conversations and directed that a hearing be held to determine the existence of taint either in the indictment or in the evidence to be introduced at trial.

The Government’s petition for mandamus to require the District Court to vacate its order was denied by the Court of Appeals. 444 F. 2d 651 (CA6 1971). That court held that the Fourth Amendment barred warrantless electronic surveillance of domestic organizations even if at the direction of the President. It agreed with the District Court that because the wiretaps involved were therefore constitutionally infirm, the United States must turn over to defendants the records of overheard conversations- for the purpose of determining whether the Government’s evidence was tainted.

I would affirm the Court of Appeals but on the statutory ground urged by defendant-respondents (Brief 115) without reaching or intimating any views with respect *337to the constitutional issue decided by both the District Court and the Court of Appeals.

Title III of the Omnibus Crime Control and Safe Streets Act of 1968, 18 U. S. C. §§ 2610-2520, forbids, under pain of criminal penalties and civil actions for damages, any wiretapping or eavesdropping not undertaken in accordance with specified procedures for obtaining judicial warrants authorizing the surveillance. Section 2511 (1) establishes a general prohibition against electronic eavesdropping “[ejxcept as otherwise specifically provided” in the statute. Later sections provide detailed procedures for judicial authorization of official interceptions of oral communications; when these procedures are followed the interception is not subject to the prohibitions of §2511 (1). Section 2511 (2), how-evér, specifies other situations in which the general prohibitions of § 2511 (1). do not apply. In addition, § 2511 (3) provides that:

“Nothing contained in this chapter or in section .605 of the Communications Act of 1934 (48 Stat. 1143; 47 U. S. C.. 605) shall limit the constitutional power of,the President to take such measures as he deems necessary to protect the Nation against actual or potential attack or other hostile acts of a foreign power, to obtain foreign intelligence information deemed essential to the security of the United States, or to protect national security information against foreign intelligence activities. Nor shall anything contained in this chapter be deemed to 'limit the constitutional power of the President to take such measures as he deems necessary to protect the United States against the overthrow of the Government by force or other unlawful means, or against any other clear and present danger to the structure or existence of the Government. The con*338tents of any wire or oral communication intercepted by authority of the President in the exercise of the foregoing powers may be received in evidence in any trial hearing, or other proceeding only where such interception was reasonable, and shall not be otherwise used or. disclosed except as is necessary to. implement that power.”

It is this subsection that lies at the heart of this case.

The interception here was without judicial warrant, it was hot covered by the provisions, of § 2511 (2) and it is too clear for argument that it- is illegal under § 2511 (1) unless it is saved by §2511 (3). The majority asserts that § 2511 (3) is a “disclaimer” but not an “exception.” But however,it is labeled, it is apparent from the face of the section and its legislative history that if this interception is one of those described in § 2511 (3j, it is not reached by the statutory ban bn unwarranted electronic eavesdropping.2

The. defendants in the District Court moved for the production of the logs, of any electronic surveillance to which they might have been subjected. "The Govern-*339melit responded that conversations of Plamondon had been intercepted but took the position that turnover of surveillance records was not necessary because the interception complied with the law. Clearly, for the Government to prevail it was necessary to demonstrate, first, that the interception involved was not subject to the statutory requirement of judicial approval for wiretapping because the surveillance was within the scope of § 2511 (3); and, secondly, if the -Act did not forbid the warrantless wiretap, that the-surveillance was consistent with the Fourth Amendment.

The United States has made no claim in this case that the statute may not constitutionally be applied to the surveillance at issue here.3 Nor has it denied that to *340comply with the Act the surveillance must either be supported by a warrant pr fall within the bounds of the exceptions provided by § 2511 (3). Nevertheless, as I read the opinions of-the District Court and the Court of Appeals, neither court stopped to., inquire whether the chair lenged interception was illegal under the statute but proceeded directly to the constitutional issue without adverting to the time-honored rule that courts should abjure constitutional issues except where necessary to decision of the case before them. Ashwander v. Tennessee Valley Authority, 297 U. S. 288, 346-348 (1936) (concurring opinion). Because I conclude that on the record before us the surveillance undertaken by the Government in this case was illegal under the statute itself, I find it unnecessary, and therefore improper, to consider or decide the constitutional questions which the courts below improvidently reached.

The threshold statutory question is simply put: Was the electronic surveillance undertaken by the Government in this case a measure- deemed necessary by the President to implement either the first or second branch of the exception carved out by § 2511 (3) to the general requirement of a warrant? .

The answer, it seems to me, must turn on the affidavit of the Attorney General offered by the United States in opposition to defendants’ motion to disclose surveillance records. It is apparent that there is nothing whatsoever in this affidavit suggesting that the surveillance was *341undertaken within the first branch of the § 2511 (3) exception, that is,- to protect against foreign attack, to gather foreign intelligence or to protect national security information. The sole assertion was that the monitoring at issue was employed to gather intelligence information “deemed necessary to protect the nation from attempts of domestic organizations to attack and subvert the existing structure of the Government.” App. 20.

Neither can I-conclude from this characterization that the wiretap employed here fell within the exception recognized by the second sentence of § 2511 (3); for it utterly fails to assume responsibility for the judgment that Congress demanded: that the surveillance was necessary to prevent overthrow by force or other unlawful means or that there was any other clear and present dangér to the structure or existence of the Government. The affidavit speaks.only of attempts to attack or subvert; it makes no reference to force or unlawfulness; it articulates no conclusion that the attempts involved any clear and present danger .to the existence or structure of the Government.

The shortcomings of the affidavit when. measured against § 2511 (3) are patent. Indeed, the United States in oral argument conceded no less. The specific inquiry put to Government counsel was: “Do you think the' affidavit, standing alone, satisfies the Safe Streets Act?” The Assistant Atterney General answered “No, sir. We do not rely upon the affidavit itself . . . .” Tr. of Oral -Arg. 15.4

Government ciounsel, however, seek to save their case by reference to the in camera exhibit submitted to the *342District Court to supplement - the Attorney General's affidavit.5- It is said that the exhibit includes the request for wiretap approval submitted to the Attorney General, that the request asserted the need to avert a clear and present danger to the structure and existence of the Government, and that the Attorney General endorsed his approval on the request.6 But' I am unconvinced that the mere endorsement of the Attorney General on the. request for approval submitted to him must be taken as the Attorney General’s own opinion that the wiretap was necessary to . avert a clear and present danger to the existence or structure of the Government *343when, in an affidavit later filed in court specifically characterizing the purposes of the interception and at least impliedly the grounds for his prior approval, the Attorney General said only that the tap was undertaken to secure intelligence thought necessary to protect against attempts to attack.and subvert the structure,of Government. If the Attorney General’s approval of the interception is to be given a judicially cognizable meaning different from the meaning he seems to have ascribed to it in his affidavit filed in court, there obviously must be further proceedings in the District Court.

Moreover, I am reluctant to proceed in the first instance to examine the in camera material and either sustain ór reject the. surveillance ■ as a necessary measure to avert the dangers referred to in. §2511(3). What Congress excepted from the warrant requirement was a surveillance which the President would assume responsibility for deeming an essential measure to protect against clear and present danger.. No judge can ■satisfy this congressional requirement.

Without the necessary threshold determination, the interception is, in my opinion, contrary to the terms of the statute'and subject therefore to the prohibition contained in § 2515 against the use of the fruits of the warrantless electronic surveillance as evidence at any trial.7

There remain two additional interrelated reasons for, net reaching the constitutional issue. First, even if it were determined that the Attorney General purported to *344authorize an electronic surveillance for purposes exempt irom the general provisions of the Act, there would remain the issue whether his discretion was properly authorized. The United States concedes that the act of the Attorney General authorizing a warrantless wiretap is subject to judicial review to some extent, Brief for United States 21-23, and it seems improvident to proceed to constitutional questions until it x& determined that the Act itself does not bar the interception here in question.

Second, and again on the assumption that the surveillance here involved-fell within the exception providec by §2511 (3), no constitutional issue need be reached in this case if the fruits of the wiretap were inadmissible on statutory grounds in the criminal proceedings pending against respondent Plamondon. Section 2511 (3) itself states that “[t]he contents of any wire or oral communication intercepted by authority of the President in the exercise of the foregoing powers may be received in evidence in any trial hearing, or other proceeding only where such interception was reasonable, and shall not be otherwise used or disclosed except as is necessary to implement that power.” (Emphasis added.) There has been no determination by the District Court that it would be reasonable to use the fruits of the wiretap against Plamondon or that it would be necessary to do so to implement the purposes for which the tap was authorized.

My own conclusion, again, is that, as long as non-constitutional, statutory grounds for excluding the evidence or its fruits have not been disposed of, it is improvident to reach the constitutional issue.

I would thus affirm the -judgment of the Court of Appeals unless the Court is prepared to reconsider the necessity for - an adversary, rather than an in camera, hearing with respect to taint. If in camera proceedings are sufficient and no taint is discerned by the judge, this case is over, whatever the legality of the tap.

*216Justice Rehnquist

delivered the opinion of the Court.

Respondents Lance and Susan Gates were indicted for violation of state drug laws after police officers, executing a search warrant, discovered marihuana and other contraband in their automobile and home. Prior to trial the Gateses moved to suppress evidence seized during this search. The Illinois Supreme Court affirmed the decisions of lower state courts granting the motion. 85 Ill. 2d 376, 423 N. E. 2d 887 (1981). ■ It held that the affidavit submitted in support of the State’s application for a warrant to search the Gateses’ prop*217erty was inadequate under this Court’s decisions in Aguilar v. Texas, 378 U. S. 108 (1964), and Spinelli v. United States, 393 U. S. 410 (1969).

We granted certiorari to consider the application of the Fourth Amendment to a magistrate’s issuance of a search warrant on the basis of a partially corroborated anonymous informant’s tip. 454 U. S. 1140 (1982). After receiving briefs and hearing oral argument on this question, however, we requested the parties to address an additional question:

“[Wjhether the rule requiring the exclusion at a criminal trial of evidence obtained in violation of the Fourth Amendment, Mapp v. Ohio, 367 U. S. 643 (1961); Weeks v. United States, 232 U. S. 383 (1914), should to any extent be modified, so as, for example, not to require the exclusion of evidence obtained in the reasonable belief that the search and seizure at issue was consistent with the Fourth Amendment.” 459 U. S. 1028 (1982).

We decide today, with apologies to all, that the issue we framed for the parties was not presented to the Illinois courts and, accordingly, do not address it. Rather, we consider the question originally presented in the petition for certiorari, and conclude that the Illinois Supreme Court read the requirements of our Fourth Amendment decisions too restrictively. Initially, however, we set forth our reasons for not addressing the question regarding modification of the exclusionary rule framed in our order of November 29,1982. Ibid.

HH

Our certiorari jurisdiction over decisions from state courts derives from 28 U. S. C. § 1257, which provides that “[f]inal judgments or decrees rendered by the highest court of a State in which a decision could be had, may be reviewed by the Supreme Court as follows: ... (3) By writ of certiorari, . . . where any title, right, privilege or immunity is specially set up or claimed under the Constitution, treaties or statutes *218of... the United States.” The provision derives, albeit with important alterations, see, e. g., Act of Dec. 23, 1914, ch. 2, 38 Stat. 790; Act of June 25, 1948, § 1257, 62 Stat. 929, from the Judiciary Act of 1789, § 25, 1 Stat. 85.

Although we have spoken frequently on the meaning of §1257 and its predecessors, our decisions are in some respects not entirely clear. We held early on that § 25 of the Judiciary Act of 1789 furnished us with no jurisdiction unless a federal question had been both raised and decided in the state court below. As Justice Story wrote in Crowell v. Randell, 10 Pet. 368, 392 (1836): “If both of these requirements do not appear on the record, the appellate jurisdiction fails.” See also Owings v. Norwood’s Lessee, 5 Cranch 344 (1809).1

More recently, in McGoldrick v. Compagnie Generale Transatlantique, 309 U. S. 430, 434-435 (1940), the Court observed:

“But it is also the settled practice of this Court, in the exercise of its appellate jurisdiction, that it is only in exceptional cases, and then only in cases coming from the federal courts, that it considers questions urged by a petitioner or appellant not pressed or passed upon in the courts below.... In cases coming here from state courts in which a state statute is assailed as unconstitutional, there are reasons of peculiar force which should lead us to refrain from deciding questions not presented or decided in the highest court of the state whose judicial action we are called upon to review. Apart from the *219reluctance with which every court should proceed to set aside legislation as unconstitutional on grounds not properly presented, due regard for the appropriate relationship of this Court to state courts requires us to decline to consider and decide questions affecting the validity of state statutes not urged or considered there. It is for these reasons that this Court, where the constitutionality of a statute has been upheld in the state court, consistently refuses to consider any grounds of attack not raised or decided in that court.”

Finally, the Court seemed to reaffirm the jurisdictional character of the rule against our deciding claims “not pressed nor passed upon” in state court in State Farm Mutual Automobile Ins. Co. v. Duel, 324 U. S. 154, 160 (1945), where we explained that “[sjince the [State] Supreme Court did not pass on the question, we may not do so.” See also Hill v. California, 401 U. S. 797, 805-806 (1971).

Notwithstanding these decisions, however, several of our more recent cases have treated the so-called “not pressed or passed upon below” rule as merely a prudential restriction. In Terminiello v. Chicago, 337 U. S. 1 (1949), the Court reversed a state criminal conviction on a ground not urged in state court, nor even in this Court. Likewise, in Vachon v. New Hampshire, 414 U. S. 478 (1974), the Court summarily reversed a state criminal conviction on the ground, not raised in state court, or here, that it had been obtained in violation of the Due Process Clause of the Fourteenth Amendment. The Court indicated in a footnote, id., at 479, n. 3, that it possessed discretion to ignore the failure to raise in state court the question on which it decided the case.

In addition to this lack of clarity as to the character of the “not pressed or passed upon below” rule, we have recognized that it often may be unclear whether the particular federal question presented in this Court was raised or passed upon below. In Dewey v. Des Moines, 173 U. S. 193, 197-198 (1899), the fullest treatment of the subject, the Court said *220that “[i]f the question were only an enlargement of the one mentioned in the assignment of errors, or if it were so connected with it in substance as to form but another ground or reason for alleging the invalidity of the [lower court’s] judgment, we should have no hesitation in holding the assignment sufficient to permit the question to be now raised and argued. Parties are not confined here to the same arguments which were advanced in the courts below upon a Federal question there discussed.”2 We have not attempted, and likely would not have been able, to draw a clear-cut line between cases involving only an “enlargement” of questions presented below and those involving entirely new questions.

The application of these principles in the instant case is not entirely straightforward. It is clear in this case that respondents expressly raised, at every level of the Illinois judicial system, the claim that the Fourth Amendment had been violated by the actions of the Illinois police and that the evidence seized by the officers should be excluded from their trial. It also is clear that the State challenged, at every level of the Illinois court system, respondents’ claim that the substantive requirements of the Fourth Amendment had been violated. The State never, however, raised or addressed the question whether the federal exclusionary rule should be modified in any respect, and none of the opinions of the *221Illinois courts give any indication that the question was considered.

The case, of course, is before us on the State’s petition for a writ of certiorari. Since the Act of Dec. 23, 1914, ch. 2, 38 Stat. 790, jurisdiction has been vested in this Court to review state-court decisions even when a claimed federal right has been upheld. Our prior decisions interpreting the “not pressed or passed on below” rule have not, however, involved a State’s failure to raise a defense to a federal right or remedy asserted below. As explained below, however, we can see no reason to treat the State’s failure to have challenged an asserted federal claim differently from the failure of the proponent of a federal claim to have raised that claim.

We have identified several purposes underlying the “not pressed or passed upon” rule: for the most part, these are as applicable to the State’s failure to have opposed the assertion of a particular federal right, as to a party’s failure to have asserted the claim. First, “[questions not raised below are those on which the record is very likely to be inadequate since it certainly was not compiled with those questions in mind.” Cardinale v. Louisiana, 394 U. S. 437, 439 (1969). Exactly the same difficulty exists when the State urges modification of an existing constitutional right or accompanying remedy. Here, for example, the record contains little, if anything, regarding the subjective good faith of the police officers that searched the Gateses’ property — which might well be an important consideration in determining whether to fashion a good-faith exception to the exclusionary rule. Our consideration of whether to modify the exclusionary rule plainly would benefit from a record containing such facts.

Likewise, “due regard for the appropriate relationship of this Court to state courts,” McGoldrick v. Compagnie Generale Transatlantique, 309 U. S., at 434-435, demands that those courts be given an opportunity to consider the constitutionality of the actions of state officials, and, equally important, proposed changes in existing remedies for uncon*222stitutional actions. Finally, by requiring that the State first argue to the state courts that the federal exclusionary rule should be modified, we permit a state court, even if it agrees with the State as a matter of federal law, to rest its decision on an adequate and independent state ground. See Cardinale, supra, at 439. Illinois, for example, adopted an exclusionary rule as early as 1923, see People v. Brocamp, 307 Ill. 448, 138 N. E. 728 (1923), and might adhere to its view even if it thought we would conclude that the federal rule should be modified. In short, the reasons supporting our refusal to hear federal claims not raised in state court apply with equal force to the State’s failure to challenge the availability of a well-settled federal remedy. Whether the “not pressed or passed upon below” rule is jurisdictional, as our earlier decisions indicate, see supra, at 217-219, or prudential, as several of our later decisions assume, or whether its character might be different in cases like this from its character elsewhere, we need not decide. Whatever the character of the rule may be, consideration of the question presented in our order of November 29, 1982, would be contrary to the sound justifications for the “not pressed or passed upon below” rule, and we thus decide not to pass on the issue.

The fact that the Illinois courts affirmatively applied the federal exclusionary rule — suppressing evidence against respondents — does not affect our conclusion. In Morrison v. Watson, 154 U. S. 111 (1894), the Court was asked to consider whether a state statute impaired the plaintiff in error’s contract with the defendant in error. It declined to hear the case because the question presented here had not been pressed or passed on below. The Court acknowledged that the lower court’s opinion had restated the conclusion, set forth in an earlier decision of that court, that the state statute did not impermissibly impair contractual obligations. Nonetheless, it held that there was no showing that “there was any real contest at any stage of this case upon the point,” id., at 115, and that without such a contest, the routine restate*223ment and application of settled law by an appellate court did not satisfy the “not pressed or passed upon below” rule. Similarly, in the present case, although the Illinois courts applied the federal exclusionary rule, there was never “any real contest” upon the point. The application of the exclusionary rule was merely a routine act, once a violation of the Fourth Amendment had been found, and not the considered judgment of the Illinois courts on the question whether application of a modified rule would be warranted on the facts of this case. In such circumstances, absent the adversarial dispute necessary to apprise the state court of the arguments for not applying the exclusionary rule, we will not consider the question whether the exclusionary rule should be modified.

Likewise, we do not believe that the State’s repeated opposition to respondents’ substantive Fourth Amendment claims suffices to have raised the question whether the exclusionary rule should be modified. The exclusionary rule is “a judicially created remedy designed to safeguard Fourth Amendment rights generally” and not “a personal constitutional right of the party aggrieved.” United States v. Calandra, 414 U. S. 338, 348 (1974). The question whether the exclusionary rule’s remedy is appropriate in a particular context has long been regardéd as an issue separate from the question whether the Fourth Amendment rights of the party seeking to invoke the rule were violated by police conduct. See, e. g., United States v. Havens, 446 U. S. 620 (1980); United States v. Ceccolini, 435 U. S. 268 (1978); United States v. Calandra, supra; Stone v. Powell, 428 U. S. 465 (1976). Because of this distinction, we cannot say that modification or abolition of the exclusionary rule is “so connected with [the substantive Fourth Amendment right at issue] as to form but another ground or reason for alleging the invalidity” of the judgment. Dewey v. Des Moines, 173 U. S., at 197-198. Rather, the rule’s modification was, for purposes of the “not pressed or passed upon below” rule, a separate claim that had to be specifically presented to the state courts.

*224Finally, weighty prudential considerations militate against our considering the question presented in our order of November 29, 1982. The extent of the continued vitality of the rules that have developed from our decisions in Weeks v. United States, 232 U. S. 383 (1914), and Mapp v. Ohio, 367 U. S. 643 (1961), is an issue of unusual significance. Sufficient evidence of this lies just in the comments on the issue that Members of this Court recently have made, e. g., Bivens v. Six Unknown Fed. Narcotics Agents, 403 U. S. 388, 415 (1971) (Burger, C. J., dissenting); Coolidge v. New Hampshire, 403 U. S. 443, 490 (1971) (Harlan, J., concurring); id., at 502 (Black, J., dissenting); Stone v. Powell, supra, at 537-539 (White, J., dissenting); Brewer v. Williams, 430 U. S. 387, 413-414 (1977) (Powell, J., concurring); Robbins v. California, 453 U. S. 420, 437, 443-444 (1981) (Rehnquist, J., dissenting). Where difficult issues of great public importance are involved, there are strong reasons to adhere scrupulously to the customary limitations on our discretion. By doing so we “promote respect... for the Court’s adjudicatory process [and] the stability of [our] decisions.” Mapp v. Ohio, 367 U. S., at 677 (Harlan, J., dissenting). Moreover, fidelity to the rule guarantees that a factual record will be available to us, thereby discouraging the framing of broad rules, seemingly sensible on one set of facts, which may prove ill-considered in other circumstances. In Justice Harlan’s words, adherence to the rule lessens the threat of “untoward practical ramifications,” id., at 676 (dissenting opinion), not foreseen at the time of decision. The public importance of our decisions in Weeks and Mapp and the emotions engendered by the debate surrounding these decisions counsel that we meticulously observe our customary procedural rules. By following this course, we promote respect for the procedures by which our decisions are rendered, as well as confidence in the stability of prior decisions. A wise exercise of the powers confided in this Court dictates that we reserve for another day the question whether the exclusionary rule should be modified.

*225l-H H — (

We now turn to the question presented in the State’s original petition for certiorari, which requires us to decide whether respondents’ rights under the Fourth and Fourteenth Amendments were violated by the search of their car and house. A chronological statement of events usefully introduces the issues at stake. Bloomingdale, Ill., is a suburb of Chicago located in Du Page County. On May 3, 1978, the Bloomingdale Police Department received by mail an anonymous handwritten letter which read as follows:

“This letter is to inform you that you have a couple in your town who strictly make their living on selling drugs. They are Sue and Lance Gates, they live on Greenway, off Bloomingdale Rd. in the condominiums. Most of their buys are done in Florida. Sue his wife drives their car to Florida, where she leaves it to be loaded up with drugs, then Lance flys down and drives it back. Sue flys back after she drops the car off in Florida. May 3 she is driving down there again and Lance will be flying down in a few days to drive it back. At the time Lance drives the car back he has the trunk loaded with over $100,000.00 in drugs. Presently they have over $100,000.00 worth of drugs in their basement.

“They brag about the fact they never have to work, and make their entire living on pushers.

“I guarantee if you watch them carefully you will make a big catch. They are friends with some big drugs dealers, who visit their house often.

“Lance & Susan Gates

“Greenway

“in Condominiums”

The letter was referred by the Chief of Police of the Bloomingdale Police Department to Detective Mader, who decided to pursue the tip. Mader learned, from the office of the Illinois Secretary of State, that an Illinois driver’s license had *226been issued to one Lance Gates, residing at a stated address in Bloomingdale. He contacted a confidential informant, whose examination of certain financial records revealed a more recent address for the Gateses, and he also learned from a police officer assigned to O'Hare Airport that “L. Gates” had made a reservation on Eastern Airlines Flight 245 to West Palm Beach, Fla., scheduled to depart from Chicago on May 5 at 4:15 p. m.

Mader then made arrangements with an agent of the Drug Enforcement Administration for surveillance of the May 5 Eastern Airlines flight. The agent later reported to Mader that Gates had boarded the flight, and that federal agents in Florida had observed him arrive in West Palm Beach and take a taxi to the nearby Holiday Inn. They also reported that Gates went to a room registered to one Susan Gates and that, at 7 o’clock the next morning, Gates and an unidentified woman left the motel in a Mercury bearing Illinois license plates and drove northbound on an interstate highway frequently used by travelers to the Chicago area. In addition, the DEA agent informed Mader that the license plate number on the Mercury was registered to a Hornet station wagon owned by Gates. The agent also advised Mader that the driving time between West Palm Beach and Bloomingdale was approximately 22 to 24 hours.

Mader signed an affidavit setting forth the foregoing facts, and submitted it to a judge of the Circuit Court of Du Page County, together with a copy of the anonymous letter. The judge of that court thereupon issued a search warrant for the Gateses' residence and for their automobile. The judge, in deciding to issue the warrant, could have determined that the modus operandi of the Gateses had been substantially corroborated. As the anonymous letter predicted, Lance Gates had flown from Chicago to West Palm Beach late in the afternoon of May 5th, had checked into a hotel room registered in the name of his wife, and, at 7 o’clock the following morning, had headed north, accompanied by an unidentified woman, *227out of West Palm Beach on an interstate highway used by travelers from South Florida to Chicago in an automobile bearing a license plate issued to him.

At 5:15 a. m. on March 7, only 36 hours after he had flown out of Chicago, Lance Gates, and his wife, returned to their home in Bloomingdale, driving the car in which they had left West Palm Beach some 22 hours earlier. The Bloomingdale police were awaiting them, searched the trunk of the Mercury, and uncovered approximately 350 pounds of marihuana. A search of the Gateses’ home revealed marihuana, weapons, and other contraband. The Illinois Circuit Court ordered suppression of all these items, on the ground that the affidavit submitted to the Circuit Judge failed to support the necessary determination of probable cause to believe that the Gateses’ automobile and home contained the contraband in question. This decision was affirmed in turn by the Illinois Appellate Court, 82 Ill. App. 3d 749, 403 N. E. 2d 77 (1980), and by a divided vote of the Supreme Court of Illinois. 85 Ill. 2d 376, 423 N. E. 2d 887 (1981).

The Illinois Supreme Court concluded — and we are inclined to agree — that, standing alone, the anonymous letter sent to the Bloomingdale Police Department would not provide the basis for a magistrate’s determination that there was probable cause to believe contraband would be found in the Gateses’ car and home. The letter provides virtually nothing from which one might conclude that its author is either honest or his information reliable; likewise, the letter gives absolutely no indication of the basis for the writer’s predictions regarding the Gateses’ criminal activities. Something more was required, then, before a magistrate could conclude that there was probable cause to believe that contraband would be found in the Gateses’ home and car. See Aguilar v. Texas, 378 U. S., at 109, n. 1; Nathanson v. United States, 290 U. S. 41 (1933).

The Illinois Supreme Court also properly recognized that Detective Mader’s affidavit might be capable of supplement*228ing the anonymous letter with information sufficient to permit a determination of probable cause. See Whiteley v. Warden, 401 U. S. 560, 567 (1971). In holding that the affidavit in fact did not contain sufficient additional information to sustain a determination of probable cause, the Illinois court applied a “two-pronged test,” derived from our decision in Spinelli v. United States, 393 U. S. 410 (1969).3 The Illinois Supreme Court, like some others, apparently understood Spinelli as requiring that the anonymous letter satisfy each of two independent requirements before it could be relied on. 85 Ill. 2d, at 383, 423 N. E. 2d, at 890. According to this view, the letter, as supplemented by Mader’s affidavit, first had to adequately reveal the “basis of knowledge” of the letterwriter — the particular means by which he came by the information given in his report. Second, it had to pro*229vide facts sufficiently establishing either the “veracity” of the affiant’s informant, or, alternatively, the “reliability” of the informant’s report in this particular case.

The Illinois court, alluding to an elaborate set of legal rules that have developed among various lower courts to enforce the “two-pronged test,”4 found that the test had not been satisfied. First, the “veracity” prong was not satisfied because, “[t]here was simply no basis [for] concluding] that the anonymous person [who wrote the letter to the Bloomingdale Police Department] was credible.” Id., at 385, 423 N. E. 2d, at 891. The court indicated that corroboration by police of details contained in the letter might never satisfy the “veracity” prong, and in any event, could not do so if, as in the present case, only “innocent” details are corroborated. Id., at 390, 423 N. E. 2d, at 893. In addition, the letter gave no indication of the basis of its writer’s knowledge of the *230Gateses’ activities. The Illinois court understood Spinelli as permitting the detail contained in a tip to be used to infer that the informant had a reliable basis for his statements, but it thought that the anonymous letter failed to provide sufficient detail to permit such an inference. Thus, it concluded that no showing of probable cause had been made.

We agree with the Illinois Supreme Court that an informant’s “veracity,” “reliability,” and “basis of knowledge” are all highly relevant in determining the value of his report. We do not agree, however, that these elements should be understood as entirely separate and independent requirements to be rigidly exacted in every case,5 which the opinion of the Supreme Court of Illinois would imply. Rather, as detailed below, they should be understood simply as closely intertwined issues that may usefully illuminate the commonsense, practical question whether there is “probable cause” to believe that contraband or evidence is located in a particular place.

Ill

This totality-of-the-circumstances approach is far more consistent with our prior treatment of probable cause6 than *231is any rigid demand that specific “tests” be satisfied by every informant’s tip. Perhaps the central teaching of our decisions bearing on the probable-cause standard is that it is a “practical, nontechnical conception.” Brinegar v. United States, 338 U. S. 160, 176 (1949). “In dealing with probable cause, ... as the very name implies, we deal with probabilities. These are not technical; they are the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.” Id., at 175. Our observation in United States v. Cortez, 449 U. S. 411, 418 (1981), regarding “particularized suspicion,” is also applicable to the probable-cause standard:

“The process does not deal with hard certainties, but with probabilities. Long before the law of probabilities was articulated as such, practical people formulated certain common-sense conclusions about human behavior; jurors as factfinders are permitted to do the same — and *232so are law enforcement officers. Finally, the evidence thus collected must be seen and weighed not in terms of library analysis by scholars, but as understood by those versed in the field of law enforcement.”

As these comments illustrate, probable cause is a fluid concept — turning on the assessment of probabilities in particular factual contexts — not readily, or even usefully, reduced to a neat set of legal rules. Informants’ tips doubtless come in many shapes and sizes from many different types of persons. As we said in Adams v. Williams, 407 U. S. 143, 147 (1972): “Informants’ tips, like all other clues and evidence coming to a policeman on the scene, may vary greatly in their value and reliability.” Rigid legal rules are ill-suited to an area of such diversity. “One simple rule will not cover every situation.” Ibid.7

*233Moreover, the “two-pronged test” directs analysis into two largely independent channels — the informant’s “veracity” or “reliability” and his “basis of knowledge.” See nn. 4 and 5, supra. There are persuasive arguments against according these two elements such independent status. Instead, they are better understood as relevant considerations in the totality-of-the-circumstances analysis that traditionally has guided probable-cause determinations: a deficiency in one may be compensated for, in determining the overall reliability of a tip, by a strong showing as to the other, or by some other indicia of reliability. See, e. g., Adams v. Williams, supra, at 146-147; United States v. Harris, 403 U. S. 573 (1971).

If, for example, a particular informant is known for the unusual reliability of his predictions of certain types of criminal activities in a locality, his failure, in a particular case, to thoroughly set forth the basis of his knowledge surely should not serve as an absolute bar to a finding of probable cause based on his tip. See United States v. Sellers, 483 F. 2d 37 (CA5 1973).8 Likewise, if an unquestionably honest citizen comes forward with a report of criminal activity — which if fabricated would subject him to criminal liability — we have found *234rigorous scrutiny of the basis of his knowledge unnecessary. Adams v. Williams, supra. Conversely, even if we entertain some doubt as to an informant’s motives, his explicit and detailed description of alleged wrongdoing, along with a statement that the event was observed firsthand, entitles his tip to greater weight than might otherwise be the case. Unlike a totality-of-the-circumstances analysis, which permits a balanced assessment of the relative weights of all the various indicia of reliability (and unreliability) attending an informant’s tip, the “two-pronged test” has encouraged an excessively technical dissection of informants’ tips,9 with undue at*235tention being focused on isolated issues that cannot sensibly be divorced from the other facts presented to the magistrate.

As early as Locke v. United States, 7 Cranch 339, 348 (1813), Chief Justice Marshall observed, in a closely related context: “[T]he term ‘probable cause,’ according to its usual acceptation, means less than evidence which would justify condemnation .... It imports a seizure made under circumstances which warrant suspicion.” More recently, we said that “the quanta ... of proof” appropriate in ordinary judicial proceedings are inapplicable to the decision to issue a warrant. Brinegar, 338 U. S., at 173. Finely tuned standards such as proof beyond a reasonable doubt or by a preponderance of the evidence, useful in formal trials, have no place in the magistrate’s decision. While an effort to fix some general, numerically precise degree of certainty corresponding to “probable cause” may not be helpful, it is clear that “only the probability, and not a prima facie showing, of criminal activity is the standard of probable cause.” Spinelli, 393 U. S., at 419. See Model Code of Pre-Arraignment Procedure §210.1(7) (Prop. Off. Draft 1972); 1 W. LaFave, Search and Seizure § 3.2(e) (1978).

We also have recognized that affidavits “are normally drafted by nonlawyers in the midst and haste of a criminal investigation. Technical requirements of elaborate specificity once exacted under common law pleadings have no proper place in this area.” United States v. Ventresca, 380 U. S. 102, 108 (1965). Likewise, search and arrest warrants long have been issued by persons who are neither lawyers nor judges, and who certainly do not remain abreast of each judicial refinement of the nature of “probable cause.” See Shadwick v. City of Tampa, 407 U. S. 345, 348-350 (1972). The rigorous inquiry into the Spinelli prongs and the complex superstructure of evidentiary and analytical rules that some have seen implicit in our Spinelli decision, cannot be reconciled with the fact that many warrants are — quite properly, 407 U. S., at 348-350 — issued on the basis of nontechnical, *236common-sense judgments of laymen applying a standard less demanding than those used in more formal legal proceedings. Likewise, given the informal, often hurried context in which it must be applied, the “built-in subtleties,” Stanley v. State, 19 Md. App. 507, 528, 313 A. 2d 847, 860 (1974), of the “two-pronged test” are particularly unlikely to assist magistrates in determining probable cause.

Similarly, we have repeatedly said that after-the-fact scrutiny by courts of the sufficiency of an affidavit should not take the form of de novo review. A magistrate's “determination of probable cause should be paid great deference by reviewing courts.” Spinelli, supra, at 419. “A grudging or negative attitude by reviewing courts toward warrants,” Ventresca, 380 U. S., at 108, is inconsistent with the Fourth Amendment’s strong preference for searches conducted pursuant to a warrant; “courts should not invalidate warrants] by interpreting affidavits] in a hypertechnical, rather than a commonsense, manner.” Id., at 109.

If the affidavits submitted by police officers are subjected to the type of scrutiny some courts have deemed appropriate, police might well resort to warrantless searches, with the hope of relying on consent or some other exception to the Warrant Clause that might develop at the time of the search. In addition, the possession of a warrant by officers conducting an arrest or search greatly reduces the perception of unlawful or intrusive police conduct, by assuring “the individual whose property is searched or seized of the lawful authority of the executing officer, his need to search, and the limits of his power to search.” United States v. Chadwick, 433 U. S. 1, 9 (1977). Reflecting this preference for the warrant process, the traditional standard for review of an issuing magistrate’s probable-cause determination has been that so long as the magistrate had a “substantial basis for . . . concluding]” that a search would uncover evidence of wrongdoing, the Fourth Amendment requires no more. Jones v. United States, 362 U. S. 257, 271 (1960). See United States v. *237Harris, 403 U. S., at 577-583.10 We think reaffirmation of this standard better serves the purpose of encouraging recourse to the warrant procedure and is more consistent with our traditional deference to the probable-cause determinations of magistrates than is the “two-pronged test.”

Finally, the direction taken by decisions following Spinelli poorly serves “[t]he most basic function of any government”: “to provide for the security of the individual and of his property.” Miranda v. Arizona, 384 U. S. 436, 539 (1966) (White, J., dissenting). The strictures that inevitably accompany the “two-pronged test” cannot avoid seriously impeding the task of law enforcement, see, e. g., n. 9, supra. If, as the Illinois Supreme Court apparently thought, that test must be rigorously applied in every case, anonymous tips would be of greatly diminished value in police work. Ordinary citizens, like ordinary witnesses, see Advisory Committee’s Notes on Fed. Rule Evid. 701, 28 U. S. C. App., p. 570, generally do not provide extensive recitations of the basis of their everyday observations. Likewise, as the Illinois Supreme Court observed in this case, the veracity of persons supplying anonymous tips is by hypothesis largely unknown, and unknowable. As a result, anonymous tips seldom could survive a rigorous application of either of the Spinelli prongs. Yet, such tips, particularly when supplemented by *238independent police investigation, frequently contribute to the solution of otherwise “perfect crimes.” While a conscientious assessment of the basis for crediting such tips is required by the Fourth Amendment, a standard that leaves virtually no place for anonymous citizen informants is not.

For all these reasons, we conclude that it is wiser to abandon the “two-pronged test” established by our decisions in Aguilar and Spinelli.11 In its place we reaffirm the totality-of-the-circumstances analysis that traditionally has informed probable-cause determinations. See Jones v. United States, supra; United States v. Ventresca, 380 U. S. 102 (1965); Brinegar v. United States, 338 U. S. 160 (1949). The task of the issuing magistrate is simply to make a practical, commonsense decision whether, given all the circumstances set forth in the affidavit before him, including the “veracity” and “basis of knowledge” of persons supplying hearsay information, there is a fair probability that contraband or evidence of a crime will be found in a particular place. And the duty of a reviewing court is simply to ensure that the magistrate had a “substantial basis for . . . concluding]” that probable cause *239existed. Jones v. United States, 362 U. S., at 271. We are convinced that this flexible, easily applied standard will better achieve the accommodation of public and private interests that the Fourth Amendment requires than does the approach that has developed from Aguilar and Spinelli.

Our earlier cases illustrate the limits beyond which a magistrate may not venture in issuing a warrant. A sworn statement of an affiant that “he has cause to suspect and does believe” that liquor illegally brought into the United States is located on certain premises will not do. Nathanson v. United States, 290 U. S. 41 (1933). An affidavit must provide the magistrate with a substantial basis for determining the existence of probable cause, and the wholly conclusory statement at issue in Nathanson failed to meet this requirement. An officer’s statement that “[a]ffiants have received reliable information from a credible person and do believe” that heroin is stored in a home, is likewise inadequate. Aguilar v. Texas, 378 U. S. 108 (1964). As in Nathanson, this is a mere conclusory statement that gives the magistrate virtually no basis at all for making a judgment regarding probable cause. Sufficient information must be presented to the magistrate to allow that official to determine probable cause; his action cannot be a mere ratification of the bare conclusions of others. In order to ensure that such an abdication of the magistrate’s duty does not occur, courts must continue to conscientiously review the sufficiency of affidavits on which warrants are issued. But when we move beyond the “bare bones” affidavits present in cases such as Nathanson and Aguilar, this area simply does not lend itself to a prescribed set of rules, like that which had developed from Spinelli. Instead, the flexible, common-sense standard articulated in Jones, Ventresca, and Brinegar better serves the purposes of the Fourth Amendment’s probable-cause requirement.

Justice Brennan’s dissent suggests in several places that the approach we take today somehow downgrades the *240role of the neutral magistrate, because Aguilar and Spinelli “preserve the role of magistrates as independent arbiters of probable cause . . . Post, at 287. Quite the contrary, we believe, is the case. The essential protection of the warrant requirement of the Fourth Amendment, as stated in Johnson v. United States, 333 U. S. 10 (1948), is in “requiring that [the usual inferences which reasonable men draw from evidence] be drawn by a neutral and detached magistrate instead of being judged by the officer engaged in the often competitive enterprise of ferreting out crime.” Id., at 13-14. Nothing in our opinion in any way lessens the authority of the magistrate to draw such reasonable inferences as he will from the material supplied to him by applicants for a warrant; indeed, he is freer than under the regime of Aguilar and Spinelli to draw such inferences, or to refuse to draw them if he is so minded.

The real gist of Justice Brennan’s criticism seems to be a second argument, somewhat at odds with the first, that magistrates should be restricted in their authority to make probable-cause determinations by the standards laid down in Aguilar and Spinelli, and that such findings “should not be authorized unless there is some assurance that the information on which they are based has been obtained in a reliable way by an honest or credible person.” Post, at 283. However, under our opinion magistrates remain perfectly free to exact such assurances as they deem necessary, as well as those required by this opinion, in making probable-cause determinations. Justice Brennan would apparently prefer that magistrates be restricted in their findings of probable cause by the development of an elaborate body of case law dealing with the “veracity” prong of the Spinelli test, which in turn is broken down into two “spurs” — the informant’s “credibility” and the “reliability” of his information, together with the “basis of knowledge” prong of the Spinelli test. See n. 4, supra. That such a labyrinthine body of judicial refinement bears any relationship to familiar definitions of *241probable cause is hard to imagine. As previously noted, probable cause deals “with probabilities. These are not technical; they are the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act "Brinegar v. United States, 338 U. S., at 175.

Justice Brennan’s dissent also suggests that “[w]ords such as ‘practical,’ ‘nontechnical,’ and ‘common sense,’ as used in the Court’s opinion, are but code words for an overly permissive attitude towards police practices in derogation of the rights secured by the Fourth Amendment.” Post, at 290. An easy, but not a complete, answer to this rather florid statement would be that nothing we know about Justice Rutledge suggests that he would have used the words he chose in Brinegar in such a manner. More fundamentally, no one doubts that “under our Constitution only measures consistent with the Fourth Amendment may be employed by government to cure [the horrors of drug trafficking],” post, at 290; but this agreement does not advance the inquiry as to which measures are, and which measures are not, consistent with the Fourth Amendment. “Fidelity” to the commands of the Constitution suggests balanced judgment rather than exhortation. The highest “fidelity” is not achieved by the judge who instinctively goes furthest in upholding even the most bizarre claim of individual constitutional rights, any more than it is achieved by a judge who instinctively goes furthest in accepting the most restrictive claims of governmental authorities. The task of this Court, as of other courts, is to “hold the balance true,” and we think we have done that in this case.

IV

Our decisions applying the totality-of-the-circumstances analysis outlined above have consistently recognized the value of corroboration of details of an informant’s tip by independent police work. In Jones v. United States, 362 U. S., at 269, we held that an affidavit relying on hearsay “is not to *242be deemed insufficient on that score, so long as a substantial basis for crediting the hearsay is presented.” We went on to say that even in making a warrantless arrest an officer “may rely upon information received through an informant, rather than upon his direct observations, so long as the informant’s statement is reasonably corroborated by other matters within the officer’s knowledge.” Ibid. Likewise, we recognized the probative value of corroborative efforts of police officials in Aguilar — the source of the “two-pronged test” — by observing that if the police had made some effort to corroborate the informant’s report at issue, “an entirely different case” would have been presented. Aguilar, 378 U. S., at 109, n. 1.

Our decision in Draper v. United States, 358 U. S. 307 (1959), however, is the classic case on the value of corroborative efforts of police officials. There, an informant named Hereford reported that Draper would arrive in Denver on a train from Chicago on one of two days, and that he would be carrying a quantity of heroin. The informant also supplied a fairly detailed physical description of Draper, and predicted that he would be wearing a light colored raincoat, brown slacks, and black shoes, and would be walking “real fast.” Id., at 309. Hereford gave no indication of the basis for his information.12

On one of the stated dates police officers observed a man matching this description exit a train arriving from Chicago; his attire and luggage matched Hereford’s report and he was *243walking rapidly. We explained in Draper that, by this point in his investigation, the arresting officer “had personally verified every facet of the information given him by Hereford except whether petitioner had accomplished his mission and had the three ounces of heroin on his person or in his bag. And surely, with every other bit of Hereford’s information being thus personally verified, [the officer] had ‘reasonable grounds’ to believe that the remaining unverified bit of Hereford’s information — that Draper would have the heroin with him — was likewise true,” id., at 313.

The showing of probable cause in the present case was fully as compelling as that in Draper. Even standing alone, the facts obtained through the independent investigation of Mader and the DEA at least suggested that the Gateses were involved in drug trafficking. In addition to being a popular vacation site, Florida is well known as a source of narcotics and other illegal drugs. See United States v. Mendenhall, 446 U. S. 544, 562 (1980) (Powell, J., concurring in part and concurring in judgment); DEA, Narcotics Intelligence Estimate, The Supply of Drugs to the U. S. Illicit Market From Foreign and Domestic Sources in 1980, pp. 8-9. Lance Gates’ flight to West Palm Beach, his brief, overnight stay in a motel, and apparent immediate return north to Chicago in the family car, conveniently awaiting him in West Palm Beach, is as suggestive of a prearranged drug run, as it is of an ordinary vacation trip.

In addition, the judge could rely on the anonymous letter, which had been corroborated in major part by Mader's efforts — just as had occurred in Draper.13 The Supreme Court *244of Illinois reasoned that Draper involved an informant who had given reliable information on previous occasions, while the honesty and reliability of the anonymous informant in this case were unknown to the Bloomingdale police. While this distinction might be an apt one at the time the Police Department received the anonymous letter, it became far less significant after Mader’s independent investigative work occurred. The corroboration of the letter’s predictions that the Gateses’ car would be in Florida, that Lance Gates would fly to Florida in the next day or so, and that he would drive the car north toward Bloomingdale all indicated, albeit not with certainty, that the informant’s other assertions also were true. “[Bjecause an informant is right about some things, he is more probably right about other facts,” Spinelli, 393 U. S., at 427 (White, J., concurring) — including the claim regarding the Gateses’ illegal activity. This may well not be the type of “reliability” or “veracity” necessary to satisfy some views of the “veracity prong” of Spinelli, but we think it suffices for the practical, common-sense judgment called for in making a probable-cause determination. It is enough, for purposes of assessing probable cause, that “[corroboration through other sources of information reduced the *245chances of a reckless or prevaricating tale,” thus providing “a substantial basis for crediting the hearsay.” Jones v. United States, 362 U. S., at 269, 271.

Finally, the anonymous letter contained a range of details relating not just to easily obtained facts and conditions existing at the time of the tip, but to future actions of third parties ordinarily not easily predicted. The letterwriter’s accurate information as to the travel plans of each of the Gateses was of a character likely obtained only from the Gateses themselves, or from someone familiar with their not entirely ordinary travel plans. If the informant had access to accurate information of this type a magistrate could properly conclude that it was not unlikely that he also had access to reliable information of the Gateses’ alleged illegal activities.14 Of *246course, the Gateses’ travel plans might have been learned from a talkative neighbor or travel agent; under the “two-pronged test” developed from Spinelli, the character of the details in the anonymous letter might well not permit a sufficiently clear inference regarding the letterwriter’s “basis of knowledge.” But, as discussed previously, supra, at 235, probable cause does not demand the certainty we associate with formal trials. It is enough that there was a fair probability that the writer of the anonymous letter had obtained his entire story either from the Gateses or someone they trusted. And corroboration of major portions of the letter’s predictions provides just this probability. It is apparent, therefore, that the judge issuing the warrant had a “substantial basis for . . . conclud[ing]” that probable cause to search the Gateses’ home and car existed. The judgment of the Supreme Court of Illinois therefore must be

Reversed.

Justice White,

concurring in the judgment.

In my view, the question regarding modification of the exclusionary rule framed in our order of November 29, 1982, 459 U. S. 1028 (1982), is properly before us and should be addressed. I continue to believe that the exclusionary rule is an inappropriate remedy where law enforcement officials act in the reasonable belief that a search and seizure was consistent with the Fourth Amendment — a position I set forth in Stone v. Powell, 428 U. S. 465, 537-539 (1976). In this case, it was fully reasonable for the Bloomingdale, Ill., police to believe that their search of respondents’ house and automobile comported with the Fourth Amendment as the search was conducted pursuant to a judicially issued warrant. The *247exclusion of probative evidence where the constable has not blundered not only sets the criminal free but also fails to serve any constitutional interest in securing compliance with the important requirements of the Fourth Amendment. On this basis, I concur in the Court’s judgment that the decision of the Illinois Supreme Court must be reversed.

h — 1

The Court declines to address the exclusionary rule question because the Illinois courts were not invited to modify the rule in the first instance. The Court’s refusal to face this important question cannot be ascribed to jurisdictional limitations. I fully agree that the statute which gives us jurisdiction in this cause, 28 U. S. C. § 1257(3), prevents us from deciding federal constitutional claims raised here for the first time on review of state-court decisions. Cardinale v. Louisiana, 394 U. S. 437, 438-439 (1969). But it is equally well established that “ ‘[n]o particular form of words or phrases is essential, but only that the claim of invalidity and the ground therefor be brought to the attention of the state court with fair precision and in due time.’” Street v. New York, 394 U. S. 576, 584 (1969) (quoting New York ex rel. Bryant v. Zimmerman, 278 U. S. 63, 67 (1928)). Notwithstanding the select and controversial instances in which the Court has reversed a state-court decision for “plain error,”1 we have consistently dismissed for want of jurisdiction where the federal claim asserted in this Court was not raised below. But this obviously is not such a case. As the Court points out, “[i]t is clear in this case that respondents expressly raised, at every level of the Illinois judicial system, the claim that the Fourth Amendment had been violated by the actions of the Illinois *248police and that the evidence seized by the officers should be excluded from their trial.” Ante, at 220. Until today, we have not required more.

We have never suggested that the jurisdictional stipulations of § 1257 require that all arguments on behalf of, let alone in opposition to, a federal claim be raised and decided below.2 See R. Stern & E. Gressman, Supreme Court Practice 230 (5th ed. 1978). Dewey v. Des Moines, 173 U. S. 193 (1899), distinguished the raising of constitutional claims and the making of arguments in support of or in opposition to those claims.

“If the question were only an enlargement of the one mentioned in the assignment of errors, or if it were so connected with it in substance as to form but another ground or reason for alleging the invalidity of the personal judgment, we should have no hesitation in holding the assignment sufficient to permit the question to be now raised and argued.

“Parties are not confined here to the same arguments which were advanced in the courts below upon a Federal question there discussed.” Id., at 197-198 (emphasis added).3

*249Under Dewey, which the Court hails as the “fullest treatment of the subject,” ante, at 219, the exclusionary rule issue is but another argument pertaining to the Fourth Amendment question squarely presented in the Illinois courts.

The presentation and decision of respondents’ Fourth Amendment claim fully embraces the argument that due to the nature of the alleged Fourth Amendment violation, the seized evidence should not be excluded. Our decisions concerning the scope of the exclusionary rule cannot be divorced from the Fourth Amendment; they rest on the relationship of Fourth Amendment interests to the objectives of the criminal justice system. See, e. g., United States v. Ceccolini, 435 U. S. 268 (1978); Stone v. Powell, 428 U. S. 465 (1976).4 Similarly, the issues surrounding a proposed good-faith modification are intricately and inseverably tied to the nature of the Fourth Amendment violation: the degree of probable cause, the presence of a warrant, and the clarity of previously announced Fourth Amendment principles all inform the *250good-faith issue. The Court’s own holding that the duty of a reviewing court is simply to ensure that the magistrate had a “substantial basis” for concluding that probable cause existed, ante, at 244-245, is itself but a variation on the good-faith theme. See Brief for Petitioner on Reargument 4-26.

As a jurisdictional requirement, I have no doubt that the exclusionary rule question is before us as an indivisible element of the claim that the Constitution requires exclusion of certain evidence seized in violation of the Fourth Amendment. As a prudential matter, I am unmoved by the Court’s lengthy discourse as to why it must avoid the question. First, the Court turns on its head the axiom that “‘due regard for the appropriate relationship of this Court to state courts,’McGoldrick v. Compagnie Generale Transatlantique, 309 U. S., at 434-435, demands that those courts be given an opportunity to consider the constitutionality of the actions of state officials,” ante, at 221. This statement, written to explain why a state statute should not be struck down on federal grounds not raised in the state courts,5 hardly applies when the question is whether a rule of federal law articulated by this Court should now be narrowed to reduce the scope of federal intrusion into the State’s administration of criminal justice. Insofar as modifications of the federal exclusionary *251rule are concerned, the Illinois courts are bound by this Court’s pronouncements. Cf. Oregon v. Hass, 420 U. S. 714, 719 (1975). I see little point in requiring a litigant to request a state court to overrule or modify one of this Court’s precedents. Far from encouraging the stability of our precedents, the Court’s proposed practice could well undercut stare decisis. Either the presentation of such issues to the lower courts will be a completely futile gesture or the lower courts are now invited to depart from this Court’s decisions whenever they conclude such a modification is in order.6

The Court correctly notes that Illinois may choose to pursue a different course with respect to the state exclusionary rule. If this Court were to formulate a “good-faith” exception to the federal exclusionary rule, the Illinois Supreme Court would be free to consider on remand whether the state exclusionary rule should be modified accordingly. The possibility that it might have relied upon the state exclusionary rule had the “good-faith” question been posed does not constitute independent and adequate state grounds. “The possibility that the state court might have reached the same conclusion if it had decided the question purely as a matter of state law does not create an adequate and independent state ground that relieves this Court of the necessity of considering the federal question.” United Air Lines, Inc. v. Mahin, 410 U. S. 623, 630-631 (1973); Beecher v. Alabama, 389 U. S. 35, 37, n. 3 (1967); C. Wright, The Law of Federal Courts § 107, pp. 747-748 (4th ed. 1983). Nor does having the state court first decide whether the federal exclusionary rule should be modified — and presentation of the federal question does not insure that the equivalent state-law issue will be *252raised or decided7 — avoid the unnecessary decision of a federal question. The Court still must reach a federal question to decide the instant case. Thus, in today’s opinion, the Court eschews modification of the exclusionary rule in favor of interring the test established by Aguilar v. Texas, 378 U. S. 108 (1964), and Spinelli v. United States, 393 U. S. 410 (1969). Nor is the exclusionary rule question avoided — it is simply deferred until “another day.”

It also appears that the Court, in disposing of the case, does not strictly follow its own prudential advice. The Illinois Supreme Court found not only a violation of the Fourth Amendment but also of Article I, § 6, of the Illinois Constitution, which also provides assurance against unreasonable searches and seizures. Taking the Court’s new prudential standards on their own terms, the Illinois courts should be given the opportunity to consider in the first instance whether a “totality of the circumstances” test should replace the more precise rules of Aguilar and Spinelli. The Illinois Supreme Court may decide to retain the established test for purposes of the State Constitution just as easily as it could decide to retain an unmodified exclusionary rule.8

Finally, the Court correctly notes that a fully developed record is helpful if not indispensable for the decision of many issues. I too resist the decision of a constitutional question *253when such guidance is necessary, but the question of whether the exclusionary rule should be modified is an issue of law which obviously goes far beyond and depends little on the subjective good faith of the police officers that searched the Gateses’ property. Moreover, the case comes here with a fully developed record as to the actions of the Bloomingdale, Ill., police. If further factual development of whether the officers in this case acted in good faith were important, that issue should logically be considered on remand, following this Court’s statement of the proper legal standards.9

The Court’s straining to avoid coming to grips with the exclusionary rule issue today may be hard for the country to understand — particularly given earlier statements by some Members of the Court.10 The question has been fully briefed and argued by the parties and amici curiae, including the United States.11 The issue is central to the enforcement of law and the administration of justice throughout the Nation. The Court of Appeals for the second largest Federal Circuit *254has already adopted such an exception, United States v. Williams, 622 F. 2d 880 (CA5 1980) (en banc), cert. denied, 449 U. S. 1127 (1981), and the new Eleventh Circuit is presumably bound by its decision. Several Members of this Court have for some time expressed the need to consider modifying the exclusionary rule, ante, at 224, and Congress as well has been active in exploring the question. See The Exclusionary Rule Bills, Hearings on S. 101, S. 751, and S. 1995 before the Subcommittee on Criminal Law of the Senate Committee on the Judiciary, 97th Cong., 1st and 2d Sess. (1981-1982). At least one State has already enacted a good-faith exception. Colo. Rev. Stat. § 16-3-308 (Supp. 1982). Of course, if there is a jurisdictional barrier to deciding the issue, none of these considerations are relevant. But if no such procedural obstacle exists, I see it as our responsibility to end the uncertainty and decide whether the rule will be modified. The question of whether probable cause existed for the issuance of a warrant and whether the evidence seized must be excluded in this case should follow our reconsideration of the framework by which such issues, as they arise from the Fourth Amendment, are to be handled.

H

>

The exclusionary rule is a remedy adopted by this Court to effectuate the Fourth Amendment right of citizens “to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures . . . Although early opinions suggested that the Constitution required exclusion of all illegally obtained evidence, the exclusionary rule “has never been interpreted to proscribe the introduction of illegally seized evidence in all proceedings or against all persons.” Stone v. Powell, 428 U. S., at 486. Because of the inherent trustworthiness of seized tangible evidence and the resulting social costs from its loss through suppression, appli*255cation of the exclusionary rule has been carefully “restricted to those areas where its remedial objectives are thought most efficaciously served.” United States v. Calandra, 414 U. S. 338, 348 (1974). Even at criminal trials the exclusionary rule has not been applied indiscriminately to ban all illegally obtained evidence without regard to the costs and benefits of doing so. Infra, at 256-257. These developments, born of years of experience with the exclusionary rule in operation, forcefully suggest that the exclusionary rule be more generally modified to permit the introduction of evidence obtained in the reasonable good-faith belief that a search or seizure was in accord with the Fourth Amendment.

This evolvement in the understanding of the proper scope of the exclusionary rule embraces several lines of cases. First, standing to invoke the exclusionary rule has been limited to situations where the government seeks to use such evidence against the victim of the unlawful search. Brown v. United States, 411 U. S. 223 (1973); Alderman v. United States, 394 U. S. 165 (1969); Wong Sun v. United States, 371 U. S. 471, 491-492 (1963); Rakas v. Illinois, 439 U. S. 128 (1978).

Second, the rule has not been applied in proceedings other than the trial itself. In United States v. Calandra, supra, the Court refused to extend the rule to grand jury proceedings. “Any incremental deterrent effect which might be achieved by extending the rule to grand jury proceedings is uncertain at best. . . . We therefore decline to embrace a view that would achieve a speculative and undoubtedly minimal advance in the deterrence of police misconduct at the expense of substantially impeding the role of the grand jury.” 414 U. S., at 351-352. Similarly, in United States v. Janis, 428 U. S. 433 (1976), the exclusionary rule was not extended to forbid the use in federal civil proceedings of evidence illegally seized by state officials, since the likelihood of deterring unlawful police conduct was not sufficient to outweigh the social costs imposed by the exclusion.

*256Third, even at a criminal trial, the same analysis has led us to conclude that the costs of excluding probative evidence outweighed the deterrence benefits in several circumstances. We have refused to prohibit the use of illegally seized evidence for the purpose of impeaching a defendant who testifies in his own behalf. United States v. Havens, 446 U. S. 620 (1980); Walder v. United States, 347 U. S. 62 (1954). We have also declined to adopt a “per se or ‘but for’ rule” that would make inadmissible any evidence which comes to light through a chain of causation that began with an illegal arrest. Brown v. Illinois, 422 U. S. 590, 603 (1975). And we have held that testimony of a live witness may be admitted, notwithstanding that the testimony was derived from a con-cededly unconstitutional search. United States v. Ceccolini, 435 U. S. 268 (1978). Nor is exclusion required when law enforcement agents act in good-faith reliance upon a statute or ordinance that is subsequently held to be unconstitutional. United States v. Peltier, 422 U. S. 531 (1975); Michigan v. DeFillippo, 443 U. S. 31 (1979).12 Cf. United States v. Caceres, 440 U. S. 741, 754-757 (1979) (exclusion not *257required of evidence tainted by violation of an executive department’s rules concerning electronic eavesdropping).

A similar balancing approach is employed in our decisions limiting the scope of the exclusionary remedy for Fifth Amendment violations, Oregon v. Hass, 420 U. S. 714 (1975); Harris v. New York, 401 U. S. 222 (1971); Michigan v. Tucker, 417 U. S. 433 (1974), and our cases considering whether Fourth Amendment decisions should be applied retroactively, United States v. Peltier, supra, at 538-539; Williams v. United States, 401 U. S. 646, 654-655 (1971) (plurality opinion); Desist v. United States, 394 U. S. 244, 249-250 (1969); Linkletter v. Walker, 381 U. S. 618, 636-639 (1965). But see United States v. Johnson, 457 U. S. 537 (1982).

These cases reflect that the exclusion of evidence is not a personal constitutional right but a remedy, which, like all remedies, must be sensitive to the costs and benefits of its imposition. The trend and direction of our exclusionary rule decisions indicate not a lesser concern with safeguarding the Fourth Amendment but a fuller appreciation of the high costs incurred when probative, reliable evidence is barred because of investigative error. The primary cost, of course, is that the exclusionary rule interferes with the truthseeking function of a criminal trial by barring relevant and trustworthy evidence.13 We will never know how many guilty defendants go free as a result of the rule’s operation. But any rule of evidence that denies the jury access to clearly probative and reliable evidence must bear a heavy burden of justification, *258and must be carefully limited to the circumstances in which it will pay its way by deterring official lawlessness. I do not presume that modification of the exclusionary rule will, by itself, significantly reduce the crime rate — but that is no excuse for indiscriminate application of the rule.

The suppression doctrine entails other costs as well. It would be surprising if the suppression of evidence garnered in good faith, but by means later found to violate the Fourth Amendment, did not deter legitimate as well as unlawful police activities. To the extent the rule operates to discourage police from reasonable and proper investigative actions, it hinders the solution and even the prevention of crime. A tremendous burden is also placed on the state and federal judicial systems. One study reveals that one-third of federal defendants going to trial file Fourth Amendment suppression motions, and 70% to 90% of these involve formal hearings. General Accounting Office, Comptroller General of the United States, Impact of the Exclusionary Rule on Federal Criminal Prosecutions 10 (1979).

The rule also exacts a heavy price in undermining public confidence in the reasonableness of the standards that govern the criminal justice system. “[Although the [exclusionary] rule is thought to deter unlawful police activity in part through the nurturing of respect for Fourth Amendment values, if applied indiscriminately it may well have the opposite effect of generating disrespect for the law and the administration of justice.” Stone v. Powell, 428 U. S., at 490-491. As Justice Powell observed in Stone v. Powell, supra, at 490: “The disparity in particular cases between the error committed by the police officer and the windfall afforded a guilty defendant by application of the rule is contrary to the idea of proportionality that is essential to the concept of justice.”

For these reasons, “application of the [exclusionary] rule has been restricted to those areas where its remedial objectives are thought most efficaciously served.” United States *259v. Calandra, 414 U. S., at 348.14 The reasoning of our recent cases strongly suggests that there is insufficient justification to suppress evidence at a criminal trial which was seized in the reasonable belief that the Fourth Amendment was not violated. The deterrent effect of the exclusionary rule has never been established by empirical evidence, de*260spite repeated attempts. United States v. Janis, 428 U. S., at 449-453; Irvine v. California, 347 U. S. 128, 136 (1954). But accepting that the rule deters some police misconduct, it is apparent as a matter of logic that there is little if any deterrence when the rule is invoked to suppress evidence obtained by a police officer acting in the reasonable belief that his conduct did not violate the Fourth Amendment. As we initially observed in Michigan v. Tucker, 417 U. S., at 447, and reiterated in United States v. Peltier, 422 U. S., at 539:

“ ‘The deterrent purpose of the exclusionary rule necessarily assumes that the police have engaged in willful, or at the very least negligent, conduct which has deprived the defendant of some right. By refusing to admit evidence gained as a result of such conduct, the courts hope to instill in those particular investigating officers, or in their future counterparts, a greater degree of care toward the rights of an accused. Where the official action was pursued in complete good faith, however, the deterrence rationale loses much of its force.’”

The Court in Peltier continued, id., at 542:

“If the purpose of the exclusionary rule is to deter unlawful police conduct then evidence obtained from a search should be suppressed only if it can be said that the law enforcement officer had knowledge, or may properly be charged with knowledge, that the search was unconstitutional under the Fourth Amendment.”

See also United States v. Janis, supra, at 459, n. 35 (“[T]he officers here were clearly acting in good faith ... a factor that the Court has recognized reduces significantly the potential deterrent effect of exclusion”). The deterrent value of the exclusionary sanction is most effective when officers engage in searches and seizures under circumstances “so lacking in indicia of probable cause as to render official belief in its existence entirely unreasonable.” Brown v. Illinois, 422 U. S., at 610-611 (Powell, J., concurring in part). On the *261other hand, when officers perform their tasks in the good-faith belief that their action comported with constitutional requirements, the deterrent function of the exclusionary rule is so minimal, if not nonexistent, that the balance clearly favors the rule’s modification.15

*262B

There are several types of Fourth Amendment violations that may be said to fall under the rubric of “good faith.” “[TJhere will be those occasions where the trial or appellate court will disagree on the issue of probable cause, no matter how reasonable the grounds for arrest appeared to the officer and though reasonable men could easily differ on the question. It also happens that after the events at issue have occurred, the law may change, dramatically or ever so slightly, but in any event sufficiently to require the trial judge to hold that there was not probable cause to make the arrest and to seize the evidence offered by the prosecution. ...” Stone v. Powell, 428 U. S., at 539-540 (White, J., dissenting). The argument for a good-faith exception is strongest, however, when law enforcement officers have reasonably relied on a judicially issued search warrant.

This Court has never set forth a rationale for applying the exclusionary rule to suppress evidence obtained pursuant to a search warrant; it has simply done so without considering whether Fourth Amendment interests will be advanced. It is my view that they generally will not be. When officers have dutifully obtained a search warrant from a judge or magistrate, and execute the warrant as directed by its terms, .exclusion of the evidence thus obtained cannot be expected to deter future reliance on such warrants. The warrant is prima facie proof that the officers acted reasonably in conducting the search or seizure; “[o]nce the warrant issues, there is literally nothing more that the policeman can do in seeking to comply with the law.” Stone v. Powell, supra, at 498 (Burger, C. J., concurring).16 As Justice Stevens *263put it in writing for the Court in United States v. Ross, 456 U. S. 798, 823, n. 32 (1982): “[A] warrant issued by a magistrate normally suffices to establish” that a law enforcement officer has “acted in good faith in conducting the search.” Nevertheless, the warrant may be invalidated because of a technical defect or because, as in this case, the judge issued a warrant on information later determined to fall short of probable cause. Excluding evidence for these reasons can have no possible deterrent effect on future police conduct, unless it is to make officers less willing to do their duty. Indeed, applying the exclusionary rule to warrant searches may well reduce incentives for police to utilize the preferred warrant procedure when a warrantless search may be permissible under one of the established exceptions to the warrant requirement. See ante, at 236; Brown v. Illinois, 422 U. S., at 611, and n. 3 (Powell, J., concurring in part); P. Johnson, New Approaches to Enforcing the Fourth Amendment 11 (unpublished paper, 1978). See also United States v. United States District Court, 407 U. S. 297, 316-317 (1972); United States v. Ventresca, 380 U. S. 102, 106-107 (1965).

Opponents of the proposed “reasonable belief” exception suggest that such a modification would allow magistrates and judges to flout the probable-cause requirements in issuing warrants. This is a novel concept: the exclusionary rule was adopted to deter unlawful searches by police, not to punish the errors of magistrates and judges. Magistrates must be neutral and detached from law enforcement operations and I would not presume that a modification of the exclusionary rule will lead magistrates to abdicate their responsibility to apply the law.17 In any event, I would apply the exclusion*264ary rule when it is plainly evident that a magistrate or judge had no business issuing a warrant. See, e. g., Aguilar v. Texas, 378 U. S. 108 (1964); Nathanson v. United States, 290 U. S. 41 (1933). Similarly, the good-faith exception would not apply if the material presented to the magistrate or judge is false or misleading, Franks v. Delaware, 438 U. S. 154 (1978), or so clearly lacking in probable cause that no well-trained officer could reasonably have thought that a warrant should issue.

Another objection is that a reasonable-belief exception will encompass all searches and seizures on the frontier of the Fourth Amendment and that such cases will escape review on the question of whether the officer’s action was permissible, denying needed guidance from the courts and freezing Fourth Amendment law in its present state. These fears are unjustified. The premise of the argument is that a court must first decide the reasonable-belief issue before turning to the question of whether a Fourth Amendment violation has occurred. I see no need for such an inflexible practice. When a Fourth Amendment case presents a novel question of law whose resolution is necessary to guide future action by law enforcement officers and magistrates, there is sufficient reason for the Court to decide the violation issue before turning to the good-faith question. Indeed, it may be difficult to *265determine whether the officers acted reasonably until the Fourth Amendment issue is resolved.18 In other circumstances, however, a suppression motion poses no Fourth Amendment question of broad import — the issue is simply whether the facts in a given case amounted to probable cause — in these cases, it would be prudent for a reviewing court to immediately turn to the question of whether the officers acted in good faith. Upon finding that they had, there would generally be no need to consider the probable-cause question. I doubt that our Fourth Amendment jurisprudence would suffer thereby. It is not entirely clear to me that the law in this area has benefited from the constant pressure of fully litigated suppression motions. The result usually has been that initially bright-line rules have disappeared in a sea of ever-finer distinctions. Moreover, there is much to be said for having Fourth Amendment jurispru*266dence evolve in part, albeit perhaps at a slower pace, in other settings.19

Finally, it is contended that a good-faith exception will be difficult to apply in practice. This concern appears grounded in the assumption that courts would inquire into the subjective belief of the law enforcement officers involved. I would eschew such investigations. “[Sjending state and federal courts on an expedition into the minds of police officers would produce a grave and fruitless misallocation of judicial resources.” Massachusetts v. Painten, 389 U. S. 560, 565 (1968) (White, J., dissenting). Moreover, “[sjubjective intent alone . . . does not make otherwise lawful conduct illegal or unconstitutional.” Scott v. United States, 436 U. S. 128, 136 (1978). Just last Term, we modified the qualified immunity public officials enjoy in suits seeking damages against federal officials for alleged deprivations of constitutional rights, eliminating the subjective component of the standard. See Harlow v. Fitzgerald, 457 U. S. 800 (1982). Although *267searches pursuant to a warrant will rarely require any deep inquiry into reasonableness, I would measure the reasonableness of a particular search or seizure only by objective standards. Even for warrantless searches, the requirement should be no more difficult to apply than the closely related good-faith test which governs civil suits under 42 U. S. C. § 1983. In addition, the burden will likely be offset by the reduction in the number of cases which will require elongated considerations of the probable-cause question, and will be greatly outweighed by the advantages in limiting the bite of the exclusionary rule to the field in which it is most likely to have its intended effects.

hH h — I HH

Since a majority of the Court deems it inappropriate to address the good-faith issue, I briefly address the question that the Court does reach — whether the warrant authorizing the search and seizure of respondents’ car and home was constitutionally valid. Abandoning the “two-pronged test” of Aguilar v. Texas, 378 U. S. 108 (1964), and Spinelli v. United States, 393 U. S. 410 (1969), the Court upholds the validity of the warrant under a new “totality of the circumstances” approach. Although I agree that the warrant should be upheld, I reach this conclusion in accordance with the Aguilar-Spinelli framework.

A

For present purposes, the Aguilar-Spinelli rules can be summed up as follows. First, an affidavit based on an informant’s tip, standing alone, cannot provide probable cause for issuance of a warrant unless the tip includes information that apprises the magistrate of the informant’s basis for concluding that the contraband is where he claims it is (the “basis of knowledge” prong), and the affiant informs the magistrate of his basis for believing that the informant is credible (the “veracity” prong). Aguilar, supra, at 114; *268Spinelli, supra, at 412-413,416.20 Second, if a tip fails under either or both of the two prongs, probable cause may yet be established by independent police investigatory work that corroborates the tip to such an extent that it supports “both the inference that the informer was generally trustworthy and that he made his charge ... on the basis of information obtained in a reliable way.” Spinelli, supra, at 417. In instances where the officers rely on corroboration, the ultimate question is whether the corroborated tip “is as trustworthy as a tip which would pass Aguilar's tests without independent corroboration.” 393 U. S., at 415.

In the present case, it is undisputed that the anonymous tip, by itself, did not furnish probable cause. The question is whether those portions of the affidavit describing the results of the police investigation of the respondents, when considered in light of the tip, “would permit the suspicions engendered by the informant’s report to ripen into a judgment that a crime was probably being committed.” Spinelli, supra, at 418. The Illinois Supreme Court concluded that the corroboration was insufficient to permit such a ripening. 85 Ill. 2d 376, 387, 423 N. E. 2d 887, 892 (1981). The court reasoned as follows:

“[T]he nature of the corroborating evidence in this case would satisfy neither the ‘basis of knowledge’ nor the *269‘veracity’ prong of Aguilar. Looking to the affidavit submitted as support for Detective Mader’s request that a search warrant issue, we note that the corroborative evidence here was only of clearly innocent activity. Mader’s independent investigation revealed only that Lance and Sue Gates lived on Greenway Drive; that Lance Gates booked passage on a flight to Florida; that upon arriving he entered a room registered to his wife; and that he and his wife left the hotel together by car. The corroboration of innocent activity is insufficient to support a finding of probable cause.” Id., at 390, 423 N. E. 2d, at 893.

In my view, the lower court’s characterization of the Gateses’ activity here as totally “innocent” is dubious. In fact, the behavior was quite suspicious. I agree with the Court, ante, at 243, that Lance Gates’ flight to West Palm Beach, an area known to be a source of narcotics, the brief overnight stay in a motel, and apparent immediate return north, suggest a pattern that trained law enforcement officers have recognized as indicative of illicit drug-dealing activity.21

Even, however, had the corroboration related only to completely innocuous activities, this fact alone would not preclude the issuance of a valid warrant. The critical issue is not whether the activities observed by the police are innocent or suspicious. Instead, the proper focus should be on whether the actions of the suspects, whatever their nature, give rise to an inference that the informant is credible and that he obtained his information in a reliable manner.

Thus, in Draper v. United States, 358 U. S. 307 (1959), an informant stated on September 7 that Draper would be carrying narcotics when he arrived by train in Denver on the morning of September 8 or September 9. The informant also provided the police with a detailed physical description *270of the clothes Draper would be wearing when he alighted from the train. The police observed Draper leaving a train on the morning of September 9, and he was wearing the precise clothing described by the informant. The Court held that the police had probable cause to arrest Draper at this point, even though the police had seen nothing more than the totally innocent act of a man getting off a train carrying a briefcase. As we later explained in Spinelli, the important point was that the corroboration showed both that the informant was credible, i. e., that he “had not been fabricating his report out of whole cloth,” Spinelli, 393 U. S., at 417, and that he had an adequate basis of knowledge for his allegations, “since the report was of the sort which in common experience may be recognized as having been obtained in a reliable way.” Id., at 417-418. The fact that the informant was able to predict, two days in advance, the exact clothing Draper would be wearing dispelled the possibility that his tip was just based on rumor or “an offhand remark heard at a neighborhood bar.” Id., at 417. Probably Draper had planned in advance to wear these specific clothes so that an accomplice could identify him. A clear inference could therefore be drawn that the informant was either involved in the criminal scheme himself or that he otherwise had access to rehable, inside information.22

*271As in Draper, the police investigation in the present case satisfactorily demonstrated that the informant’s tip was as trustworthy as one that would alone satisfy the Aguilar tests. The tip predicted that Sue Gates would drive to Florida, that Lance Gates would fly there a few days after May 3, and that Lance would then drive the car back. After the police corroborated these facts,23 the judge could reasonably have inferred, as he apparently did, that the informant, who had specific knowledge of these unusual travel plans, did not make up his story and that he obtained his information in a reliable way. It is theoretically possible, as respondents insist, that the tip could have been supplied by a “vindictive travel agent” and that the Gateses’ activities, although unusual, might not have been unlawful.24 But Aguilar and Spinelli, like our other cases, do not require that certain guilt be established before a warrant may properly be issued. “[OJnly the probability, and not a prima facie show*272ing, of criminal activity is the standard of probable cause.” Spinelli, supra, at 419 (citing Beck v. Ohio, 379 U. S. 89, 96 (1964)). I therefore conclude that the judgment of the Illinois Supreme Court invalidating the warrant must be reversed.

B

The Court agrees that the warrant was valid, but, in the process of reaching this conclusion, it overrules the Aguilar-Spinelli tests and replaces them with a “totality of the circumstances” standard. As shown above, it is not at all necessary to overrule Aguilar-Spinelli in order to reverse the judgment below. Therefore, because I am inclined to believe that, when applied properly, the Aguilar-Spinelli rules play an appropriate role in probable-cause determinations, and because the Court’s holding may foretell an evisceration of the probable-cause standard, I do not join the Court’s holding.

The Court reasons, ante, at 233, that the “veracity” and “basis of knowledge” tests are not independent, and that a deficiency as to one can be compensated for by a strong showing as to the other. Thus, a finding of probable cause may be based on a tip from an informant “known for the unusual reliability of his predictions” or from “an unquestionably honest citizen,” even if the report fails thoroughly to set forth the basis upon which the information was obtained. Ibid. If this is so, then it must follow a fortiori that “the affidavit of an officer, known by the magistrate to be honest and experienced, stating that [contraband] is located in a certain building” must be acceptable. Spinelli, 393 U. S., at 424 (White, J., concurring). It would be “quixotic” if a similar statement from an honest informant, but not one from an honest officer, could furnish probable cause. Ibid. But we have repeatedly held that the unsupported assertion or belief of an officer does not satisfy the probable-cause requirement. See, e. g., Whiteley v. Warden, 401 U. S. 560, 564-565 *273(1971); Jones v. United States, 362 U. S. 257, 269 (1960); Nathanson v. United States, 290 U. S. 41 (1933).25 Thus, this portion of today’s holding can be read as implicitly rejecting the teachings of these prior holdings.

The Court may not intend so drastic a result. Indeed, the Court expressly reaffirms, ante, at 239, the validity of cases such as Nathanson that have held that, no matter how reliable the affiant-officer may be, a warrant should not be issued unless the affidavit discloses supporting facts and circumstances. The Court limits these cases to situations involving affidavits containing only “bare conclusions” and holds that, if an affidavit contains anything more, it should be left to the issuing magistrate to decide, based solely on “practicality]” and “common sense,” whether there is a fair probability that contraband will be found in a particular place. Ante, at 238-239.

Thus, as I read the majority opinion, it appears that the question whether the probable-cause standard is to be diluted is left to the common-sense judgments of issuing magistrates. I am reluctant to approve any standard that does not expressly require, as a prerequisite to issuance of a warrant, some showing of facts from which an inference may be drawn that the informant is credible and that his information was obtained in a reliable way. The Court is correctly concerned with the fact that some lower courts have been applying Aguilar-Spinelli in an unduly rigid manner.26 I believe, however, that with clarification of the rule of corroborating *274information, the lower courts are fully able to properly interpret Aguilar-Spinelli and avoid such unduly rigid applications. I may be wrong; it ultimately may prove to be the case that the only profitable instruction we can provide to magistrates is to rely on common sense. But the question whether a particular anonymous tip provides the basis for issuance of a warrant will often be a difficult one, and I would at least attempt to provide more precise guidance by clarifying Aguilar-Spinelli and the relationship of those cases with Draper before totally abdicating our responsibility in this area. Hence, I do not join the Court’s opinion rejecting the Aguilar-Spinelli rules.

Justice Brennan,

with whom Justice Marshall joins,

dissenting.

Although I join Justice Stevens’ dissenting opinion and agree with him that the warrant is invalid even under the Court’s newly announced “totality of the circumstances” test, see post, at 294-295, and n. 8, I write separately to dissent from the Court’s unjustified and ill-advised rejection of the two-prong test for evaluating the validity of a warrant based on hearsay announced in Aguilar v. Texas, 378 U. S. 108 (1964), and refined in Spinelli v. United States, 393 U. S. 410 (1969).

I

The Court’s current Fourth Amendment jurisprudence, as reflected by today’s unfortunate decision, patently disregards Justice Jackson’s admonition in Brinegar v. United States, 338 U. S. 160 (1949):

“[Fourth Amendment rights] are not mere second-class rights but belong in the catalog of indispensable freedoms. Among deprivations of rights, none is so effective in cowing a population, crushing the spirit of the individual and putting terror in every heart. *275Uncontrolled search and seizure is one of the first and most effective weapons in the arsenal of every arbitrary government. . . .

“But the right to be secure against searches and seizures is one of the most difficult to protect. Since the officers are themselves the chief invaders, there is no enforcement outside of court.” Id., at 180-181 (dissenting opinion).

In recognition of the judiciary’s role as the only effective guardian of Fourth Amendment rights, this Court has developed over the last half century a set of coherent rules governing a magistrate’s consideration of a warrant application and the showings that are necessary to support a finding of probable cause. We start with the proposition that a neutral and detached magistrate, and not the police, should determine whether there is probable cause to support the issuance of a warrant. In Johnson v. United States, 333 U. S. 10 (1948), the Court stated:

“The point of the Fourth Amendment, which often is not grasped by zealous officers, is not that it denies law enforcement the support of the usual inferences which reasonable men draw from evidence. Its protection consists in requiring that those inferences be drawn by a neutral and detached magistrate instead of being judged by the officer engaged in the often competitive enterprise of ferreting out crime. . . . When the right of privacy must reasonably yield to the right of search is, as a rule, to be decided by a judicial officer, not by a policeman or government enforcement agent.” Id., at 13-14 (footnote omitted).

See also Whiteley v. Warden, 401 U. S. 560, 564 (1971); Spinelli v. United States, supra, at 415; United States v. Ventresca, 380 U. S. 102, 109 (1965); Aguilar v. Texas, supra, at 111; Jones v. United States, 362 U. S. 257, 270-271 *276(1960); Giordenello v. United States, 357 U. S. 480, 486 (1958); United States v. Lefkowitz, 285 U. S. 452, 464 (1932).

In order to emphasize the magistrate’s role as an independent arbiter of probable cause and to insure that searches or seizures are not effected on less than probable cause, the Court has insisted that police officers provide magistrates with the underlying facts and circumstances that support the officers’ conclusions. In Nathanson v. United States, 290 U. S. 41 (1933), the Court held invalid a search warrant that was based on a customs agent’s “mere affirmation of suspicion and belief without any statement of adequate supporting facts.” Id., at 46. The Court stated: “Under the Fourth Amendment, an officer may not properly issue a warrant to search a private dwelling unless he can find probable cause therefor from facts or circumstances presented to him under oath or affirmation. Mere affirmance of belief or suspicion is not enough.” Id., at 47.

In Giordenello v. United States, supra, the Court reviewed an arrest warrant issued under the Federal Rules of Criminal Procedure based on a complaint sworn to by a Federal Bureau of Narcotics agent. Id., at 481.1 Based on the agent’s testimony at the suppression hearing, the Court noted that “until the warrant was issued . . . [the agent’s] suspicions of petitioner’s guilt derived entirely from information given him by law enforcement officers and other persons in Houston, none of whom either appeared before the Commissioner or submitted affidavits.” Id., at 485. The Court found it unnecessary to decide whether a warrant could be based solely on hearsay information, for the complaint was “defective in not providing a sufficient basis upon which a *277finding of probable cause could be made.” Ibid. In particular, the complaint contained no affirmative allegation that the agent spoke with personal knowledge nor did it indicate any sources for the agent’s conclusion. Id., at 486. The Court expressly rejected the argument that these deficiencies could be cured by “the Commissioner’s reliance upon a presumption that the complaint was made on the personal knowledge of the complaining officer.” Ibid.

As noted, the Court did not decide the hearsay question lurking in Giordenello. The use of hearsay to support the issuance of a warrant presents special problems because informants, unlike police officers, are not regarded as presumptively reliable or honest. Moreover, the basis for an informant’s conclusions is not always clear from an affidavit that merely reports those conclusions. If the conclusory allegations of a police officer are insufficient to support a finding of probable cause, surely the conclusory allegations of an informant should a fortiori be insufficient.

In Jones v. United States, supra, the Court considered “whether an affidavit which sets out personal observations relating to the existence of cause to search is to be deemed insufficient by virtue of the fact that it sets out not the affi-ant’s observations but those of another.” Id., at 269. The Court held that hearsay information can support the issuance of a warrant “so long as a substantial basis for crediting the hearsay is presented.” Ibid. The Court found that there was a substantial basis for crediting the hearsay involved in Jones. The informant’s report was based on the informant’s personal knowledge, and the informant previously had provided accurate information. Moreover, the informant’s story was corroborated by other sources. Finally, the defendant was known to the police to be a narcotics user. Id., at 271.

Aguilar v. Texas, 378 U. S. 108 (1964), merely made explicit what was implicit in Jones. In considering a search warrant based on hearsay, the Court reviewed Nathanson *278and Giordenello and noted the requirement established by those cases that an officer provide the magistrate with the underlying facts or circumstances that support the officer’s conclusion that there is probable cause to justify the issuance of a warrant. The Court stated:

“The vice in the present affidavit is at least as great as in Nathanson and Giordenello. Here, the ‘mere conclusion’ that petitioner possessed narcotics was not even that of the affiant himself; it was that of an unidentified informant. The affidavit here not only ‘contains no affirmative allegation that the affiant spoke with personal knowledge of the matters contained therein,’ it does not even contain an ‘affirmative allegation’ that the affiant’s unidentified source ‘spoke with personal knowledge.’ For all that appears, the source here merely suspected, believed or concluded that there were narcotics in petitioner’s possession. The magistrate here certainly could not ‘judge for himself the persuasiveness of the facts relied on ... to show probable cause.’ He necessarily accepted ‘without question’ the informant’s ‘suspicion,’ ‘belief’ or ‘mere conclusion.’” 378 U. S., at 113-114 (footnote omitted).2

While recognizing that a warrant may be based on hearsay, the Court established the following standard:

“[T]he magistrate must be informed of some of the underlying circumstances from which the informant con-*279eluded that the narcotics were where he claimed they were, and some of the underlying circumstances from which the officer concluded that the informant, whose identity need not be disclosed . . . was ‘credible’ or his information ‘reliable.’ Otherwise, ‘the inferences from the facts which lead to the complaint’ will be drawn not ‘by a neutral and detached magistrate,’ as the Constitution requires, but instead, by a police officer ‘engaged in the often competitive enterprise of ferreting out crime’ ... or, as in this case, by an unidentified informant.” Id., at 114-115 (footnote omitted).

The Aguilar standard was refined in Spinelli v. United States, 393 U. S. 410 (1969). In Spinelli, the Court reviewed a search warrant based on an affidavit that was “more ample,” id., at 413, than the one in Aguilar. The affidavit in Spinelli contained not only a tip from an informant, but also a report of an independent police investigation that allegedly corroborated the informant’s tip. 393 U. S., at 413. Under these circumstances, the Court stated that it was “required to delineate the manner in which Aguilar’s two-pronged test should be applied . . . .” Ibid.

The Court held that the Aguilar test should be applied to the tip, and approved two additional ways of satisfying that test. First, the Court suggested that if the tip contained sufficient detail describing the accused’s criminal activity it might satisfy Aguilar’s basis of knowledge prong. 393 U. S., at 416. Such detail might assure the magistrate that he is “relying on something more substantial than a casual rumor circulating in the underworld or an accusation based merely on an individual’s general reputation.” Ibid. Although the tip in the case before it did not meet this standard, “[t]he detail provided by the informant in Draper v. United States, 358 U. S. 307 (1959), provide[d] a suitable benchmark,” ibid., because “[a] magistrate, when confronted with such detail, could reasonably infer that the informant *280had gained his information in a reliable way.” Id., at 417 (footnote omitted).3

Second, the Court stated that police corroboration of the details of a tip could provide a basis for satisfying Aguilar. *281393 U. S., at 417. The Court’s opinion is not a model of clarity on this issue since it appears to suggest that corroboration can satisfy both the basis of knowledge and veracity prongs of Aguilar. 393 U. S., at 417-418.4 Justice White’s concurring opinion, however, points the way to a proper reading of the Court’s opinion. After reviewing the Court’s decision in Draper v. United States, 358 U. S. 307 (1959), Justice White concluded that “[t]he thrust of Draper is not that the verified facts have independent significance with respect to proof of [another unverified fact].” 393 U. S., at 427. In his view, “[t]he argument instead relates to the reliability of the source: because an informant is right about some things, he is more probably right about other facts, usually the critical, unverified facts.” Ibid. Justice White then pointed out that prior cases had rejected “the notion that the past *282reliability of an officer is sufficient reason for believing his current assertions.” Ibid. Justice White went on to state:

“Nor would it suffice, I suppose, if a reliable informant states there is gambling equipment in Apartment 607 and then proceeds to describe in detail Apartment 201, a description which is verified before applying for the warrant. He was right about 201, but that hardly makes him more believable about the equipment in 607. But what if he states that there are narcotics locked in a safe in Apartment 300, which is described in detail, and the apartment manager verifies everything but the contents of the safe? I doubt that the report about the narcotics is made appreciably more believable by the verification. The informant could still have gotten his information concerning the safe from others about whom nothing is known or could have inferred the presence of narcotics from circumstances which a magistrate would find unacceptable.” Ibid.

I find this reasoning persuasive. Properly understood, therefore, Spinelli stands for the proposition that corroboration of certain details in a tip may be sufficient to satisfy the veracity, but not the basis of knowledge, prong of Aguilar. As noted, Spinelli also suggests that in some limited circumstances considerable detail in an informant’s tip may be adequate to satisfy the basis of knowledge prong of Aguilar.5

*283Although the rules drawn from the cases discussed above are cast in procedural terms, they advance an important underlying substantive value: Findings of probable cause, and attendant intrusions, should not be authorized unless there is some assurance that the information on which they are based has been obtained in a reliable way by an honest or credible person. As applied to police officers, the rules focus on the way in which the information was acquired. As applied to informants, the rules focus both on the honesty or credibility of the informant and on the reliability of the way in which the information was acquired. Insofar as it is more complicated, an evaluation of affidavits based on hearsay involves a more difficult inquiry. This suggests a need to structure the inquiry in an effort to insure greater accuracy. The standards announced in Aguilar, as refined by Spinelli, fulfill that need. The standards inform the police of what information they have to provide and magistrates of what information they should demand. The standards also inform magistrates of the subsidiary findings they must make in order to arrive at an ultimate finding of probable cause. Spinelli, properly understood, directs the magistrate’s attention to the possibility that the presence of self-verifying detail might satisfy Aguilar1 s basis of knowledge prong and that corroboration of the details of a tip might satisfy Aguilar's veracity prong. By requiring police to provide certain crucial information to magistrates and by structuring magistrates’ probable-cause inquiries, Aguilar and Spinelli assure the magistrate’s role as an independent arbiter of probable cause, insure greater accuracy in probable-cause determinations, and advance the substantive value identified above.

Until today the Court has never squarely addressed the application of the Aguilar and Spinelli standards to tips from anonymous informants. Both Aguilar and Spinelli dealt with tips from informants known at least to the police. See also, e. g., Adams v. Williams, 407 U. S. 143, 146 (1972); United States v. Harris, 403 U. S. 573, 575 (1971); Whiteley v. Warden, 401 U. S., at 565; McCray v. Illinois, 386 U. S. *284300, 302 (1967); Jones v. United States, 362 U. S., at 268-269. And surely there is even more reason to subject anonymous informants’ tips to the tests established by Aguilar and Spinelli. By definition nothing is known about an anonymous informant’s identity, honesty, or reliability. One commentator has suggested that anonymous informants should be treated as presumptively unreliable. See Comment, Anonymous Tips, Corroboration, and Probable Cause: Reconciling the Spinelli!Draper Dichotomy in Illinois v. Gates, 20 Am. Crim. L. Rev. 99, 107 (1982). See also Adams v. Williams, supra, at 146 (suggesting that an anonymous telephone tip provides a weaker case for a Terry v. Ohio, 392 U. S. 1 (1968), stop than a tip from an informant known to the police who had provided information in the past); United States v. Harris, supra, at 599 (Harlan, J., dissenting) (“We cannot assume that the ordinary law-abiding citizen has qualms about [appearing before a magistrate]”). In any event, there certainly is no basis for treating anonymous informants as presumptively reliable. Nor is there any basis for assuming that the information provided by an anonymous informant has been obtained in a reliable way. If we are unwilling to accept conclusory allegations from the police, who are presumptively reliable, or from informants who are known, at least to the police, there cannot possibly be any rational basis for accepting conclusory allegations from anonymous informants.

To suggest that anonymous informants’ tips are subject to the tests established by Aguilar and Spinelli is not to suggest that they can never provide a basis for a finding of probable cause. It is conceivable that police corroboration of the details of the tip might establish the reliability of the informant under Aguilar’s, veracity prong, as refined in Spinelli, and that the details in the tip might be sufficient to qualify under the “self-verifying detail” test established by Spinelli as a means of satisfying Aguilar’s basis of knowledge prong. The Aguilar and Spinelli tests must be applied to anonymous informants’ tips, however, if we are to continue to insure *285that findings of probable cause, and attendant intrusions, are based on information provided by an honest or credible person who has acquired the information in a reliable way.6

In light of the important purposes served by Aguilar and Spinelli, I would not reject the standards they establish. If anything, I simply would make more clear that Spinelli, properly understood, does not depart in any fundamental way from the test established by Aguilar. For reasons I shall next state, I do not find persuasive the Court’s justifications for rejecting the test established by Aguilar and refined by Spinelli.

*286In rejecting the Aguilar-Spinelli standards, the Court suggests that a “totality-of-the-circumstances approach is far more consistent with our prior treatment of probable cause than is any rigid demand that specific ‘tests’ be satisfied by every informant’s tip.” Ante, at 230-231 (footnote omitted). In support of this proposition the Court relies on several cases that purportedly reflect this approach, ante, at 230-231, n. 6, 232-233, n. 7, and on the “practical, nontechnical,” ante, at 231, nature of probable cause.

Only one of the cases cited by the Court in support of its “totality of the circumstances” approach, Jaben v. United States, 381 U. S. 214 (1965), was decided subsequent to Aguilar. It is by no means inconsistent with Aguilar.7 The other three cases8 cited by the Court as supporting its *287totality-of-the-circumstances approach were decided before Aguilar. In any event, it is apparent from the Court’s discussion of them, see ante, at 232-233, n. 7, that they are not inconsistent with Aguilar.

In addition, one can concede that probable cause is a “practical, nontechnical” concept without betraying the values that Aguilar and Spinelli reflect. As noted, see supra, at 277-282, Aguilar and Spinelli require the police to provide magistrates with certain crucial information. They also provide structure for magistrates’ probable-cause inquiries. In so doing, Aguilar and Spinelli preserve the role of magistrates as independent arbiters of probable cause, insure greater accuracy in probable-cause determinations, and advance the substantive value of precluding findings of probable cause, and attendant intrusions, based on anything less than information from an honest or credible person who has acquired his information in a reliable way. Neither the standards nor their effects are inconsistent with a “practical, nontechnical” conception of probable cause. Once a magistrate has determined that he has information before him that he can reasonably say has been obtained in a reliable way by a credible person, he has ample room to use his common sense and to apply a practical, nontechnical conception of probable cause.

It also should be emphasized that cases such as Nathanson v. United States, 290 U. S. 41 (1933), and Giordenello v. United States, 357 U. S. 480 (1958), discussed supra, at 276-277, directly contradict the Court’s suggestion, ante, at 233, that a strong showing on one prong of the Aguilar test should compensate for a deficient showing on the other. If the conclusory allegations of a presumptively reliable police officer are insufficient to establish probable cause, there is no conceivable reason why the conclusory allegations of an anonymous informant should not be insufficient as well. Moreover, contrary to the Court’s implicit suggestion, Aguilar and Spinelli do not stand as an insuperable barrier to the use *288of even anonymous informants’ tips to establish probable cause. See supra, at 277-282. It is no justification for rejecting them outright that some courts may have employed an overly technical version of the Aguilar-Spinelli standards, see ante, at 234-235, and n. 9.

The Court also insists that the Aguilar-Spinelli standards must be abandoned because they are inconsistent with the fact that nonlawyers frequently serve as magistrates. Ante, at 235-236. To the contrary, the standards help to structure probable-cause inquiries and, properly interpreted, may actually help a nonlawyer magistrate in making a probable-cause determination. Moreover, the Aguilar and Spinelli tests are not inconsistent with deference to magistrates’ determinations of probable cause. Aguilar expressly acknowledged that reviewing courts “will pay substantial deference to judicial determinations of probable cause . . . .” 378 U. S., at 111. In Spinelli, the Court noted that it was not retreating from the proposition that magistrates’ determinations of probable cause “should be paid great deference by reviewing courts . . . .” 393 U. S., at 419. It is also noteworthy that the language from United States v. Ventresca, 380 U. S., at 108-109, which the Court repeatedly quotes, see ante, at 235, 236, and 237, n. 10, brackets the following passage, which the Court does not quote:

“This is not to say that probable cause can be made out by affidavits which are purely conclusory, stating only the affiant’s or an informer’s belief that probable cause exists without detailing any of the ‘underlying circumstances’ upon which that belief is based. See Aguilar v. Texas, supra. Recital of some of the underlying circumstances in the affidavit is essential if the magistrate is to perform his detached function and not serve merely as a rubber stamp for the police. However, where these circumstances are detailed, where reason for crediting the source of the information is given, and when a magistrate has found probable cause, the courts should not *289invalidate the warrant by interpreting the affidavit in a hypertechnical, rather than a commonsense, manner.” 380 U. S., at 108-109.9

At the heart of the Court’s decision to abandon Aguilar and Spinelli appears to be its belief that “the direction taken by decisions following Spinelli poorly serves ‘[tjhe most basic function of any government’: ‘to provide for the security of the individual and of his property.’” Ante, at 237. This conclusion rests on the judgment that Aguilar and Spinelli “seriously imped[e] the task of law enforcement,” ante, at 237, and render anonymous tips valueless in police work. Ibid. Surely, the Court overstates its case. See supra, at 287-288. But of particular concern to all Americans must be that the Court gives virtually no consideration to the value of insuring that findings of probable cause are based on information that a magistrate can reasonably say has been obtained in a reli*290able way by an honest or credible person. I share Justice White’s fear that the Court’s rejection of Aguilar and Spinelli and its adoption of a new totality-of-the-circumstances test, ante, at 238, “may foretell an evisceration of the probable-cause standard . . . Ante, at 272 (White, J., concurring in judgment).

Ill

The Court’s complete failure to provide any persuasive reason for rejecting Aguilar and Spinelli doubtlessly reflects impatience with what it perceives to be “overly technical” rules governing searches and seizures under the Fourth Amendment. Words such as “practical,” “nontechnical,” and “common sense,” as used in the Court’s opinion, are but code words for an overly permissive attitude towards police practices in derogation of the rights secured by the Fourth Amendment. Everyone shares the Court’s concern over the horrors of drug trafficking, but under our Constitution only measures consistent with the Fourth Amendment may be employed by government to cure this evil. We must be ever mindful of Justice Stewart’s admonition in Coolidge v. New Hampshire, 403 U. S. 443 (1971): “In times of unrest, whether caused by crime or racial conflict or fear of internal subversion, this basic law and the values that it represents may appear unrealistic or ‘extravagant’ to some. But the values were those of the authors of our fundamental constitutional concepts.” Id., at 455 (plurality opinion). In the same vein, Glasser v. United States, 315 U. S. 60 (1942), warned that “[sjteps innocently taken may, one by one, lead to the irretrievable impairment of substantial liberties.” Id., at 86.

Rights secured by the Fourth Amendment are particularly difficult to protect because their “advocates are usually criminals.” Draper v. United States, 358 U. S., at 314 (Douglas, J., dissenting). But the rules “we fashion [are] for the innocent and guilty alike.” Ibid. See also Kolender v. Lawson, 461 U. S. 352, 362, n. 1 (1983) (Brennan, J., concurring); Brinegar v. United States, 338 U. S., at 181 (Jackson, J., dis*291senting). By replacing Aguilar and Spinelli with a test that provides no assurance that magistrates, rather than the police, or informants, will make determinations of probable cause; imposes no structure on magistrates’ probable-cause inquiries; and invites the possibility that intrusions may be justified on less than reliable information from an honest or credible person, today’s decision threatens to “obliterate one of the most fundamental distinctions between our form of government, where officers are under the law, and the police-state where they are the law.” Johnson v. United States, 333 U. S., at 17.

Justice Stevens,

with whom Justice Brennan joins,

dissenting.

The fact that Lance and Sue Gates made a 22-hour nonstop drive from West Palm Beach, Florida, to Bloomingdale, Illinois, only a few hours after Lance had flown to Florida provided persuasive evidence that they were engaged in illicit activity. That fact, however, was not known to the judge when he issued the warrant to search their home.

What the judge did know at that time was that the anonymous informant had not been completely accurate in his or her predictions. The informant had indicated that “ ‘Sue . . . drives their car to Florida where she leaves it to be loaded up with drugs .... Sue fl[ies] back after she drops the car off in Florida.”’ 85 Ill. 2d 376, 379, 423 N. E. 2d 887, 888 (1981) (emphasis added). Yet Detective Mader’s affidavit reported that she “ ‘left the West Palm Beach area driving the Mercury northbound.’” 82 Ill. App. 3d 749, 757, 403 N. E. 2d 77, 82 (1980).

The discrepancy between the informant’s predictions and the facts known to Detective Mader is significant for three reasons. First, it cast doubt on the informant’s hypothesis that the Gates already had “ ‘over [$100,000] worth of drugs in their basement,’ ” 85 Ill. 2d, at 379, 423 N. E. 2d, at 888. The informant had predicted an itinerary that always kept one *292spouse in Bloomingdale, suggesting that the Gates did not want to leave their home unguarded because something valuable was hidden within. That inference obviously could not be drawn when it was known that the pair was actually together over a thousand miles from home.

Second, the discrepancy made the Gates’ conduct seem substantially less unusual than the informant had predicted it would be. It would have been odd if, as predicted, Sue had driven down to Florida on Wednesday, left the car, and flown right back to Illinois. But the mere facts that Sue was in West Palm Beach with the car,1 that she was joined by her husband at the Holiday Inn on Friday,2 and that the couple drove north together the next morning3 are neither unusual nor probative of criminal activity.

*293Third, the fact that the anonymous letter contained a material mistake undermines the reasonableness of relying on it as a basis for making a forcible entry into a private home.4

Of course, the activities in this case did not stop when the judge issued the warrant. The Gates drove all night to Bloomingdale, the officers searched the car and found 400 pounds of marihuana, and then they searched the house.5 However, none of these subsequent events may be considered in evaluating the warrant,6 and the search of the house was legal only if the warrant was valid. Vale v. Louisiana, 399 U. S. 30, 33-35 (1970). I cannot accept the Court’s casual conclusion that, before the Gates arrived in Bloomingdale, there was probable cause to justify a valid entry and search of a private home. No one knows who the informant in this case was, or what motivated him or her to write the note. Given that the note’s predictions were faulty in one *294significant respect, and were corroborated by nothing except ordinary innocent activity, I must surmise that the Court’s evaluation of the warrant’s validity has been colored by subsequent events.7

Although the foregoing analysis is determinative as to the house search, the car search raises additional issues because “there is a constitutional difference between houses and cars.” Chambers v. Maroney, 399 U. S. 42, 52 (1970). Cf. Payton v. New York, 445 U. S. 573, 589-590 (1980). An officer who has probable cause to suspect that a highly movable automobile contains contraband does not need a valid warrant in order to search it. This point was developed in our opinion in United States v. Ross, 456 U. S. 798 (1982), which was not decided until after the Illinois Supreme Court rendered its decision in this case. Under Ross, the car search may have been valid if the officers had probable cause after the Gates arrived.

In apologizing for its belated realization that we should not have ordered reargument in this case, the Court today shows high regard for the appropriate relationship of this Court to state courts. Ante, at 221-222. When the Court discusses the merits, however, it attaches no weight to the conclusions of the Circuit Judge of Du Page County, Illinois, of the three judges of the Second District of the Illinois Appellate Court, or of the five justices of the Illinois Supreme Court, all of whom concluded that the warrant was not based on probable cause. In a fact-bound inquiry of this sort, the judgment of three levels of state courts, all of which are better able to evaluate the probable reliability of anonymous informants in *295Bloomingdale, Illinois, than we are, should be entitled to at least a presumption of accuracy.8 I would simply vacate the judgment of the Illinois Supreme Court and remand the case for reconsideration in the light of our intervening decision in United States v. Ross.

Justice White

delivered the opinion of the Court.

We granted certiorari in this case to examine the appropriateness of the exclusionary rule as a remedy for searches carried out in violation of the Fourth Amendment by public school authorities. Our consideration of the proper application of the Fourth Amendment to the public schools, however, has led us to conclude that the search that gave rise to *328the case now before us did not violate the Fourth Amendment. Accordingly, we here address only the questions of the proper standard for assessing the legality of searches conducted by public school officials and the application of that standard to the facts of this case.

I

On March 7, 1980, a teacher at Piscataway High School in Middlesex County, N. J., discovered two girls smoking in a lavatory. One of the two girls was the respondent T. L. 0., who at that time was a 14-year-old high school freshman. Because smoking in the lavatory was a violation of a school rule, the teacher took the two girls to the Principal’s office, where they met with Assistant Vice Principal Theodore Choplick. In response to questioning by Mr. Choplick, T. L. O.’s companion admitted that she had violated the rule. T. L. 0., however, denied that she had been smoking in the lavatory and claimed that she did not smoke at all.

Mr. Choplick asked T. L. O. to come into his private office and demanded to see her purse. Opening the purse, he found a pack of cigarettes, which he removed from the purse and held before T. L. O. as he accused her of having lied to him. As he reached into the purse for the cigarettes, Mr. Choplick also noticed a package of cigarette rolling papers. In his experience, possession of rolling papers by high school students was closely associated with the use of marihuana. Suspecting that a closer examination of the purse might yield further evidence of drug use, Mr. Choplick proceeded to search the purse thoroughly. The search revealed a smáll amount of marihuana, a pipe, a number of empty plastic bags, a substantial quantity of money in one-dollar bills, an index card that appeared to be a list of students who owed T. L. O. money, and two letters that implicated T. L. O. in marihuana dealing.

Mr. Choplick notified T. L. O.’s mother and the police, and turned the evidence of drug dealing over to the police. At *329the request of the police, T. L. O.’s mother took her daughter to police headquarters, where T. L. O. confessed that she had been selling marihuana at the high school. On the basis of the confession and the evidence seized by Mr. Choplick, the State brought delinquency charges against T. L. O. in the Juvenile and Domestic Relations Court of Middlesex County.1 Contending that Mr. Choplick’s search of her purse violated the Fourth Amendment, T. L. O. moved to suppress the evidence found in her purse as well as her confession, which, she argued, was tainted by the allegedly unlawful search. The Juvenile Court denied the motion to suppress. State ex rel. T. L. O., 178 N. J. Super. 329, 428 A. 2d 1327 (1980). Although the court concluded that the Fourth Amendment did apply to searches carried out by school officials, it held that

“a school official may properly conduct a search of a student’s person if the official has a reasonable suspicion that a crime has been or is in the process of being committed, or reasonable cause to believe that the search is necessary to maintain school discipline or enforce school policies.” Id., at 341, 428 A. 2d, at 1333 (emphasis in original).

Applying this standard, the court concluded that the search conducted by Mr. Choplick was a reasonable one. The initial decision to open the purse was justified by Mr. Choplick’s well-founded suspicion that T. L. O. had violated the rule forbidding smoking in the lavatory. Once the purse *330was open, evidence of marihuana violations was in plain view, and Mr. Choplick was entitled to conduct a thorough search to determine the nature and extent of T. L. O.’s drug-related activities. Id., at 343, 428 A. 2d, at 1334. Having denied the motion to suppress, the court on March 23, 1981, found T. L. O. to be a delinquent and on January 8, 1982, sentenced her to a year’s probation.

On appeal from the final judgment of the Juvenile Court, a divided Appellate Division affirmed the trial court’s finding that there had been no Fourth Amendment violation, but vacated the adjudication of delinquency and remanded for a determination whether T. L. O. had knowingly and voluntarily waived her Fifth Amendment rights before confessing. State ex rel. T. L. O., 185 N. J. Super. 279, 448 A. 2d 493 (1982). T. L. O. appealed the Fourth Amendment ruling, and the Supreme Court of New Jersey reversed the judgment of the Appellate Division and ordered the suppression of the evidence found in T. L. O.’s purse. State ex rel. T. L. O., 94 N. J. 331, 463 A. 2d 934 (1983).

The New Jersey Supreme Court agreed with the lower courts that the Fourth Amendment applies to searches conducted by school officials. The court also rejected the State of New Jersey’s argument that the exclusionary rule should not be employed to prevent the use in juvenile proceedings of evidence unlawfully seized by school officials. Declining to consider whether applying the rule to the fruits of searches by school officials would have any deterrent value, the court held simply that the precedents of this Court establish that “if an official search violates constitutional rights, the evidence is not admissible in criminal proceedings.” Id., at 341, 463 A. 2d, at 939 (footnote omitted).

With respect to the question of the legality of the search before it, the court agreed with the Juvenile Court that a warrantless search by a school official does not violate the Fourth Amendment so long as the official “has reasonable grounds to believe that a student possesses evidence of illegal *331activity or activity that would interfere with school discipline and order.” Id., at 346, 463 A. 2d, at 941-942. However, the court, with two justices dissenting, sharply disagreed with the Juvenile Court’s conclusion that the search of the purse was reasonable. According to the majority, the contents of T. L. O.’s purse had no bearing on the accusation against T. L. 0., for possession of cigarettes (as opposed to smoking them in the lavatory) did not violate school rules, and a mere desire for evidence that would impeach T. L. O.’s claim that she did not smoke cigarettes could not justify the search. Moreover, even if a reasonable suspicion that T. L. O. had cigarettes in her purse would justify a search, Mr. Choplick had no such suspicion, as no one had furnished him with any specific information that there were cigarettes in the purse. Finally, leaving aside the question whether Mr. Choplick was justified in opening the purse, the court held that the evidence of drug use that he saw inside did not justify the extensive “rummaging” through T. L. O.’s papers and effects that followed. Id., at 347, 463 A. 2d, at 942-943.

We granted the State of New Jersey’s petition for certio-rari. 464 U. S. 991 (1983). Although the State had argued in the Supreme Court of New Jersey that the search of T. L. O.’s purse did not violate the Fourth Amendment, the petition for certiorari raised only the question whether the exclusionary rule should operate to bar consideration in juvenile delinquency proceedings of evidence unlawfully seized by a school official without the involvement of law enforcement officers. When this case was first argued last Term, the State conceded for the purpose of argument that the standard devised by the New Jersey Supreme Court for determining the legality of school searches was appropriate and that the court had correctly applied that standard; the State contended only that the remedial purposes of the exclusionary rule were not well served by applying it to searches conducted by public authorities not primarily engaged in law enforcement.

*332Although we originally granted certiorari to decide the issue of the appropriate remedy in juvenile court proceedings for unlawful school searches, our doubts regarding the wisdom of deciding that question in isolation from the broader question of what limits, if any, the Fourth Amendment places on the activities of school authorities prompted us to order reargument on that question.2 Having heard argument on *333the legality of the search of T. L. O.’s purse, we are satisfied that the search did not violate the Fourth Amendment.3

II

In determining whether the search at issue in this case violated the Fourth Amendment, we are faced initially with the question whether that Amendment’s prohibition on unreasonable searches and seizures applies to searches conducted by public school officials. We hold that it does.

*334It is now beyond dispute that “the Federal Constitution, by virtue of the Fourteenth Amendment, prohibits unreasonable searches and seizures by state officers.” Elkins v. United States, 364 U. S. 206, 213 (1960); accord, Mapp v. Ohio, 367 U. S. 643 (1961); Wolf v. Colorado, 338 U. S. 25 (1949). Equally indisputable is the proposition that the Fourteenth Amendment protects the rights of students against encroachment by public school officials:

“The Fourteenth Amendment, as now applied to the States, protects the citizen against the State itself and all of its creatures — Boards of Education not excepted. These have, of course, important, delicate, and highly discretionary functions, but none that they may not perform within the limits of the Bill of Rights. That they are educating the young for citizenship is reason for scrupulous protection of Constitutional freedoms of the individual, if we are not to strangle the free mind at its source and teach youth to discount important principles of our government as mere platitudes.” West Virginia State Bd. of Ed. v. Barnette, 319 U. S. 624, 637 (1943).

These two propositions — that the Fourth Amendment applies to the States through the Fourteenth Amendment, and that the actions of public school officials are subject to the limits placed on state action by the Fourteenth Amendment — might appear sufficient to answer the suggestion that the Fourth Amendment does not proscribe unreasonable searches by school officials. On reargument, however, the State of New Jersey has argued that the history of the Fourth Amendment indicates that the Amendment was intended to regulate only searches and seizures carried out by law enforcement officers; accordingly, although public school officials are concededly state agents for purposes of the Fourteenth Amendment, the Fourth Amendment creates no rights enforceable against them.4

*335It may well be true that the evil toward which the Fourth Amendment was primarily directed was the resurrection of the pre-Revolutionary practice of using general warrants or “writs of assistance” to authorize searches for contraband by officers of the Crown. See United States v. Chadwick, 433 U. S. 1, 7-8 (1977); Boyd v. United States, 116 U. S. 616, 624-629 (1886). But this Court has never limited the Amendment’s prohibition on unreasonable searches and seizures to operations conducted by the police. Rather, the Court has long spoken of the Fourth Amendment’s strictures as restraints imposed upon “governmental action” — that is, “upon the activities of sovereign authority.” Burdeau v. McDowell, 256 U. S. 465, 475 (1921). Accordingly, we have held the Fourth Amendment applicable to the activities of civil as well as criminal authorities: building inspectors, see Camara v. Municipal Court, 387 U. S. 523, 528 (1967), Occupational Safety and Health Act inspectors, see Marshall v. Barlow’s, Inc., 436 U. S. 307, 312-313 (1978), and even firemen entering privately owned premises to battle a fire, see Michigan v. Tyler, 436 U. S. 499, 506 (1978), are all subject to the restraints imposed by the Fourth Amendment. As we observed in Camara v. Municipal Court, supra, “[t]he basic purpose of this Amendment, as recognized in countless decisions of this Court, is to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials.” 387 U. S., at 528. Because the individual’s interest in privacy and personal security “suffers whether the government’s motivation is to investigate violations of criminal laws or breaches of other statutory or regulatory standards,” Marshall v. Barlow’s, Inc., supra, at 312-313, it would be “anomalous to say that the individual and his private property are fully protected by the Fourth Amendment only when the individual is suspected of criminal behavior.” Camara v. Municipal Court, supra, at 530.

*336Notwithstanding the general applicability of the Fourth Amendment to the activities of civil authorities, a few courts have concluded that school officials are exempt from the dictates of the Fourth Amendment by virtue of the special nature of their authority over schoolchildren. See, e. g., R. C. M. v. State, 660 S. W. 2d 552 (Tex. App. 1983). Teachers and school administrators, it is said, act in loco parentis in their dealings with students: their authority is that of the parent, not the State, and is therefore not subject to the limits of the Fourth Amendment. Ibid.

Such reasoning is in tension with contemporary reality and the teachings of this Court. We have held school officials subject to the commands of the First Amendment, see Tinker v. Des Moines Independent Community School District, 393 U. S. 503 (1969), and the Due Process Clause of the Fourteenth Amendment, see Goss v. Lopez, 419 U. S. 565 (1975). If school authorities are state actors for purposes of the constitutional guarantees of freedom of expression and due process, it is difficult to understand why they should be deemed to be exercising parental rather than public authority when conducting searches of their students. More generally, the Court has recognized that “the concept of parental delegation” as a source of school authority is not entirely “consonant with compulsory education laws.” Ingraham v. Wright, 430 U. S. 651, 662 (1977). Today’s public school officials do not merely exercise authority voluntarily conferred on them by individual parents; rather, they act in furtherance of publicly mandated educational and disciplinary policies. See, e. g., the opinion in State ex rel. T. L. O., 94 N. J., at 343, 463 A. 2d, at 934, 940, describing the New Jersey statutes regulating school disciplinary policies and establishing the authority of school officials over their students. In carrying out searches and other disciplinary functions pursuant to such policies, school officials act as representatives of the State, not merely as surrogates for the parents, and they *337cannot claim the parents’ immunity from the strictures of the Fourth Amendment.

Ill

To hold that the Fourth Amendment applies to searches conducted by school authorities is only to begin the inquiry into the standards governing such searches. Although the underlying command of the Fourth Amendment is always that searches and seizures be reasonable, what is reasonable depends on the context within which a search takes place. The determination of the standard of reasonableness governing any specific class of searches requires “balancing the need to search against the invasion which the search entails.” Camara v. Municipal Court, supra, at 536-537. On one side of the balance are arrayed the individual’s legitimate expectations of privacy and personal security; on the other, the government’s need for effective methods to deal with breaches of public order.

We have recognized that even a limited search of the person is a substantial invasion of privacy. Terry v. Ohio, 392 U. S. 1, 24-25 (1967). We have also recognized that searches of closed items of personal luggage are intrusions on protected privacy interests, for “the Fourth Amendment pro-' vides protection to the owner of every container that conceals" its contents from plain view.” United States v. Ross, 456 U. S. 798, 822-823 (1982). A search of a child’s person or of' a closed purse or other bag carried on her person,5 no less *338than a similar search carried out on an adult, is undoubtedly a severe violation of subjective expectations of privacy.

. Of course, the Fourth Amendment does not protect subjective expectations of privacy that are unreasonable or otherwise “illegitimate.” See, e. g., Hudson v. Palmer, 468 U. S. 517 (1984); Rawlings v. Kentucky, 448 U. S. 98 (1980). To receive the protection of the Fourth Amendment, an expectation of privacy must be one that society is “prepared to recognize as legitimate.” Hudson v. Palmer, supra, at 526. The State of New Jersey has argued that because of the pervasive supervision to which children in the schools are necessarily subject, a child has virtually no legitimate expectation of privacy in articles of personal property “unnecessarily” carried into a school. This argument has two factual premises: (1) the fundamental incompatibility of expectations of privacy with the maintenance of a sound educational environment; and (2) the minimal interest of the child in bringing any items of personal property into the school. Both premises are severely flawed.

Although this Court may take notice of the difficulty of maintaining discipline in the public schools today, the situation is not so dire that students in the schools may claim no legitimate expectations of privacy. We have recently recognized that the need to maintain order in a prison is such that prisoners retain no legitimate expectations of privacy in their cells, but it goes almost without saying that “[tjhe prisoner and the schoolchild stand in wholly different circumstances, separated by the harsh facts of criminal conviction and incarceration.” Ingraham v. Wright, supra, at 669. We are not *339yet ready to hold that the schools and the prisons need be equated for purposes of the Fourth Amendment.

Nor does the State’s suggestion that children have no legitimate need to bring personal property into the schools seem well anchored in reality. Students at a minimum must bring to school not only the supplies needed for their studies, but also keys, money, and the necessaries of personal hygiene and grooming. In addition, students may carry on their persons or in purses or wallets such nondisruptive yet highly personal items as photographs, letters, and diaries. Finally, students may have perfectly legitimate reasons to carry with them articles of property needed in connection with extracurricular or recreational activities. In short, schoolchildren may find it necessary to carry with them a variety of legitimate, noncontraband items, and there is no reason to conclude that they have necessarily waived all rights to privacy in such items merely by bringing them onto school grounds.

Against the child’s interest in privacy must be set the substantial interest of teachers and administrators in maintaining discipline in the classroom and on school grounds. Maintaining order in the classroom has never been easy, but in recent years, school disorder has often taken particularly ugly forms: drug use and violent crime in the schools have become major social problems. See generally 1 NIE, U. S. Dept, of Health, Education and Welfare, Violent Schools— Safe Schools: The Safe School Study Report to the Congress (1978). Even in schools that have been spared the most severe disciplinary problems, the preservation of order and a proper educational environment requires close supervision of schoolchildren, as well as the enforcement of rules against conduct that would be perfectly permissible if undertaken by an adult. “Events calling for discipline are frequent occurrences and sometimes require immediate, effective action.” Goss v. Lopez, 419 U. S., at 580. Accordingly, we have rec*340ognized that maintaining security and order in the schools requires a certain degree of flexibility in school disciplinary procedures, and we have respected the value of preserving the informality of the student-teacher relationship. See id., at 582-583; Ingraham v. Wright, 430 U. S., at 680-682.

How, then, should we strike the balance between the schoolchild’s legitimate expectations of privacy and the school’s equally legitimate need to maintain an environment in which learning can take place? It is evident that the school setting requires some easing of the restrictions to which searches by public authorities are ordinarily subject. The warrant requirement, in particular, is unsuited to the school environment: requiring a teacher to obtain a warrant before searching a child suspected of an infraction of school rules (or of the criminal law) would unduly interfere with the maintenance of the swift and informal disciplinary procedures needed in the schools. Just as we have in other cases dispensed with the warrant requirement when “the burden of obtaining a warrant is likely to frustrate the governmental purpose behind the search,” Camara v. Municipal Court, 387 U. S., at 532-533, we hold today that school officials need not obtain a warrant before searching a student who is under their authority.

The school setting also requires some modification of the level of suspicion of illicit activity needed to justify a search. Ordinarily, a search — even one that may permissibly be carried out without a warrant — must be based upon “probable cause” to believe that a violation of the law has occurred. See, e. g., Almeida-Sanchez v. United States, 413 U. S. 266, 273 (1973); Sibron v. New York, 392 U. S. 40, 62-66 (1968). However, “probable cause” is not an irreducible requirement of a valid search. The fundamental command of the Fourth Amendment is that searches and seizures be reasonable, and although “both the concept of probable cause and the requirement of a warrant bear on the reasonableness of a search, . . . in certain limited circumstances neither is required.” Almeida-Sanchez v. United States, supra, at 277 (Powell, *341J., concurring). Thus, we have in a number of cases recognized the legality of searches and seizures based on suspicions that, although “reasonable,” do not rise to the level of probable cause. See, e. g., Terry v. Ohio, 392 U. S. 1 (1968); United States v. Brignoni-Ponce, 422 U. S. 873, 881 (1975); Delaware v. Prouse, 440 U. S. 648, 654-655 (1979); United States v. Martinez-Fuerte, 428 U. S. 543 (1976); cf. Camara v. Municipal Court, supra, at 534-539. Where a careful balancing of governmental and private interests suggests that the public interest is best served by a Fourth Amendment standard of reasonableness that stops short of probable cause, we have not hesitated to adopt such a standard.

We join the majority of courts that have examined this issue6 in concluding that the accommodation of the privacy interests of schoolchildren with the substantial need of teachers and administrators for freedom to maintain order in the schools does not require strict adherence to the requirement that searches be based on probable cause to believe that the subject of the search has violated or is violating the law. Rather, the legality of a search of a student should depend simply on the reasonableness, under all the circumstances, of the search. Determining the reasonableness of any search involves a twofold inquiry: first, one must consider “whether the . . . action was justified at its inception,” Terry v. Ohio, 392 U. S., at 20; second, one must determine whether the search as actually conducted “was reasonably related in scope to the circumstances which justified the interference in the first place,” ibid. Under ordinary circumstances, a search of a student by a teacher or other school official7 will be *342“justified at its inception” when there are reasonable grounds for suspecting that the search will turn up evidence that the student has violated or is violating either the law or the rules of the school.8 Such a search will be permissible in its scope when the measures adopted are reasonably related to the objectives of the search and not excessively intrusive in light of the age and sex of the student and the nature of the infraction.9

This standard will, we trust, neither unduly burden the efforts of school authorities to maintain order in their schools *343nor authorize unrestrained intrusions upon the privacy of schoolchildren. By focusing attention on the question of reasonableness, the standard will spare teachers and school administrators the necessity of schooling themselves in the niceties of probable cause and permit them to regulate their conduct according to the dictates of reason and common sense. At the same time, the reasonableness standard should ensure that the interests of students will be invaded no more than is necessary to achieve the legitimate end of preserving order in the schools.

IV

There remains the question of the legality of the search in this case. We recognize that the “reasonable grounds” standard applied by the New Jersey Supreme Court in its consideration of this question is not substantially different from the standard that we have adopted today. Nonetheless, we believe that the New Jersey court’s application of that standard to strike down the search of T. L. O.’s purse reflects a somewhat crabbed notion of reasonableness. Our review of the facts surrounding the search leads us to conclude that the search was in no sense unreasonable for Fourth Amendment purposes.10

The incident that gave rise to this case actually involved two separate searches, with the first — the search for cigarettes — providing the suspicion that gave rise to the sec*344ond — the search for marihuana. Although it is the fruits of the second search that are at issue here, the validity of the search for marihuana must depend on the reasonableness of the initial search for cigarettes, as there would have been no reason to suspect that T. L. O. possessed marihuana had the first search not taken place. Accordingly, it is to the search for cigarettes that we first turn our attention.

The New Jersey Supreme Court pointed to two grounds for its holding that the search for cigarettes was unreasonable. First, the court observed that possession of cigarettes was not in itself illegal or a violation of school rules. Because the contents of T. L. O.’s purse would therefore have “no direct bearing on the infraction” of which she was accused (smoking in a lavatory where smoking was prohibited), there was no reason to search her purse.11 Second, even assuming that a search of T. L. O.’s purse might under some circumstances be reasonable in light of the accusation made against T. L. 0., the New Jersey court concluded that Mr. Choplick in this particular case had no reasonable grounds to suspect that T. L. O. had cigarettes in her purse. At best, accord*345ing to the court, Mr. Chopliek had “a good hunch.” 94 N. J., at 347, 463 A. 2d, at 942.

Both these conclusions are implausible. T. L. O. had been accused of smoking, and had denied the accusation in the strongest possible terms when she stated that she did not smoke at all. Surely it cannot be said that under these circumstances, T. L. O.’s possession of cigarettes would be irrelevant to the charges against her or to her response to those charges. T. L. O.’s possession of cigarettes, once it was discovered, would both corroborate the report that she had been smoking and undermine the credibility of her defense to the charge of smoking. To be sure, the discovery of the cigarettes would not prove that T. L. O. had been smoking in the lavatory; nor would it, strictly speaking, necessarily be inconsistent with her claim that she did not smoke at all. But it is universally recognized that evidence, to be relevant to an inquiry, need not conclusively prove the ultimate fact in issue, but only have “any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.” Fed. Rule Evid. 401. The relevance of T. L. O.’s possession of cigarettes to the question whether she had been smoking and to the credibility of her denial that she smoked supplied the necessary “nexus” between the item searched for and the infraction under investigation. See Warden v. Hayden, 387 U. S. 294, 306-307 (1967). Thus, if Mr. Chopliek in fact had a reasonable suspicion that T. L. O. had cigarettes in her purse, the search was justified despite the fact that the cigarettes, if found, would constitute “mere evidence” of a violation. Ibid.

Of course, the New Jersey Supreme Court also held that Mr. Chopliek had no reasonable suspicion that the purse would contain cigarettes. This conclusion is puzzling. A teacher had reported that T. L. O. was smoking in the lavatory. Certainly this report gave Mr. Chopliek reason to suspect that T. L. O. was carrying cigarettes with her; and *346if she did have cigarettes, her purse was the obvious place in which to find them. Mr. Choplick’s suspicion that there were cigarettes in the purse was not an “inchoate and un-particularized suspicion or ‘hunch,’” Terry v. Ohio, 392 U. S., at 27; rather, it was the sort of “common-sense conclusio[n] about human behavior” upon which “practical people” — including government officials — are entitled to rely. United States v. Cortez, 449 U. S. 411, 418 (1981). Of course, even if the teacher’s report were true, T. L. O. might not have had a pack of cigarettes with her; she might have borrowed a cigarette from someone else or have been sharing a cigarette with another student. But the requirement of reasonable suspicion is not a requirement of absolute certainty: “sufficient probability, not certainty, is the touchstone of reasonableness under the Fourth Amendment. ...” Hill v. California, 401 U. S. 797, 804 (1971). Because the hypothesis that T. L. O. was carrying cigarettes in her purse was itself not unreasonable, it is irrelevant that other hypotheses were also consistent with the teacher’s accusation. Accordingly, it cannot be said that Mr. Choplick acted unreasonably when he examined T. L. O.’s purse to see if it contained cigarettes.12

*347Our conclusion that Mr. Choplick’s decision to open T. L. O.’s purse was reasonable brings us to the question of the further search for marihuana once the pack of cigarettes was located. The suspicion upon which the search for marihuana was founded was provided when Mr. Choplick observed a package of rolling papers in the purse as he removed the pack of cigarettes. Although T. L. O. does not dispute the reasonableness of Mr. Choplick’s belief that the rolling papers indicated the presence of marihuana, she does contend that the scope of the search Mr. Choplick conducted exceeded permissible bounds when he seized and read certain letters that implicated T. L. O. in drug dealing. This argument, too, is unpersuasive. The discovery of the rolling papers concededly gave rise to a reasonable suspicion that T. L. O. was carrying marihuana as well as cigarettes in her purse. This suspicion justified further exploration of T. L. O.’s purse, which turned up more evidence of drug-related activities: a pipe, a number of plastic bags of the type commonly used to store marihuana, a small quantity of marihuana, and a fairly substantial amount of money. Under these circumstances, it was not unreasonable to extend the search to a separate zippered compartment of the purse; and when a search of that compartment revealed an index card containing a list of “people who owe me money” as well as two letters, the inference that T. L. O. was involved in marihuana trafficking was substantial enough to justify Mr. Choplick in examining the letters to determine whether they contained any further evidence. In short, we cannot conclude that the search for marihuana was unreasonable in any respect.

Because the search resulting in the discovery of the evidence of marihuana dealing by T. L. O. was reasonable, the New Jersey Supreme Court’s decision to exclude that evi*348dence from T. L. O.’s juvenile delinquency proceedings on Fourth Amendment grounds was erroneous. Accordingly, the judgment of the Supreme Court of New Jersey is

Reversed.

Justice Powell,

with whom Justice O’Connor joins,

concurring.

I agree with the Court’s decision, and generally with its opinion. I would place greater emphasis, however, on the special characteristics of elementary and secondary schools that make it unnecessary to afford students the same constitutional protections granted adults and juveniles in a nonschool setting.

In any realistic sense, students within the school environment have a lesser expectation of privacy than members of the population generally. They spend the school hours in close association with each other, both in the classroom and during recreation periods. The students in a particular class often know each other and their teachers quite well. Of necessity, teachers have a degree of familiarity with, and authority over, their students that is unparalleled except perhaps in the relationship between parent and child. It is simply unrealistic to think that students have the same subjective expectation of privacy as the population generally. But for purposes of deciding this case, I can assume that children in school — no less than adults — have privacy interests that society is prepared to recognize as legitimate.

However one may characterize their privacy expectations, students properly are afforded some constitutional protections. In an often quoted statement, the Court said that students do not “shed their constitutional rights ... at the schoolhouse gate.” Tinker v. Des Moines Independent Community School District, 393 U. S. 503, 506 (1969). The Court also has “emphasized the need for affirming the comprehensive authority of the states and of school officials . . . *349to prescribe and control conduct in the schools.” Id., at 507. See also Epperson v. Arkansas, 393 U. S. 97, 104 (1968). The Court has balanced the interests of the student against the school officials’ need to maintain discipline by recognizing qualitative differences between the constitutional remedies to which students and adults are entitled.

In Goss v. Lopez, 419 U. S. 565 (1975), the Court recognized a constitutional right to due process, and yet was careful to limit the exercise of this right by a student who challenged a disciplinary suspension. The only process found to be “due” was notice and a hearing described as “rudimentary”; it amounted to no more than “the disciplinarian . . . informally discussing] the alleged misconduct with the student minutes after it has occurred.” Id., at 581-582. In Ingraham v. Wright, 430 U. S. 651 (1977), we declined to extend the Eighth Amendment to prohibit the use of corporal punishment of schoolchildren as authorized by Florida law. We emphasized in that opinion that familiar constraints in the school, and also in the community, provide substantial protection against the violation of constitutional rights by school authorities. “[A]t the end of the school day, the child is invariably free to return home. Even while at school, the child brings with him the support of family and friends and is rarely apart from teachers and other pupils who may witness and protest any instances of mistreatment.” Id., at 670. The Ingraham Court further pointed out that the “openness of the public school and its supervision by the community afford significant safeguards” against the violation of constitutional rights. Ibid.

The special relationship between teacher and student also distinguishes the setting within which schoolchildren operate. Law enforcement officers function as adversaries of criminal suspects. These officers have the responsibility to investigate criminal activity, to locate and arrest those who violate our laws, and to facilitate the charging and bringing of such persons to trial. Rarely does this type of adversarial *350relationship exist between school authorities and pupils.1 Instead,'there is a commonality of interests between teachers and their pupils. The attitude of the typical teacher is one of personal responsibility for the student’s welfare as well as for his education.

The primary duty of school officials and teachers, as the Court states, is the education and training of young people. A State has a compelling interest in assuring that the schools meet this responsibility. Without first establishing discipline and maintaining order, teachers cannot begin to educate their students. And apart from education, the school has the obligation to protect pupils from mistreatment by other children, and also to protect teachers themselves from violence by the few students whose conduct in recent years has prompted national concern. For me, it would be unreasonable and at odds with history to argue that the full panoply of constitutional rules applies with the same force and effect in the schoolhouse as it does in the enforcement of criminal laws.2

In sum, although I join the Court’s opinion and its holding,3 my emphasis is somewhat different.

*351Justice Blackmun,

concurring in the judgment.

I join the judgment of the Court and agree with much that is said in its opinion. I write separately, however, because I believe the Court omits a crucial step in its analysis of whether a school search must be based upon probable cause. The Court correctly states that we have recognized limited exceptions to the probable-cause requirement “[w]here a careful balancing of governmental and private interests suggests that the public interest is best served” by a lesser standard. Ante, at 341. I believe that we have used such a balancing test, rather than strictly applying the Fourth Amendment’s Warrant and Probable-Cause Clause, only when we were confronted with “a special law enforcement need for greater flexibility.” Florida v. Royer, 460 U. S. 491, 514 (1983) (Blackmun, J., dissenting). I pointed out in United States v. Place, 462 U. S. 696 (1983):

“While the Fourth Amendment speaks in terms of freedom from unreasonable [searches], the Amendment does not leave the reasonableness of most [searches] to the judgment of courts or government officers; the Framers of the Amendment balanced the interests involved and decided that a [search] is reasonable only if supported by a judicial warrant based on probable cause. See Texas v. Brown, 460 U. S. 730, 744-745 (1983) (Powell, J., concurring); United States v. Rabinomtz, 339 U. S. 56, 70 (1950) (Frankfurter, J., dissenting).” Id., at 722 (opinion concurring in judgment).

See also Dunaway v. New York, 442 U. S. 200, 213-214 (1979); United States v. United States District Court, 407 U. S. 297, 315-316 (1972). Only in those exceptional circumstances in which special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable, is a court entitled to substitute its balancing of interests for that of the Framers.

*352Thus, for example, in determining that police can conduct a limited “stop and frisk” upon less than probable cause, this Court relied upon the fact that “as a practical matter” the stop and frisk could not be subjected to a warrant and probable-cause requirement, because a law enforcement officer must be able to take immediate steps to assure himself that the person he has stopped to question is not armed with a weapon that could be used against him. Terry v. Ohio, 392 U. S. 1, 20-21, 23-24 (1968). Similarly, this Court’s holding that a roving Border Patrol may stop a car and briefly question its occupants upon less than probable cause was based in part upon “the absence of practical alternatives for policing the border.” United States v. Brignoni-Ponce, 422 U. S. 873, 881 (1975). See also Michigan v. Long, 463 U. S. 1032, 1049, n. 14 (1983); United States v. Martinez-Fuerte, 428 U. S. 543, 557 (1976); Camara v. Municipal Court, 387 U. S. 523, 537 (1967).

The Court’s implication that the balancing test is the rule rather than the exception is troubling for me because it is unnecessary in this case. The elementary and secondary school setting presents a special need for flexibility justifying a departure from the balance struck by the Framers. As Justice Powell notes, “[without first establishing discipline and maintaining order, teachers cannot begin to educate their students.” Ante, at 350. Maintaining order in the classroom can be a difficult task. A single teacher often must watch over a large number of students, and, as any parent knows, children at certain ages are inclined to test the outer boundaries of acceptable conduct and to imitate the misbehavior of a peer if that misbehavior is not dealt with quickly. Every adult remembers from his own schooldays the havoc a water pistol or peashooter can wreak until it is taken away. Thus, the Court has recognized that “[ejvents calling for discipline are frequent occurrences and sometimes require immediate, effective action.” Goss v. Lopez, 419 U. S. 565, 580 (1975). Indeed, because drug use and possession of weapons have become increasingly common *353among young people, an immediate response frequently is required not just to maintain an environment conducive to learning, but to protect the very safety of students and school personnel.

Such immediate action obviously would not be possible if a teacher were required to secure a warrant before searching a student. Nor would it be possible if a teacher could not conduct a necessary search until the teacher thought there was probable cause for the search. A teacher has neither the training nor the day-to-day experience in the complexities of probable cause that a law enforcement officer possesses, and is ill-equipped to make a quick judgment about the existence of probable cause. The time required for a teacher to ask the questions or make the observations that are necessary to turn reasonable grounds into probable cause is time during which the teacher, and other students, are diverted from the essential task of education. A teacher’s focus is, and should be, on teaching and helping students, rather than on developing evidence against a particular troublemaker.

Education “is perhaps the most important function” of government, Brown v. Board of Education, 347 U. S. 483, 493 (1954), and government has a heightened obligation to safeguard students whom it compels to attend school. The special need for an immediate response to behavior that threatens either the safety of schoolchildren and teachers or the educational process itself justifies the Court in excepting school searches from the warrant and probable-cause requirement, and in applying a standard determined by balancing the relevant interests. I agree with the standard the Court has announced, and with its application of the standard to the facts of this case. I therefore concur in its judgment.

Justice Brennan,

with whom Justice Marshall joins,

concurring in part and dissenting in part.

I fully agree with Part II of the Court’s opinion. Teachers, like all other government officials, must conform their *354conduct to the Fourth Amendment’s protections of personal privacy and personal security. As Justice Stevens points out, post, at 373-374, 385-386, this principle is of particular importance when applied to schoolteachers, for children learn as much by example as by exposition. It would be incongruous and futile to charge teachers with the task of embuing their students with an understanding of our system of constitutional democracy, while at the same time immunizing those same teachers from the need to respect constitutional protections. See Board of Education v. Pico, 457 U. S. 853, 864-865 (1982) (plurality opinion); West Virginia State Board of Education v. Barnette, 319 U. S. 624, 637 (1943).

I do not, however, otherwise join the Court’s opinion. Today’s decision sanctions school officials to conduct full-scale searches on a “reasonableness” standard whose only definite content is that it is not the same test as the “probable cause” standard found in the text of the Fourth Amendment. In adopting this unclear, unprecedented, and unnecessary departure from generally applicable Fourth Amendment standards, the Court carves out a broad exception to standards that this Court has developed over years of considering Fourth Amendment problems. Its decision is supported neither by precedent nor even by a fair application of the “balancing test” it proclaims in this very opinion.

I

Three basic principles underly this Court’s Fourth Amendment jurisprudence. First, warrantless searches are per se unreasonable, subject only to a few specifically delineated and well-recognized exceptions. See, e. g., Katz v. United States, 389 U. S. 347, 357 (1967); accord, Welsh v. Wisconsin, 466 U. S. 740, 748-749 (1984); United States v. Place, 462 U. S. 696, 701 (1983); Steagald v. United States, 451 U. S. 204, 211-212 (1981); Mincey v. Arizona, 437 U. S. 385 (1978); Terry v. Ohio, 392 U. S. 1, 20 (1968); Johnson v. United States, 333 U. S. 10, 13-14 (1948). Second, full-scale searches — whether conducted in accordance with the war*355rant requirement or pursuant to one of its exceptions — are “reasonable” in Fourth Amendment terms only on a showing of probable cause to believe that a crime has been committed and that evidence of the crime will be found in the place to be searched. Beck v. Ohio, 379 U. S. 89, 91 (1964); Wong Sun v. United States, 371 U. S. 471, 479 (1963); Brinegar v. United States, 338 U. S. 160, 175-176 (1949). Third, categories of intrusions that are substantially less intrusive than full-scale searches or seizures may be justifiable in accordance with a balancing test even absent a warrant or probable cause, provided that the balancing test used gives sufficient weight to the privacy interests that will be infringed. Dunaway v. New York, 442 U. S. 200, 210 (1979); Terry v. Ohio, supra.

Assistant Vice Principal Choplick’s thorough excavation of T. L. O.’s purse was undoubtedly a serious intrusion on her privacy. Unlike the searches in Terry v. Ohio, supra, or Adams v. Williams, 407 U. S. 143 (1972), the search at issue here encompassed a detailed and minute examination of respondent’s pocketbook, in which the contents of private papers and letters were thoroughly scrutinized.1 Wisely, neither petitioner nor the Court today attempts to justify the search of T. L. O.’s pocketbook as a minimally intrusive search in the Terry line. To be faithful to the Court’s settled doctrine, the inquiry therefore must focus on the warrant and probable-cause requirements.

A

I agree that schoolteachers or principals, when not acting as agents of law enforcement authorities, generally may conduct a search of their students’ belongings without first *356obtaining a warrant. To agree with the Court on this point is to say that school searches may justifiably be held to that extent to constitute an exception to the Fourth Amendment’s warrant requirement. Such an exception, however, is not to be justified, as the Court apparently holds, by assessing net social value through application of an unguided “balancing test” in which “the individual’s legitimate expectations of privacy and personal security” are weighed against “the government’s need for effective methods to deal with breaches of public order.” Ante, at 337. The Warrant Clause is something more than an exhortation to this Court to maximize social welfare as we see fit. It requires that the authorities must obtain a warrant before conducting a full-scale search. The undifferentiated governmental interest in law enforcement is insufficient to justify an exception to the warrant requirement. Rather, some special governmental interest beyond the need merely to apprehend lawbreakers is necessary to justify a categorical exception to the warrant requirement. For the most part, special governmental needs sufficient to override the warrant requirement flow from “exigency” — that is, from the press of time that makes obtaining a warrant either impossible or hopelessly infeasible. See United States v. Place, supra, at 701-702; Mincey v. Arizona, supra, at 393-394; Johnson v. United States, supra, at 15. Only after finding an extraordinary governmental interest of this kind do we — or ought we — engage in a balancing test to determine if a warrant should nonetheless be required.2

*357To require a showing of some extraordinary governmental interest before dispensing with the warrant requirement is not to undervalue society’s need to apprehend violators of the criminal law. To be sure, forcing law enforcement personnel to obtain a warrant before engaging in a search will predictably deter the police from conducting some searches that they would otherwise like to conduct. But this is not an unintended result of the Fourth Amendment’s protection of privacy; rather, it is the very purpose for which the Amendment was thought necessary. Only where the governmental interests at stake exceed those implicated in any ordinary law enforcement context — that is, only where there is some extraordinary governmental interest involved — is it legitimate to engage in a balancing test to determine whether a warrant is indeed necessary.

In this case, such extraordinary governmental interests do exist and are sufficient to justify an exception to the warrant requirement. Students are necessarily confined for most of the schoolday in close proximity to each other and to the school staff. I agree with the Court that we can take judicial notice of the serious problems of drugs and violence that plague our schools. As Justice Blackmun notes, teachers must not merely “maintain an environment conducive to learning” among children who “are inclined to test the outer boundaries of acceptable conduct,” but must also “protect the very safety of students and school personnel.” Ante, at 352-353. A teacher or principal could neither carry out essential teaching functions nor adequately protect students’ safety if required to wait for a warrant before conducting a necessary search.

B

I emphatically disagree with the Court’s decision to east aside the constitutional probable-cause standard when assessing the constitutional validity of a schoolhouse search. The Court’s decision jettisons the probable-cause standard— the only standard that finds support in the text of the Fourth *358Amendment — on the basis of its Rohrschach-like “balancing test.” Use of such a “balancing test” to determine the standard for evaluating the validity of a full-scale search represents a sizable innovation in Fourth Amendment analysis. This innovation finds support neither in precedent nor policy and portends a dangerous weakening of the purpose of the Fourth Amendment to protect the privacy and security of our citizens. Moreover, even if this Court’s historic understanding of the Fourth Amendment were mistaken and a balancing test of some kind were appropriate, any such test that gave adequate weight to the privacy and security interests protected by the Fourth Amendment would not reach the preordained result the Court's conclusory analysis reaches today. Therefore, because I believe that the balancing test used by the Court today is flawed both in its inception and in its execution, I respectfully dissent.

1

An unbroken line of cases in this Court have held that probable cause is a prerequisite for a full-scale search. In Carroll v. United States, 267 U. S. 132, 149 (1925), the Court held that “[o]n reason and authority the true rule is that if the search and seizure . . . are made upon probable cause .. . the search and seizure are valid.” Under our past decisions probable cause — which exists where “the facts and circumstances within [the officials’] knowledge and of which they had reasonably trustworthy information [are] sufficient in themselves to warrant a man of reasonable caution in the belief” that a criminal offense had occurred and the evidence would be found in the suspected place, id., at 162 — is the constitutional minimum for justifying a full-scale search, regardless of whether it is conducted pursuant to a warrant or, as in Carroll, within one of the exceptions to the warrant requirement. Henry v. United States, 361 U. S. 98, 104 (1959) (Carroll “merely relaxed the requirements for a warrant on grounds of practicality,” but “did not dispense *359with the need for probable cause”); accord, Chambers v. Maroney, 399 U. S. 42, 51 (1970) (“In enforcing the Fourth Amendment’s prohibition against unreasonable searches and seizures, the Court has insisted upon probable cause as a minimum requirement for a reasonable search permitted by the Constitution”).3

Our holdings that probable cause is a prerequisite to a full-scale search are based on the relationship between the two Clauses of the Fourth Amendment. The first Clause (“The right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures, shall not be violated . . .”) states the purpose of the Amendment and its coverage. The second Clause (“. . . and no Warrants shall issue but upon probable cause . . .”) gives content to the word “unreasonable” in the first Clause. “For all but . . . narrowly defined intrusions, the requisite ‘balancing’ has been performed in centuries of precedent and is embodied in the principle that seizures are ‘reasonable’ only if supported by probable cause.” Dunaway v. New York, 442 U. S., at 214.

I therefore fully agree with the Court that “the underlying command of the Fourth Amendment is always that searches and seizures be reasonable.” Ante, at 337. But this “underlying command” is not directly interpreted in each category of cases by some amorphous “balancing test.” Rather, the provisions of the Warrant Clause — a warrant and probable cause — provide the yardstick against which official searches *360and seizures are to be measured. The Fourth Amendment neither requires nor authorizes the conceptual free-for-all that ensues when an unguided balancing test is used to assess specific categories of searches. If the search in question is more than a minimally intrusive Terry stop, the constitutional probable-cause standard determines its validity.

To be sure, the Court recognizes that probable cause “ordinarily” is required to justify a full-scale search and that the existence of probable cause “bears on” the validity of the search. Ante, at 340-341. Yet the Court fails to cite any case in which a full-scale intrusion upon privacy interests has been justified on less than probable cause. The line of cases begun by Terry v. Ohio, 392 U. S. 1 (1968), provides no support, for they applied a balancing test only in the context of minimally intrusive searches that served crucial law enforcement interests. The search in Terry itself, for instance, was a “limited search of the outer clothing.” Id., at 30. The type of border stop at issue in United States v. Brignoni-Ponce, 422 U. S. 873, 880 (1975), usually “consume[d] no more than a minute”; the Court explicitly noted that “any further detention . . . must be based on consent or probable cause.” Id., at 882. See also United States v. Hensley, ante, at 224 (momentary stop); United States v. Place, 462 U. S., at 706-707 (brief detention of luggage for canine “sniff”); Pennsylvania v. Mimms, 434 U. S. 106 (1977) (per curiam) (brief frisk after stop for traffic violation); United States v. Martinez-Fuerte, 428 U. S. 543, 560 (1976) (characterizing intrusion as “minimal”); Adams v. Williams, 407 U. S. 143 (1972) (stop and frisk). In short, all of these cases involved “‘seizures’ so substantially less intrusive than arrests that the general rule requiring probable cause to make Fourth Amendment ‘seizures’ reasonable could be replaced by a balancing test.” Dunaway, supra, at 210.

Nor do the “administrative search” cases provide any comfort for the Court. In Camara v. Municipal Court, 387 U. S. 523 (1967), the Court held that the probable-cause standard governed even administrative searches. Although *361the Camara Court recognized that probable-cause standards themselves may have to be somewhat modified to take into account the special nature of administrative searches, the Court did so only after noting that “because [housing code] inspections are neither personal in nature nor aimed at the discovery of evidence of crime, they involve a relatively limited invasion of the urban citizen’s privacy.” Id., at 537. Subsequent administrative search cases have similarly recognized that such searches intrude upon areas whose owners harbor a significantly decreased expectation of privacy, see, e. g., Donovan v. Dewey, 452 U. S. 594, 598-599 (1981), thus circumscribing the injury to Fourth Amendment interests caused by the search.

Considerations of the deepest significance for the freedom of our citizens counsel strict adherence to the principle that no search may be conducted where the official is not in possession of probable cause — that is, where the official does not know of “facts and circumstances [that] warrant a prudent man in believing that the offense has been committed.” Henry v. United States, 361 U. S., at 102; see also id., at 100-101 (discussing history of probable-cause standard). The Fourth Amendment was designed not merely to protect against official intrusions whose social utility was less as measured by some “balancing test” than its intrusion on individual privacy; it was designed in addition to grant the individual a zone of privacy whose protections could be breached only where the “reasonable” requirements of the probable-cause standard were met. Moved by whatever momentary evil has aroused their fears, officials — perhaps even supported by a majority of citizens — may be tempted to conduct searches that sacrifice the liberty of each citizen to assuage the perceived evil.4 But the Fourth Amendment *362rests on the principle that a true balance between the individual and society depends on the recognition of “the right to be let alone — the most comprehensive of rights and the right most valued by civilized men.” Olmstead v. United States, 277 U. S. 438, 478 (1928) (Brandéis, J., dissenting). That right protects the privacy and security of the individual unless the authorities can cross a specific threshold of need, designated by the term “probable cause.” I cannot agree with the Court’s assertions today that a “balancing test” can replace the constitutional threshold with one that is more convenient for those enforcing the laws but less protective of the citizens’ liberty; the Fourth Amendment’s protections should not be defaced by “a balancing process that overwhelms the individual’s protection against unwarranted official intrusion by a governmental interest said to justify the search and seizure.” United States v. Martinez-Fuerte, supra, at 570 (Brennan, J., dissenting).

2

I thus do not accept the majority’s premise that “[t]o hold that the Fourth Amendment applies to searches conducted by school authorities is only to begin the inquiry into the standards governing such searches.” Ante, at 337. For me, the finding that the Fourth Amendment applies, coupled with the observation that what is at issue is a full-scale search, is the end of the inquiry. But even if I believed that a “balancing test” appropriately replaces the judgment of the Framers of the Fourth Amendment, I would nonetheless object to the cursory and shortsighted “test” that the Court employs to justify its predictable weakening of Fourth Amendment protections. In particular, the test employed by the Court vastly overstates the social costs that a probable-cause standard entails and, though it plausibly articulates the serious privacy interests at stake, inexplicably fails to accord them adequate weight in striking the balance.

*363The Court begins to articulate its “balancing test” by-observing that “the government’s need for effective methods to deal with breaches of public order” is to be weighed on one side of the balance. Ibid. Of course, this is not correct. It is not the government’s need for effective enforcement methods that should weigh in the balance, for ordinary Fourth Amendment standards — including probable cause— may well permit methods for maintaining the public order that are perfectly effective. If that were the case, the governmental interest in having effective standards would carry no weight at all as a justification for departing from the probable-cause standard. Rather, it is the costs of applying probable cause as opposed to applying some lesser standard that should be weighed on the government’s side.5

In order to tote up the costs of applying the probable-cause standard, it is thus necessary first to take into account the nature and content of that standard, and the likelihood that it would hamper achievement of the goal — vital not just to “teachers and administrators,” see ante, at 339 — of maintaining an effective educational setting in the public schools. The seminal statement concerning the nature of the probable-cause standard is found in Carroll v. United States, 267 U. S. 132 (1925). Carroll held that law enforcement authorities have probable cause to search where “the facts and circumstances within their knowledge and of which they had reasonably trustworthy information [are] sufficient in themselves to *364warrant a man of reasonable caution in the belief” that a criminal offense had occurred. Id., at 162. In Brinegar v. United States, 338 U. S. 160 (1949), the Court amplified this requirement, holding that probable cause depends upon “the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.” Id., at 175.

Two Terms ago, in Illinois v. Gates, 462 U. S. 213 (1983), this Court expounded at some length its view of the probable-cause standard. Among the adjectives used to describe the standard were “practical,” “fluid,” “flexible,” “easily applied,” and “nontechnical.” See id., at 232, 236, 239. The probable-cause standard was to be seen as a “common-sense” test whose application depended on an evaluation of the “totality of the circumstances.” Id., at 238.

Ignoring what Gates took such great pains to emphasize, the Court today holds that a new “reasonableness” standard is appropriate because it “will spare teachers and school administrators the necessity of schooling themselves in the niceties of probable cause and permit them to regulate their conduct according to the dictates of reason and common sense.” Ante, at 343. I had never thought that our pre-Gates understanding of probable cause defied either reason or common sense. But after Gates, I would have thought that there could be no doubt that this “nontechnical,” “practical,” and “easily applied” concept was eminently serviceable in a context like a school, where teachers require the flexibility to respond quickly and decisively to emergencies.

A consideration of the likely operation of the probable-cause standard reinforces this conclusion. Discussing the issue of school searches, Professor LaFave has noted that the cases that have reached the appellate courts “strongly suggest that in most instances the evidence of wrongdoing prompting teachers or principals to conduct searches is sufficiently detailed and specific to meet the traditional probable cause test.” 3 W. LaFave, Search and Seizure § 10.11, *365pp. 459-460 (1978).6 The problems that have caused this Court difficulty in interpreting the probable-cause standard have largely involved informants, see, e. g., Illinois v. Gates, supra; Spinelli v. United States, 393 U. S. 410 (1969); Aguilar v. Texas, 378 U. S. 108 (1964); Draper v. United States, 358 U. S. 307 (1959). However, three factors make it likely that problems involving informants will not make it difficult for teachers and school administrators to make probable-cause decisions. This Court’s decision in Gates applying a “totality of the circumstances” test to determine whether an informant’s tip can constitute probable cause renders the test easy for teachers to apply. The fact that students and teachers interact daily in the school building makes it more likely that teachers will get to know students who supply information; the problem of informants who remain anonymous even to the teachers — and who are therefore unavailable for verification or further questioning — is unlikely to arise. Finally, teachers can observe the behavior of students under suspicion to corroborate any doubtful tips they do receive.

As compared with the relative ease with which teachers can apply the probable-cause standard, the amorphous “reasonableness under all the circumstances” standard freshly coined by the Court today will likely spawn increased litigation and greater uncertainty among teachers and administrators. Of course, as this Court should know, an essential purpose of developing and articulating legal norms is to enable individuals to conform their conduct to those norms. A school system conscientiously attempting to obey the Fourth Amendment’s dictates under a probable-cause standard could, for example, consult decisions and other legal materials and prepare a booklet expounding the rough outlines of the concept. Such a booklet could be distributed to *366teachers to provide them with guidance as to when a search may be lawfully conducted. I cannot but believe that the same school system faced with interpreting what is permitted under the Court’s new “reasonableness” standard would be hopelessly adrift as to when a search may be permissible. The sad result of this uncertainty may well be that some teachers will be reluctant to conduct searches that are fully permissible and even necessary under the constitutional probable-cause standard, while others may intrude arbitrarily and unjustifiably on the privacy of students.7

One further point should be taken into account when considering the desirability of replacing the constitutional probable-cause standard. The question facing the Court is not whether the probable-cause standard should be replaced by a test of “reasonableness under all the circumstances.” Rather, it is whether traditional Fourth Amendment standards should recede before the Court’s new standard. Thus, although the Court today paints with a broad brush and holds its undefined “reasonableness” standard applicable to all school searches, I would approach the question with considerably more reserve. I would not think it necessary to develop a single standard to govern all school searches, any more *367than traditional Fourth Amendment law applies even the probable-cause standard to all searches and seizures. For instance, just as police officers may conduct a brief stop and frisk on something less than probable cause, so too should teachers be permitted the same flexibility. A teacher or administrator who had reasonable suspicion that a student was carrying a gun would no doubt have authority under ordinary Fourth Amendment doctrine to conduct a limited search of the student to determine whether the threat was genuine. The “costs” of applying the traditional probable-cause standard must therefore be discounted by the fact that, where additional flexibility is necessary and where the intrusion is minor, traditional Fourth Amendment jurisprudence itself displaces probable cause when it determines the validity of a search.

A legitimate balancing test whose function was something more substantial than reaching a predetermined conclusion acceptable to this Court’s impressions of what authority teachers need would therefore reach rather a different result than that reached by the Court today. On one side of the balance would be the costs of applying traditional Fourth Amendment standards — the “practical” and “flexible” probable-cause standard where a full-scale intrusion is sought, a lesser standard in situations where the intrusion is much less severe and the need for greater authority compelling. Whatever costs were toted up on this side would have to be discounted by the costs of applying an unprecedented and ill-defined “reasonableness under all the circumstances” test that will leave teachers and administrators uncertain as to their authority and will encourage excessive fact-based litigation.

On the other side of the balance would be the serious privacy interests of the student, interests that the Court admirably articulates in its opinion, ante, at 337-339, but which the Court’s new ambiguous standard places in serious jeopardy. I have no doubt that a fair assessment of the two *368sides of the balance would necessarily reach the same conclusion that, as I have argued above, the Fourth Amendment’s language compels — that school searches like that conducted in this case are valid only if supported by probable cause.

I — { 1 — I

Applying the constitutional probable-cause standard to the facts of this case, I would find that Mr. Choplick’s search violated T. L. O.’s Fourth Amendment rights. After escorting T. L. O. into his private office, Mr. Choplick demanded to see her purse. He then opened the purse to find evidence of whether she had been smoking in the bathroom. When he opened the purse, he discovered the pack of cigarettes. At this point, his search for evidence of the smoking violation was complete.

Mr. Choplick then noticed, below the cigarettes, a pack of cigarette rolling papers. Believing that such papers were “associated,” see ante, at 328, with the use of marihuana, he proceeded to conduct a detailed examination of the contents of her purse, in which he found some marihuana, a pipe, some money, an index card, and some private letters indicating that T. L. O. had sold marihuana to other students. The State sought to introduce this latter material in evidence at a criminal proceeding, and the issue before the Court is whether it should have been suppressed.

On my view of the case, we need not decide whether the initial search conducted by Mr. Choplick — the search for evidence of the smoking violation that was completed when Mr. Choplick found the pack of cigarettes — was valid. For Mr. Choplick at that point did not have probable cause to continue to rummage through T. L. O.’s purse. Mr. Choplick’s suspicion of marihuana possession at this time was based solely on the presence of the package of cigarette papers. The mere presence without more of such a staple item of commerce is insufficient to warrant a person of reasonable caution in inferring both that T. L. O. had violated the law *369by possessing marihuana and that evidence of that violation would be found in her purse. Just as a police officer could not obtain a warrant to search a home based solely on his claim that he had seen a package of cigarette papers in that home, Mr. Choplick was not entitled to search possibly the most private possessions of T. L. O. based on the mere presence of a package of cigarette papers. Therefore, the fruits of this illegal search must be excluded and the judgment of the New Jersey Supreme Court affirmed.

h-H H — H

In the past several Terms, this Court has produced a succession of Fourth Amendment opinions in which “balancing tests” have been applied to resolve various questions concerning the proper scope of official searches. The Court has begun to apply a “balancing test” to determine whether a particular category of searches intrudes upon expectations of privacy that merit Fourth Amendment protection. See Hudson v. Palmer, 468 U. S. 517, 527 (1984) (“Determining whether an expectation of privacy is ‘legitimate’ or ‘reasonable’ necessarily entails a balancing of interests”). It applies a “balancing test” to determine whether a warrant is necessary to conduct a search. See ante, at 340; United States v. Martinez-Fuerte, 428 U. S., at 564-566. In today’s opinion, it employs a “balancing test” to determine what standard should govern the constitutionality of a given category of searches. See ante, at 340-341. Should a search turn out to be unreasonable after application of all of these “balancing tests,” the Court then applies an additional “balancing test” to decide whether the evidence resulting from the search must be excluded. See United States v. Leon, 468 U. S. 897 (1984).

All of these “balancing tests” amount to brief nods by the Court in the direction of a neutral utilitarian calculus while the Court in fact engages in an unanalyzed exercise of judicial will. Perhaps this doctrinally destructive nihilism is merely *370a convenient umbrella under which a majority that cannot agree on a genuine rationale can conceal its differences. Compare ante, p. 327 (White, J., delivering the opinion of the Court), with ante, p. 348 (Powell, J., joined by O’Connor, J., concurring), and ante, p. 351 (Blackmun, J., concurring in judgment). And it may be that the real force underlying today’s decision is the belief that the Court purports to reject — the belief that the unique role served by the schools justifies an exception to the Fourth Amendment on their behalf. If so, the methodology of today’s decision may turn out to have as little influence in future cases as will its result, and the Court’s departure from traditional Fourth Amendment doctrine will be confined to the schools.

On my view, the presence of the word “unreasonable” in the text of the Fourth Amendment does not grant a shifting majority of this Court the authority to answer all Fourth Amendment questions by consulting its momentary vision of the social good. Full-scale searches unaccompanied by probable cause violate the Fourth Amendment. I do not pretend that our traditional Fourth Amendment doctrine automatically answers all of the difficult legal questions that occasionally arise. I do contend, however, that this Court has an obligation to provide some coherent framework to resolve such questions on the basis of more than a conclusory recitation of the results of a “balancing test.” The Fourth Amendment itself supplies that framework and, because the Court today fails to heed its message, I must respectfully dissent.

Justice Stevens,

with whom Justice Marshall joins, and with whom Justice Brennan joins as to Part I,

concurring in part and dissenting in part.

Assistant Vice Principal Choplick searched T. L. O.’s purse for evidence that she was smoking in the girls’ restroom. Because T. L. O.’s suspected misconduct was not illegal and did not pose a serious threat to school discipline, the New Jersey Supreme Court held that Choplick’s search *371of her purse was an unreasonable invasion of her privacy and that the evidence which he seized could not be used against her in criminal proceedings. The New Jersey court’s holding was a careful response to the case it was required to decide.

The State of New Jersey sought review in this Court, first arguing that the exclusionary rule is wholly inapplicable to searches conducted by school officials, and then contending that the Fourth Amendment itself provides no protection at all to the student’s privacy. The Court has accepted neither of these frontal assaults on the Fourth Amendment. It has, however, seized upon this “no smoking” case to announce “the proper standard” that should govern searches by school officials who are confronted with disciplinary problems far more severe than smoking in the restroom. Although I join Part II of the Court’s opinion, I continue to believe that the Court has unnecessarily and inappropriately reached out to decide a constitutional question. See 468 U. S. 1214 (1984) (Stevens, J., dissenting from reargument order). More importantly, I fear that the concerns that motivated the Court’s activism have produced a holding that will permit school administrators to search students suspected of violating only the most trivial school regulations and guidelines for behavior.

I

The question the Court decides today — whether Mr. Chop-lick’s search of T. L. O.’s purse violated the Fourth Amendment — was not raised by the State’s petition for writ of certiorari. That petition only raised one question: “Whether the Fourth Amendment’s exclusionary rule applies to searches made by public school officials and teachers in school.”1 The State quite properly declined to submit the former question because “[it] did not wish to present what might appear to be solely a factual dispute to this Court.”2 *372Since this Court has twice had the threshold question argued, I believe that it should expressly consider the merits of the New Jersey Supreme Court’s ruling that the exclusionary rule applies.

The New Jersey Supreme Court’s holding on this question is plainly correct. As the state court noted, this case does not involve the use of evidence in a school disciplinary proceeding; the juvenile proceedings brought against T. L. O. involved a charge that would have been a criminal offense if committed by an adult.3 Accordingly, the exclusionary rule issue decided by that court and later presented to this Court concerned only the use in a criminal proceeding of evidence obtained in a search conducted by a public school administrator.

Having confined the issue to the law enforcement context, the New Jersey court then reasoned that this Court’s cases have made it quite clear that the exclusionary rule is equally applicable “whether the public official who illegally obtained the evidence was a municipal inspector, See v. Seattle 387 U. S. 541 [1967]; Camara [v. Municipal Court,] 387 U. S. 523 [1967]; a firefighter, Michigan v. Tyler, 436 U. S. 499, 506 [1978]; or a school administrator or law enforcement official.”4 It correctly concluded “that if an official search violates constitutional rights, the evidence is not admissible in criminal proceedings.”5

When a defendant in a criminal proceeding alleges that she was the victim of an illegal search by a school administrator, the application of the exclusionary rule is a simple corollary of the principle that “all evidence obtained by searches and seizures in violation of the Constitution is, by that same authority, inadmissible in a state court.” Mapp v. Ohio, 367 U. S. 643, 655 (1961). The practical basis for this principle is, in part, its deterrent effect, see id., at 656, and as a general *373matter it is tolerably clear to me, as it has been to the Court, that the existence of an exclusionary remedy does deter the authorities from violating the Fourth Amendment by sharply reducing their incentive to do so.6 In the case of evidence obtained in school searches, the “overall educative effect”7 of the exclusionary rule adds important symbolic force to this utilitarian judgment.

Justice Brandéis was both a great student and a great teacher. It was he who wrote:

“Our Government is the potent, the omnipresent teacher. For good or for ill, it teaches the whole people by its example. Crime is contagious. If the Government becomes a lawbreaker, it breeds contempt for. law; it invites every man to become a law unto himself; it invites anarchy.” Olmstead v. United States, 277 U. S. 438, 485 (1928) (dissenting opinion).

Those of us who revere the flag and the ideals for which it stands believe in the power of symbols. We cannot ignore that rules of law also have a symbolic power that may vastly exceed their utility.

Schools are places where we inculcate the values essential to the meaningful exercise of rights and responsibilities by a self-governing citizenry.8 If the Nation’s students can be convicted through the use of arbitrary methods destructive of personal liberty, they cannot help but feel that they have *374been dealt with unfairly.9 The application of the exclusionary rule in criminal proceedings arising from illegal school searches makes an important statement to young people that “our society attaches serious consequences to a violation of constitutional rights,”10 and that this is a principle of “liberty and justice for all.”11

Thus, the simple and correct answer to the question presented by the State’s petition for certiorari would have required affirmance of a state court’s judgment suppressing evidence. That result would have been dramatically out of character for a Court that not only grants prosecutors relief from suppression orders with distressing regularity,12 but *375also is prone to rely on grounds not advanced by the parties in order to protect evidence from exclusion.13 In characteristic disregard of the doctrine of judicial restraint, the Court avoided that result in this case by ordering reargument and directing the parties to address a constitutional question that the parties, with good reason, had not asked the Court to decide. Because judicial activism undermines the Court’s power to perform its central mission in a legitimate way, I dissented from the reargument order. See 468 U. S. 1214 (1984). I have not modified the views expressed in that dissent, but since the majority has brought the question before us, I shall explain why I believe the Court has misapplied the standard of reasonableness embodied in the Fourth Amendment.

HH H-t

The search of a young woman’s purse by a school administrator is a serious invasion of her legitimate expectations of privacy. A purse “is a common repository for one’s personal effects and therefore is inevitably associated with the expectation of privacy.” Arkansas v. Sanders, 442 U. S. 753, 762 (1979). Although such expectations must sometimes yield to the legitimate requirements of government, in assessing the constitutionality of a warrantless search, our decision must be guided by the language of the Fourth Amendment: “The right of the people to be secure in their persons, houses, *376papers and effects, against unreasonable searches and seizures, shall not be violated . . . In order to evaluate the reasonableness of such searches, “it is necessary ‘first to focus upon the governmental interest which allegedly justifies official intrusion upon the constitutionally protected interests of the private citizen/ for there is ‘no ready test for determining reasonableness other than by balancing the need to search [or seize] against the invasion which the search [or seizure] entails.’” Terry v. Ohio, 392 U. S. 1, 20-21 (1968) (quoting Camara v. Municipal Court, 387 U. S. 523, 528, 534-537, (1967)).14

The “limited search for weapons” in Terry was justified by the “immediate interest of the police officer in taking steps to assure himself that the person with whom he is dealing is not armed with a weapon that could unexpectedly and fatally be used against him.” 392 U. S., at 23, 25. When viewed from the institutional perspective, “the substantial need of teachers and administrators for freedom to maintain order in the schools,” ante, at 341 (majority opinion), is no less acute. Violent, unlawful, or seriously disruptive conduct is fundamentally inconsistent with the principal function of teaching institutions which is to educate young people and prepare them for citizenship.15 When such conduct occurs amidst a sizable group of impressionable young people, it creates an explosive atmosphere that requires a prompt and effective response.

Thus, warrantless searches of students by school administrators are reasonable when undertaken for those purposes. *377But the majority’s statement of the standard for evaluating the reasonableness of such searches is not suitably adapted to that end. The majority holds that “a search of a student by a teacher or other school official will be ‘justified at its inception’ when there are reasonable grounds for suspecting that the search will turn up evidence that the student has violated or is violating either the law or the rules of the school” Ante, at 341-342. This standard will permit teachers and school administrators to search students when they suspect that the search will reveal evidence of even the most trivial school regulation or precatory guideline for student behavior. The Court’s standard for deciding whether a search is justified “at its inception” treats all violations of the rules of the school as though they were fungible. For the Court, a search for curlers and sunglasses in order to enforce the school dress code16 is apparently just as important as a search for evidence of heroin addiction or violent gang activity.

The majority, however, does not contend that school administrators have a compelling need to search students in *378order.to achieve optimum enforcement of minor school regulations.17 To the contrary, when minor violations are involved, there is every indication that the informal school disciplinary process, with only minimum requirements of due process,18 can function effectively without the power to search for enough evidence to prove a criminal case. In arguing that teachers and school administrators need the power to search students based on a lessened standard, the United States as amicus curiae relies heavily on empirical evidence of a contemporary crisis of violence and unlawful behavior that is seriously undermining the process of education in American schools.19 A standard better attuned to this concern would permit teachers and school administrators to search a student when they have reason to believe that the search will uncover evidence that the student is violating the law or engaging in conduct that is seriously disruptive of school order, or the educational process.

This standard is properly directed at “[t]he sole justification for the [warrantless] search.”20 In addition, a standard *379that varies the extent of the permissible intrusion with the gravity of the suspected offense is also more consistent with common-law experience and this Court’s precedent. Criminal law has traditionally recognized a distinction between essentially regulatory offenses and serious violations of the peace, and graduated the response of the criminal justice system depending on the character of the violation.21 The application of a similar distinction in evaluating the reasonableness of warrantless searches and seizures “is not a novel idea.” Welsh v. Wisconsin, 466 U. S. 740, 750 (1984).22

In Welsh, police officers arrived at the scene of a traffic accident and obtained information indicating that the driver of the automobile involved was guilty of a first offense of *380driving while intoxicated — a civil violation with a maximum fine of $200. The driver had left the scene of the accident, and the officers followed the suspect to his home where they arrested him without a warrant. Absent exigent circumstances, the warrantless invasion of the home was a clear violation of Payton v. New York, 445 U. S. 573 (1980). In holding that the warrantless arrest for the “noncriminal, traffic offense” in Welsh was unconstitutional, the Court noted that “application of the exigent-circumstances exception in the context of a home entry should rarely be sanctioned when there is probable cause to believe that only a minor offense . . . has been committed.” 466 U. S., at 753.

. . . The logic of distinguishing between minor and serious offenses in evaluating the reasonableness of school searches is almost too clear for argument. In order to justify the serious intrusion on the persons and privacy of young people that New Jersey asks this Court to approve, the State must identify “some real immediate and serious consequences.” McDonald v. United States, 335 U. S. 451, 460 (1948) (Jackson, J., concurring, joined by Frankfurter, J.).23 While school administrators have entirely legitimate reasons for adopting school regulations and guidelines for student behavior, the authorization of searches to enforce them “displays a shocking lack of all sense of proportion.” Id., 459.24

*381The majority offers weak deference to these principles of balance and decency by announcing that school searches will only be reasonable in scope “when the measures adopted are reasonably related to the objectives of the search and not excessively intrusive in light of the age and sex of the student and the nature of the infraction” Ante, at 342 (emphasis added). The majority offers no explanation why a two-part standard is necessary to evaluate the reasonableness of the ordinary school search. Significantly, in the balance of its opinion the Court pretermits any discussion of the nature of T. L. O.’s infraction of the “no smoking” rule.

The “rider” to the Court’s standard for evaluating the reasonableness of the initial intrusion apparently is the Court’s perception that its standard is overly generous and does not, by itself, achieve a fair balance between the administrator’s right to search and the student’s reasonable expectations of privacy. The Court’s standard for evaluating the “scope” of reasonable school searches is obviously designed to prohibit physically intrusive searches of students by persons of the opposite sex for relatively minor offenses. The Court’s effort to establish a standard that is, at once, clear enough to allow searches to be upheld in nearly every case, and flexible enough to prohibit obviously unreasonable intrusions of young adults’ privacy only creates uncertainty in the extent of its resolve to prohibit the latter. Moreover, the majority’s application of its standard in this case — to permit a male administrator to rummage through the purse of a female high school student in order to obtain evidence that she was smok*382ing in a bathroom — raises grave doubts in my mind whether its effort will be effective.25 Unlike the Court, I believe the nature of the suspected infraction is a matter of first importance in deciding whether any invasion of privacy is permissible.

Ill

The Court embraces the standard applied by the New Jersey Supreme Court as equivalent to-its own, and then deprecates the state court’s application of the standard as reflecting “a somewhat crabbed notion of reasonableness.” Ante, at 343. There is no mystery, however, in the state court’s finding that the search in this case was unconstitutional; the decision below was not based on a manipulation of reasonable suspicion, but on the trivial character of the activity that promoted the official search. The New Jersey Supreme Court wrote:

“We are satisfied that when a school official has reasonable grounds to believe that a student possesses evidence of illegal activity or activity that would interfere with school discipline and order, the school official has the right to conduct a reasonable search for such evidence.

“In determining whether the school official has reasonable grounds, courts should consider The child’s age, history, and school record, the prevalence and seriousness of the problem in the school to which the search was *383directed, the exigency to make the search without delay, and the probative value and reliability of the information used as a justification for the search.’”26

The emphasized language in the state court’s opinion focuses on the character of the rule infraction that is to be the object of the search.

In the view of the state court, there is a quite obvious and material difference between a search for evidence relating to violent or disruptive activity, and a search for evidence of a smoking rule violation. This distinction does not imply that a no-smoking rule is a matter of minor importance. Rather, like a rule that prohibits a student from being tardy, its occasional violation in a context that poses no threat of disrupting school order and discipline offers no reason to believe that an immediate search is necessary to avoid unlawful conduct, violence, or a serious impairment of the educational process.

A correct understanding of the New Jersey court’s standard explains why that court concluded in T. L. O.’s case that “the assistant principal did not have reasonable grounds to believe that the student was concealing in her purse evidence of criminal activity or evidence of activity that would seriously interfere with school discipline or order.”27 The importance of the nature of the rule infraction to the New Jersey Supreme Court’s holding is evident from its brief explanation of the principal basis for its decision:

“A student has an expectation of privacy in the contents of her purse. Mere possession of cigarettes did not violate school rule or policy, since the school allowed smoking in designated areas. The contents of the handbag had no direct bearing on the infraction.

“The assistant principal’s desire, legal in itself, to gather evidence to impeach the student’s credibility at a *384hearing on the disciplinary infraction does not validate the search.”28

Like the New Jersey Supreme Court, I would view this case differently if the Assistant Vice Principal had reason to believe T. L. O.’s purse contained evidence of criminal activity, or of an activity that would seriously disrupt school discipline. There was, however, absolutely no basis for any such assumption — not even a “hunch.”

In this case, Mr. Choplick overreacted to what appeared to be nothing more than a minor infraction — a rule prohibiting smoking in the bathroom of the freshmen’s and sophomores’ building.29 It is, of course, true that he actually found evidence of serious wrongdoing by T. L. 0., but no one claims that the prior search may be justified by his unexpected discovery. As far as the smoking infraction is concerned, the search for cigarettes merely tended to corroborate a teacher’s eyewitness account of T. L. O.’s violation of a minor regulation designed to channel student smoking behavior into designated locations. Because this conduct was neither unlawful nor significantly disruptive of school order or the educational process, the invasion of privacy associated with the forcible opening of T. L. O.’s purse was entirely unjustified at its inception.

A review of the sampling of school search cases relied on by the Court demonstrates how different this case is from those *385in which there was indeed a valid justification for intruding on a student’s privacy. In most of them the student was suspected of a criminal violation;30 in the remainder either violence or substantial disruption of school order or the integrity of the academic process was at stake.31 New involved matters as trivial as the no-smoking rule violated by T. L. O.32 The rule the Court adopts today is so open-ended that it may make the Fourth Amendment virtually meaningless in the school context. Although I agree that school administrators must have broad latitude to maintain order and discipline in our classrooms, that authority is not unlimited.

> I — I

The schoolroom is the first opportunity most citizens have to experience the power of government. Through it passes every citizen and public official, from schoolteachers to *386policemen and prison guards. The values they learn there, they take with them in life. One of our most cherished ideals is the one contained in the Fourth Amendment: that the government may not intrude on the personal privacy of its citizens without a warrant or compelling circumstance. The Court’s decision today is a curious moral for the Nation’s youth. Although the search of T. L. O.’s purse does not trouble today’s majority, I submit that we are not dealing with “matters relatively trivial to the welfare of the Nation. There are village tyrants as well as village Hampdens, but none who acts under color of law is beyond reach of the Constitution.” West Virginia State Board of Education v. Barnette, 319 U. S. 624, 638 (1943).

I respectfully dissent.

Justice Scalia

delivered the opinion of the Court.

The Student Athlete Drug Policy adopted by School District 47J in the town of Vernonia, Oregon, authorizes random urinalysis drug testing of students who participate in the District’s school athletics programs. We granted certiorari to decide whether this violates the Fourth and Fourteenth Amendments to the United States Constitution.

I

A

Petitioner Vernonia School District 47J (District) operates one high school and three grade schools in the logging community of Vernonia, Oregon. As elsewhere in small-town America, school sports play a prominent role in the town’s life, and student athletes are admired in their schools and in the community.

Drugs had not been a major problem in Vernonia schools. In the mid-to-late 1980’s, however, teachers and administrators observed a sharp increase in drug use. Students began to speak out about their attraction to the drug culture, and to boast that there was nothing the school could do about it. Along with more drugs came more disciplinary problems. *649Between 1988 and 1989 the number of disciplinary referrals in Vernonia schools rose to more than twice the number reported in the early 1980’s, and several students were suspended. Students became increasingly rude during class; outbursts of profane language became common.

Not only were student athletes included among the drug users but, as the District Court found, athletes were the leaders of the drug culture. 796 F. Supp. 1354, 1357 (Ore. 1992). This caused the District’s administrators particular concern, since drug use increases the risk of sports-related injury. Expert testimony at the trial confirmed the deleterious effects of drugs on motivation, memory, judgment, reaction, coordination, and performance. The high school football and wrestling coach witnessed a severe sternum injury suffered by a wrestler, and various omissions of safety procedures and misexecutions by football players, all attributable in his belief to the effects of drug use.

Initially, the District responded to the drug problem by offering special classes, speakers, and presentations designed to deter drug use. It even brought in a specially trained dog to detect drugs, but the drug problem persisted. According to the District Court:

“[T]he administration was at its wits end and ... a large segment of the student body, particularly those involved in interscholastic athletics, was in a state of rebellion. Disciplinary actions had reached ‘epidemic proportions.’ The coincidence of an almost three-fold increase in classroom disruptions and disciplinary reports along with the staff’s direct observations of students using drugs or glamorizing drug and alcohol use led the administration to the inescapable conclusion that the rebellion was being fueled by alcohol and drug abuse as well as the student’s misperceptions about the drug culture.” Ibid.

At that point, District officials began considering a drug-testing program. They held a parent “input night” to dis*650cuss the proposed Student Athlete Drug Policy (Policy), and the parents in attendance gave their unanimous approval. The school board approved the Policy for implementation in the fall of 1989. Its expressed purpose is to prevent student athletes from using drugs, to protect their health and safety, and to provide drug users with assistance programs.

B

The Policy applies to all students participating in interscholastic athletics. Students wishing to play sports must sign a form consenting to the testing and must obtain the written consent of their parents. Athletes are tested at the beginning of the season for their sport. In addition, once each week of the season the names of the athletes are placed in a “pool” from which a student, with the supervision of two adults, blindly draws the names of 10% of the athletes for random testing. Those selected are notified and tested that same day, if possible.

The student to be tested completes a specimen control form which bears an assigned number. Prescription medications that the student is taking must be identified by providing a copy of the prescription or a doctor’s authorization. The student then enters an empty locker room accompanied by an adult monitor of the same sex. Each boy selected produces a sample at a urinal, remaining fully clothed with his back to the monitor, who stands approximately 12 to 15 feet behind the student. Monitors may (though do not always) watch the student while he produces the sample, and they listen for normal sounds of urination. Girls produce samples in an enclosed bathroom stall, so that they can be heard but not observed. After the sample is produced, it is given to the monitor, who checks it for temperature and tampering and then transfers it to a vial.

The samples are sent to an independent laboratory, which routinely tests them for amphetamines, cocaine, and marijuana. Other drugs, such as LSD, may be screened at the *651request of the District, but the identity of a particular student does not determine which drugs will be tested. The laboratory’s procedures are 99.94% accurate. The District follows strict procedures regarding the chain of custody and access to test results. The laboratory does not know the identity of the students whose samples it tests. It is authorized to mail written test reports only to the superintendent and to provide test results to District personnel by telephone only after the requesting official recites a code confirming his authority. Only the superintendent, principals, vice-principals, and athletic directors have access to test results, and the results are not kept for more than one year.

If a sample tests positive, a second test is administered as soon as possible to confirm the result. If the second test is negative, no further action is taken. If the second test is positive, the athlete’s parents are notified, and the school principal convenes a meeting with the student and his parents, at which the student is given the option of (1) participating for six weeks in an assistance program that includes weekly urinalysis, or (2) suffering suspension from athletics for the remainder of the current season and the next athletic season. The student is then retested prior to the start of the next athletic season for which he or she is eligible. The Policy states that a second offense results in automatic imposition of option (2); a third offense in suspension for the remainder of the current season and the next two athletic seasons.

C

In the fall of 1991, respondent James Acton, then a seventh grader, signed up to play football at one of the District’s grade schools. He was denied participation, however, because he and his parents refused to sign the testing consent forms. The Actons filed suit, seeking declaratory and in-junctive relief from enforcement of the Policy on the grounds that it violated the Fourth and Fourteenth Amendments to the United States Constitution and Article I, § 9, of the Ore*652gon Constitution. After a bench trial, the District Court entered an order denying the claims on the merits and dismissing the action. 796 F. Supp., at 1355. The United States Court of Appeals for the Ninth Circuit reversed, holding that the Policy violated both the Fourth and Fourteenth Amendments and Article I, § 9, of the Oregon Constitution. 23 F. 3d 1514 (1994). We granted certiorari. 513 U. S. 1013 (1994).

II

The Fourth Amendment to the United States Constitution provides that the Federal Government shall not violate “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures . . . .” We have held that the Fourteenth Amendment extends this constitutional guarantee to searches and seizures by state officers, Elkins v. United States, 364 U. S. 206, 213 (1960), including public school officials, New Jersey v. T L. O., 469 U. S. 325, 336-337 (1985). In Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 617 (1989), we held that state-compelled collection and testing of urine, such as that required by the Policy, constitutes a “search” subject to the demands of the Fourth Amendment. See also Treasury Employees v. Von Raab, 489 U. S. 656, 665 (1989).

As the text of the Fourth Amendment indicates, the ultimate measure of the constitutionality of a governmental search is “reasonableness.” At least in a case such as this, where there was no clear practice, either approving or disapproving the type of search at issue, at the time the constitutional provision was enacted,1 whether a particular search meets the reasonableness standard “ ‘is judged by balancing *653its intrusion on the individual’s Fourth Amendment interests against its promotion of legitimate governmental interests.’” Skinner, supra, at 619 (quoting Delaware v. Prouse, 440 U. S. 648, 654 (1979)). Where a search is undertaken by law enforcement officials to discover evidence of criminal wrongdoing, this Court has said that reasonableness generally requires the obtaining of a judicial warrant, Skinner, supra, at 619. Warrants cannot be issued, of course, without the showing of probable cause required by the Warrant Clause. But a warrant is not required to establish the reasonableness of all government searches; and when a warrant is not required (and the Warrant Clause therefore not applicable), probable cause is not invariably required either. A search unsupported by probable cause can be constitutional, we have said, “when special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.” Griffin v. Wisconsin, 488 U. S. 868, 873 (1987) (internal quotation marks omitted).

We have found such “special needs” to exist in the public school context. There, the warrant requirement “would unduly interfere with the maintenance of the swift and informal disciplinary procedures [that are] needed,” and “strict adherence to the requirement that searches be based on probable cause” would undercut “the substantial need of teachers and administrators for freedom to maintain order in the schools.” T L. O., 469 U. S., at 340, 341. The school search we approved in T L. 0., while not based on probable cause, was based on individualized suspicion of wrongdoing. As we explicitly acknowledged, however, “‘the Fourth Amendment imposes no irreducible requirement of such suspicion,’ ” id., at 342, n. 8 (quoting United States v. Martinez-Fuerte, 428 U. S. 543, 560-561 (1976)). We have upheld sus-picionless searches and seizures to conduct drug testing of railroad personnel involved in train accidents, see Skinner, supra; to conduct random drug testing of federal customs officers who carry arms or are involved in drug interdiction, *654see Von Raab, supra; and to maintain automobile checkpoints looking for illegal immigrants and contraband, Martinez-Fuerte, supra, and drunk drivers, Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990).

1 — 1 1 — 1

The first factor to be considered is the nature of the privacy interest upon which the search here at issue intrudes. The Fourth Amendment does not protect all subjective expectations of privacy, but only those that society recognizes as “legitimate.” T L. O., 469 U. S., at 338. What expectations are legitimate varies, of course, with context, id., at 337, depending, for example, upon whether the individual asserting the privacy interest is at home, at work, in a car, or in a public park. In addition, the legitimacy of certain privacy expectations vis-a-vis the State may depend upon the individual’s legal relationship with the State. For example, in Griffin, supra, we held that, although a “probationer’s home, like anyone else’s, is protected by the Fourth Amendment,” the supervisory relationship between probationer and State justifies “a degree of impingement upon [a probationer’s] privacy that would not be constitutional if applied to the public at large.” 483 U. S., at 873, 875. Central, in our view, to the present case is the fact that the subjects of the Policy are (1) children, who (2) have been committed to the temporary custody of the State as schoolmaster.

Traditionally at common law, and still today, unemanci-pated minors lack some of the most fundamental rights of self-determination — including even the right of liberty in its narrow sense, i. e., the right to come and go at will. They are subject, even as to their physical freedom, to the control of their parents or guardians. See 59 Am. Jur. 2d, Parent and Child §10 (1987). When parents place minor children in private schools for their education, the teachers and administrators of those schools stand in loco parentis over the children entrusted to them. In fact, the tutor or schoolmas*655ter is the very prototype of that status. As Blackstone describes it, a parent “may . . . delegate part of his parental authority, during his life, to the tutor or schoolmaster of his child; who is then in loco parentis, and has such a portion of the power of the parent committed to his charge, viz. that of restraint and correction, as may be necessary to answer the purposes for which he is employed.” 1 W. Blackstone, Commentaries on the Laws of England 441 (1769).

In I L. O. we rejected the notion that public schools, like private schools, exercise only parental power over their students, which of course is not subject to constitutional constraints. 469 U. S., at 336. Such a view of things, we said, “is not entirely ‘consonant with compulsory education laws/ ” ibid. (quoting Ingraham v. Wright, 430 U. S. 651, 662 (1977)), and is inconsistent with our prior decisions treating school officials as state actors for purposes of the Due Process and Free Speech Clauses, T L. O., supra, at 336. But while denying that the State’s power over schoolchildren is formally no more than the delegated power of their parents, T. L. O. did not deny, but indeed emphasized, that the nature of that power is custodial and tutelary, permitting a degree of supervision and control that could not be exercised over free adults. “[A] proper educational environment requires close supervision of schoolchildren, as well as the enforcement of rules against conduct that would be perfectly permissible if undertaken by an adult.” 469 U. S., at 339. While we do not, of course, suggest that public schools as a general matter have such a degree of control over children as to give rise to a constitutional “duty to protect,” see DeShaney v. Winnebago County Dept. of Social Servs., 489 U. S. 189, 200 (1989), we have acknowledged that for many purposes “school authorities ac[t] in loco parentis,” Bethel School Dist. No. 403 v. Fraser, 478 U. S. 675, 684 (1986), with the power and indeed the duty to “inculcate the habits and manners of civility,” id., at 681 (internal quotation marks omitted). Thus, while children assuredly do not “shed their constitutional *656rights ... at the schoolhouse gate,” Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 506 (1969), the nature of those rights is what is appropriate for children in school. See, e. g., Goss v. Lopez, 419 U. S. 565, 581-582 (1975) (due process for a student challenging disciplinary suspension requires only that the teacher “informally discuss the alleged misconduct with the student minutes after it has occurred”); Fraser, supra, at 683 (“[I]t is a highly appropriate function of public school education to prohibit the use of vulgar and offensive terms in public discourse”); Hazelwood School Dist. v. Kuhlmeier, 484 U. S. 260, 273 (1988) (public school authorities may censor school-sponsored publications, so long as the censorship is “reasonably related to legitimate pedagogical concerns”); Ingraham, supra, at 682 (“Imposing additional administrative safeguards [upon corporal punishment]... would ... entail a significant intrusion into an area of primary educational responsibility”).

Fourth Amendment rights, no less than First and Fourteenth Amendment rights, are different in public schools than elsewhere; the “reasonableness” inquiry cannot disregard the schools’ custodial and tutelary responsibility for children. For their own good and that of their classmates, public school children are routinely required to submit to various physical examinations, and to be vaccinated against various diseases. According to the American Academy of Pediatrics, most public schools “provide vision and hearing screening and dental and dermatological checks. . . . Others also mandate scoliosis screening at appropriate grade levels.” Committee on School Health, American Academy of Pediatrics, School Health: A Guide for Health Professionals 2 (1987). In the 1991-1992 school year, all 50 States required public school students to be vaccinated against diphtheria, measles, rubella, and polio. U. S. Dept, of Health & Human Services, Public Health Service, Centers for Disease Control, State Immunization Requirements 1991-1992, p. 1. Particularly with regard to medical examinations and proce*657dures, therefore, “students within the school environment have a lesser expectation of privacy than members of the population generally.” I L. O., supra, at 348 (Powell, J., concurring).

Legitimate privacy expectations are even less with regard to student athletes. School sports are not for the bashful. They require “suiting up” before each practice or event, and showering and changing afterwards. Public school locker rooms, the usual sites for these activities, are not notable for the privacy they afford. The locker rooms in Vernonia are typical: No individual dressing rooms are provided; shower heads are lined up along a wall, unseparated by any sort of partition or curtain; not even all the toilet stalls have doors. As the United States Court of Appeals for the Seventh Circuit has noted, there is “an element of ‘communal undress’ inherent in athletic participation,” Schaill by Kross v. Tippecanoe County School Corp., 864 F. 2d 1309, 1318 (1988).

There is an additional respect in which school athletes have a reduced expectation of privacy. By choosing to “go out for the team,” they voluntarily subject themselves to a degree of regulation even higher than that imposed on students generally. In Vernonia’s public schools, they must submit to a preseason physical exam (James testified that his included the giving of a urine sample, App. 17), they must acquire adequate insurance coverage or sign an insurance waiver, maintain a minimum grade point average, and comply with any “rules of conduct, dress, training hours and related matters as may be established for each sport by the head coach and athletic director with the principal’s approval.” Record, Exh. 2, p. 30, ¶ 8. Somewhat like adults who choose to participate in a “closely regulated industry,” students who voluntarily participate in school athletics have reason to expect intrusions upon normal rights and privileges, including privacy. See Skinner, 489 U. S., at 627; United States v. Biswell, 406 U. S. 311, 316 (1972).

*658 >

Having considered the scope of the legitimate expectation of privacy at issue here, we turn next to the character of the intrusion that is complained of. We recognized in Skinner that collecting the samples for urinalysis intrudes upon “an excretory function traditionally shielded by great privacy.” 489 U. S., at 626. We noted, however, that the degree of intrusion depends upon the manner in which production of the urine sample is monitored. Ibid. Under the District’s Policy, male students produce samples at a urinal along a wall. They remain fully clothed and are only observed from behind, if at all. Female students produce samples in an enclosed stall, with a female monitor standing outside listening only for sounds of tampering. These conditions are nearly identical to those typically encountered in public restrooms, which men, women, and especially schoolchildren use daily. Under such conditions, the privacy interests compromised by the process of obtaining the urine sample are in our view negligible.

The other privacy-invasive aspect of urinalysis is, of course, the information it discloses concerning the state of the subject’s body, and the materials he has ingested. In this regard it is significant that the tests at issue here look only for drugs, and not for whether the student is, for example, epileptic, pregnant, or diabetic. See id., at 617. Moreover, the drugs for which the samples are screened are standard, and do not vary according to the identity of the student. And finally, the results of the tests are disclosed only to a limited class of school personnel who have a need to know; and they are not turned over to law enforcement authorities or used for any internal disciplinary function. 796 F. Supp., at 1364; see also 23 F. 3d, at 1521.2

*659Respondents argue, however, that the District’s Policy is in fact more intrusive than this suggests, because it requires the students, if they are to avoid sanctions for a falsely positive test, to identify in advance prescription medications they are taking. We agree that this raises some cause for concern. In Von Raab, we flagged as one of the salutary features of the Customs Service drug-testing program the fact that employees were not required to disclose medical information unless they tested positive, and, even then, the information was supplied to a licensed physician rather than to the Government employer. See Von Raab, 489 U. S., at 672-673, n. 2. On the other hand, we have never indicated that requiring advance disclosure of medications is per se unreasonable. Indeed, in Skinner we held that it was not “a significant invasion of privacy.” 489 U. S., at 626, n. 7. It can be argued that, in Skinner, the disclosure went only to the medical personnel taking the sample, and the Government personnel analyzing it, see id., at 609, but see id., at 610 (railroad personnel responsible for forwarding the sample, and presumably accompanying information, to the Government’s testing lab); and that disclosure to teachers and coaches — to persons who personally know the student — is a greater invasion of privacy. Assuming for the sake of argu*660ment that both those propositions are true, we do not believe they establish a difference that respondents are entitled to rely on here.

The General Authorization Form that respondents refused to sign, which refusal was the basis for James’s exclusion from the sports program, said only (in relevant part): “I . . . authorize the Vernonia School District to conduct a test on a urine specimen which I provide to test for drugs and/or alcohol use. I also authorize the release of information concerning the results of such a test to the Vernonia School District and to the parents and/or guardians of the student.” App. 10-11. While the practice of the District seems to have been to have a school official take medication information from the student at the time of the test, see id., at 29, 42, that practice is not set forth in, or required by, the Policy, which says simply: “Student athletes who . . . are or have been taking prescription medication must provide verification (either by a copy of the prescription or by doctor’s authorization) prior to being tested.” Id., at 8. It may well be that, if and when James was selected for random testing at a time that he was taking medication, the School District would have permitted him to provide the requested information in a confidential manner — for example, in a sealed envelope delivered to the testing lab. Nothing in the Policy contradicts that, and when respondents choose, in effect, to challenge the Policy on its face, we will not assume the worst. Accordingly, we reach the same conclusion as in Skinner: that the invasion of privacy was not significant.

V

Finally, we turn to consider the nature and immediacy of the governmental concern at issue here, and the efficacy of this means for meeting it. In both Skinner and Von Raab, we characterized the government interest motivating the search as “compelling.” Skinner, supra, at 628 (interest in preventing railway accidents); Von Raab, supra, at 670 (in*661terest in ensuring fitness of customs officials to interdict drugs and handle firearms). Relying on these cases, the District Court held that because the District’s program also called for drug testing in the absence of individualized suspicion, the District “must demonstrate a ‘compelling need’ for the program.” 796 F. Supp., at 1368. The Court of Appeals appears to have agreed with this view. See 23 F. 3d, at 1526. It is a mistake, however, to think that the phrase “compelling state interest,” in the Fourth Amendment context, describes a fixed, minimum quantum of governmental concern, so that one can dispose of a case by answering in isolation the question: Is there a compelling state interest here? Rather, the phrase describes an interest that appears important enough to justify the particular search at hand, in light of other factors that show the search to be relatively intrusive upon a genuine expectation of privacy. Whether that relatively high degree of government concern is necessary in this case or not, we think it is met.

That the nature of the concern is important — indeed, perhaps compelling — can hardly be doubted. Deterring drug use by our Nation’s schoolchildren is at least as important as enhancing efficient enforcement of the Nation’s laws against the importation of drugs, which was the governmental concern in Von Raab, supra, at 668, or deterring drug use by engineers and trainmen, which was the governmental concern in Skinner, supra, at 628. School years are the time when the physical, psychological, and addictive effects of drugs are most severe. “Maturing nervous systems are more critically impaired by intoxicants than mature ones are; childhood losses in learning are lifelong and profound”; “children grow chemically dependent more quickly than adults, and their record of recovery is depressingly poor.” Hawley, The Bumpy Road to Drug-Free Schools, 72 Phi Delta Kap-pan 310, 314 (1990). See also Estroff, Schwartz, & Hoff-mann, Adolescent Cocaine Abuse: Addictive Potential, Behavioral and Psychiatric Effects, 28 Clinical Pediatrics 550 *662(Dec. 1989); Kandel, Davies, Karus, & Yamaguchi, The Consequences in Young Adulthood of Adolescent Drug Involvement, 43 Arch. Gen. Psychiatry 746 (Aug. 1986). And of course the effects of a drug-infested school are visited not just upon the users, but upon the entire student body and faculty, as the educational process is disrupted. In the present case, moreover, the necessity for the State to act is magnified by the fact that this evil is being visited not just upon individuals at large, but upon children for whom it has undertaken a special responsibility of care and direction. Finally, it must not be lost sight of that this program is directed more narrowly to drug use by school athletes, where the risk of immediate physical harm to the drug user or those with whom he is playing his sport is particularly high. Apart from psychological effects, which include impairment of judgment, slow reaction time, and a lessening of the perception of pain, the particular drugs screened by the District’s Policy have been demonstrated to pose substantial physical risks to athletes. Amphetamines produce an “artificially induced heart rate increase, [peripheral vasoconstriction, [b]lood pressure increase, and [mjasking of the normal fatigue response,” making them a “very dangerous drug when used during exercise of any type.” Hawkins, Drugs and Other Ingesta: Effects on Athletic Performance, in H. Appenzeller, Managing Sports and Risk Management Strategies 90, 90-91 (1993). Marijuana causes “[ijrregular blood pressure responses during changes in body position,” “[Reduction in the oxygen-carrying capacity of the blood,” and “[ijnhibition of the normal sweating responses resulting in increased body temperature.” Id., at 94. Cocaine produces “[vjasocon-striction[,] [e]levated blood pressure,” and “[possible coronary artery spasms and myocardial infarction.” Ibid.

As for the immediacy of the District’s concerns: We are not inclined to question — indeed, we could not possibly find clearly erroneous — the District Court’s conclusion that “a large segment of the student body, particularly those in*663volved in interscholastic athletics, was in a state of rebellion,” that “[disciplinary actions had reached ‘epidemic proportions/” and that “the rebellion was being fueled by alcohol and drug abuse as well as by the student’s mispercep-tions about the drug culture.” 796 F. Supp., at 1357. That is an immediate crisis of greater proportions than existed in Skinner, where we upheld the Government’s drug-testing program based on findings of drug use by railroad employees nationwide, without proof that a problem existed on the particular railroads whose employees were subject to the test. See Skinner, 489 U. S., at 607. And of much greater proportions than existed in Von Raab, where there was no documented history of drug use by any customs officials. See Von Raab, 489 U. S., at 673; id., at 683 (Scalia, J., dissenting).

As to the efficacy of this means for addressing the problem: It seems to us self-evident that a drug problem largely fueled by the “role model” effect of athletes’ drug use, and of particular danger to athletes, is effectively addressed by making sure that athletes do not use drugs. Respondents argue that a “less intrusive means to the same end” was available, namely, “drug testing on suspicion of drug use.” Brief for Respondents 45-46. We have repeatedly refused to declare that only the “least intrusive” search practicable can be reasonable under the Fourth Amendment. Skinner, supra, at 629, n. 9 (collecting cases). Respondents’ alternative entails substantial difficulties — if it is indeed practicable at all. It may be impracticable, for one thing, simply because the parents who are willing to accept random drug testing for athletes are not willing to accept accusatory drug testing for all students, which transforms the process into a badge of shame. Respondents’ proposal brings the risk that teachers will impose testing arbitrarily upon troublesome but not drug-likely students. It generates the expense of defending lawsuits that charge such arbitrary imposition, or that simply demand greater process before accusatory drug

*664testing is imposed. And not least of all, it adds to the ever-expanding diversionary duties of schoolteachers the new function of spotting and bringing to account drug abuse, a task for which they are ill prepared, and which is not readily compatible with their vocation. Cf. Skinner, supra, at 628 (quoting 50 Fed. Reg. 31526 (1985)) (a drug impaired individual “will seldom display any outward ‘signs detectable by the lay person or, in many cases, even the physician’”); Goss, 419 U. S., at 594 (Powell, J., dissenting) (“There is an ongoing relationship, one in which the teacher must occupy many roles — educator, adviser, friend, and, at times, parent-substitute. It is rarely adversary in nature . . .”) (footnote omitted). In many respects, we think, testing based on “suspicion” of drug use would not be better, but worse.3

>

Taking into account all the factors we have considered above — the decreased expectation of privacy, the relative unobtrusiveness of the search, and the severity of the need met *665by the search — we conclude Vernonia’s Policy is reasonable and hence constitutional.

We caution against the assumption that suspicionless drug testing will readily pass constitutional muster in other contexts. The most significant element in this case is the first we discussed: that the Policy was undertaken in furtherance of the government’s responsibilities, under a public school system, as guardian and tutor of children entrusted to its care.4 Just as when the government conducts a search in its capacity as employer (a warrantless search of an absent employee’s desk to obtain an urgently needed file, for example), the relevant question is whether that intrusion upon privacy is one that a reasonable employer might engage in, see O’Connor v. Ortega, 480 U. S. 709 (1987); so also when the government acts as guardian and tutor the relevant question is whether the search is one that a reasonable guardian and tutor might undertake. Given the findings of need made by the District Court, we conclude that in the present case it is.

We may note that the primary guardians of Vernonia’s schoolchildren appear to agree. The record shows no objection to this districtwide program by any parents other than the couple before us here — even though, as we have described, a public meeting was held to obtain parents’ views. We find insufficient basis to contradict the judgment of Ver-nonia’s parents, its school board, and the District Court, as to what was reasonably in the interest of these children under the circumstances.

*666* * *

The Ninth Circuit held that Vernonia’s Policy not only violated the Fourth Amendment, but also, by reason of that violation, contravened Article I, § 9, of the Oregon Constitution. Our conclusion that the former holding was in error means that the latter holding rested on a flawed premise. We therefore vacate the judgment, and remand the case to the Court of Appeals for further proceedings consistent with this opinion.

It is so ordered.

Justice Ginsburg,

concurring.

The Court constantly observes that the School District’s drug-testing policy applies only to students who voluntarily participate in interscholastic athletics. Ante, at 650,657 (reduced privacy expectation and closer school regulation of student athletes), 662 (drug use by athletes risks immediate physical harm to users and those with whom they play). Correspondingly, the most severe sanction allowed under the District’s policy is suspension from extracurricular athletic programs. Ante, at 651. I comprehend the Court’s opinion as reserving the question whether the District, on no more than the showing made here, constitutionally could impose routine drug testing not only on those seeking to engage with others in team sports, but on all students required to attend school. Cf. United States v. Edwards, 498 F. 2d 496, 500 (CA2 1974) (Friendly, J.) (in contrast to search without notice and opportunity to avoid examination, airport search of passengers and luggage is avoidable “by choosing not to travel by air”) (internal quotation marks omitted).

Justice O’Connor,

with whom Justice Stevens and Justice Souter join,

dissenting.

The population of our Nation’s public schools, grades 7 through 12, numbers around 18 million. See U. S. Dept, of *667Education, National Center for Education Statistics, Digest of Education Statistics 58 (1994) (Table 43). By the reasoning of today’s decision, the millions of these students who participate in interscholastic sports, an overwhelming majority of whom have given school officials no reason whatsoever to suspect they use drugs at school, are open to an intrusive bodily search.

In justifying this result, the Court dispenses with a requirement of individualized suspicion on considered policy grounds. First, it explains that precisely because every student athlete is being tested, there is no concern that school officials might act arbitrarily in choosing whom to test. Second, a broad-based search regime, the Court reasons, dilutes the accusatory nature of the search. In making these policy arguments, of course, the Court sidesteps powerful, countervailing privacy concerns. Blanket searches, because they can involve “thousands or millions” of searches, “pos[e] a greater threat to liberty” than do suspicion-based ones, which “affec[t] one person at a time,” Illinois v. Krull, 480 U. S. 340, 365 (1987) (O’Connor, J., dissenting). Searches based on individualized suspicion also afford potential targets considerable control over whether they will, in fact, be searched because a person can avoid such a search by not acting in an objectively suspicious way. And given that the surest way to avoid acting suspiciously is to avoid the underlying wrongdoing, the costs of such a regime, one would think, are minimal.

But whether a blanket search is “better,” ante, at 664, than a regime based on individualized suspicion is not a debate in which we should engage. In my view, it is not open to judges or government officials to decide on policy grounds which is better and which is worse. For most of our constitutional history, mass, suspicionless searches have been generally considered per se unreasonable within the meaning of the Fourth Amendment. And we have allowed exceptions *668in recent years only where it has been clear that a suspicion-based regime would be ineffectual. Because that is not the case here, I dissent.

I

A

In Carroll v. United States, 267 U. S. 132 (1925), the Court explained that “[t]he Fourth Amendment does not denounce all searches or seizures, but only such as are unreasonable.” Id., at 147. Applying this standard, the Court first held that a search of a car was not unreasonable merely because it was warrantless; because obtaining a warrant is impractical for an easily movable object such as a car, the Court explained, a warrant is not required. The Court also held, however, that a warrantless car search was unreasonable unless supported by some level of individualized suspicion, namely, probable cause. Significantly, the Court did not base its conclusion on the express probable cause requirement contained in the Warrant Clause, which, as just noted, the Court found inapplicable. Rather, the Court rested its views on “what was deemed an unreasonable search and seizure when [the Fourth Amendment] was adopted” and “[what] will conserve public interests as well as the interests and rights of individual citizens.” Id., at 149. With respect to the “rights of individual citizens,” the Court eventually offered the simple yet powerful intuition that “those lawfully within the country, entitled to use the public highways, have a right to free passage without interruption or search unless there is known to a competent official authorized to search, probable cause for believing that their vehicles are carrying contraband or illegal merchandise.” Id., at 154.

More important for the purposes of this case, the Court clearly indicated that evenhanded treatment was no substitute for the individualized suspicion requirement:

“It would be intolerable and unreasonable if a prohibition agent were authorized to stop every automobile on *669the chance of finding liquor and thus subject all persons lawfully using the highways to the inconvenience and indignity of such a search.” Id., at 153-154.

The Carroll Court’s view that blanket searches are “intolerable and unreasonable” is well grounded in history. As recently confirmed in one of the most exhaustive analyses of the original meaning of the Fourth Amendment ever undertaken, see W. Cuddihy, The Fourth Amendment: Origins and Original Meaning (1990) (Ph.D. Dissertation at Claremont Graduate School) (hereinafter Cuddihy), what the Framers of the Fourth Amendment most strongly opposed, with limited exceptions wholly inapplicable here, were general searches — that is, searches by general warrant, by writ of assistance, by broad statute, or by any other similar authority. See id., at 1402, 1499, 1555; see also Clancy, The Role of Individualized Suspicion in Assessing the Reasonableness of Searches and Seizures, 25 Mem. St. U. L. Rev. 483, 528 (1994); Maclin, When the Cure for the Fourth Amendment Is Worse Than the Disease, 68 S. Cal. L. Rev. 1, 9-12 (1994); L. Levy, Original Intent and the Framers’ Constitution 221-246 (1988). Although, ironically, such warrants, writs, and statutes typically required individualized suspicion, see, e.g., Cuddihy 1140 (“Typical of the American warrants of 1761-76 was Starke’s ‘tobacco’ warrant, which commanded its bearer to ‘enter any suspected Houses’ ”) (emphasis added), such requirements were subjective and largely unenforceable. Accordingly, these various forms of authority led in practice to “virtually unrestrained,” and hence “general,” searches. J. Landynski, Search and Seizure and the Supreme Court 20 (1966). To be sure, the Fourth Amendment, in the Warrant Clause, prohibits by name only searches by general warrants. But that was only because the abuses of the general warrant were particularly vivid in the minds of the Framers’ generation, Cuddihy 1554-1560, and not because the Framers viewed other kinds of general searches as any less unreasonable. “Prohibition of the general warrant was part of a *670larger scheme to extinguish general searches categorically.” Id., at 1499.

More important, there is no indication in the historical materials that the Framers’ opposition to general searches stemmed solely from the fact that they allowed officials to single out individuals for arbitrary reasons, and thus that officials could render them reasonable simply by making sure to extend their search to every house in a given area or to every person in a given group. See Delaware v. Prouse, 440 U. S. 648, 664 (1979) (Rehnquist, J., dissenting) (referring to this as the “ ‘misery loves company’ ” theory of the Fourth Amendment). On the contrary, although general searches were typically arbitrary, they were not invariably so. Some general searches, for example, were of the arguably evenhanded “door-to-door” kind. Cuddihy 1091; see also id., at 377, 1502, 1557. Indeed, Cuddihy’s descriptions of a few blanket searches suggest they may have been considered more worrisome than the typical general search. See id., at 575 (“One type of warrant [between 1700 and 1760] went beyond a general search, in which the searcher entered and inspected suspicious places, by requiring him to search entire categories of places whether he suspected them or not”); id., at 478 (“During the exigencies of Queen Anne’s War, two colonies even authorized searches in 1706 that extended to entire geographic areas, not just to suspicious houses in a district, as conventional general warrants allowéd”).

Perhaps most telling of all, as reflected in the text of the Warrant Clause, the particular way the Framers chose to curb the abuses of general warrants — and by implication, all general searches — was not to impose a novel “evenhandedness” requirement; it was to retain the individualized suspicion requirement contained in the typical general warrant, but to make that requirement meaningful and enforceable, for instance, by raising the required level of individualized suspicion to objective probable cause. See U. S. Const., Arndt. 4. So, for example, when the same Congress that *671proposed the Fourth Amendment authorized duty collectors to search for concealed goods subject to import duties, specific warrants were required for searches on land; but even for searches at sea, where warrants were impractical and thus not required, Congress nonetheless limited officials to searching only those ships and vessels “in which [a collector] shall have reason to suspect any goods, wares or merchandise subject to duty shall be concealed.” The Collection Act of July 31, 1789, § 24, 1 Stat. 43 (emphasis added); see also Cuddihy 1490-1491 (“The Collection Act of 1789 was [the] most significant [of all early search statutes], for it identified the techniques of search and seizure that the framers of the amendment believed reasonable while they were framing it”). Not surprisingly, the Carroll Court relied on this statute and other subsequent ones like it in arriving at its views. See Carroll, 267 U. S., at 160-151, 154; cf. Clancy, supra, at 489 (“While the plain language of the Amendment does not mandate individualized suspicion as a necessary component of all searches and seizures, the historical record demonstrates that the framers believed that individualized suspicion was an inherent quality of reasonable searches and seizures”).

True, not all searches around the time the Fourth Amendment was adopted required individualized suspicion — although most did. A search incident to arrest was an obvious example of one that did not, see Cuddihy 1518, but even those searches shared the essential characteristics that distinguish suspicion-based searches from abusive general searches: they only “affec[t] one person at a time,” Krull, 480 U. S., at 365 (O’Connor, J., dissenting), and they are generally avoidable by refraining from wrongdoing. See supra, at 667. Protection of privacy, not evenhandedness, was then and is now the touchstone of the Fourth Amendment.

The view that mass, suspicionless searches, however evenhanded, are generally unreasonable remains inviolate in the criminal law enforcement context, see Ybarra v. Illinois, 444 *672U. S. 85 (1979) (invalidating evenhanded, nonaccusatory pat-down for weapons of all patrons in a tavern in which there was probable cause to think drug dealing was going on), at least where the search is more than minimally intrusive, see Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990) (upholding the brief and easily avoidable detention, for purposes of observing signs of intoxication, of all motorists approaching a roadblock). It is worth noting in this regard that state-compelled, state-monitored collection and testing of urine, while perhaps not the most intrusive of searches, see, e. g., Bell v. Wolfish, 441 U. S. 520, 558-560 (1979) (visual body cavity searches), is still “particularly destructive of privacy and offensive to personal dignity.” Treasury Employees v. Von Raab, 489 U. S. 656, 680 (1989) (Scalia, J., dissenting); see also ante, at 658; Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 617 (1989). We have not hesitated to treat monitored bowel movements as highly intrusive (even in the special border search context), compare United States v. Martinez-Fuerte, 428 U. S. 543 (1976) (brief interrogative stops of all motorists crossing certain border checkpoint reasonable without individualized suspicion), with United States v. Montoya de Hernandez, 473 U. S. 531 (1985) (monitored bowel movement of border crossers reasonable only upon reasonable suspicion of alimentary canal smuggling), and it is not easy to draw a distinction. See Fried, Privacy, 77 Yale L. J. 475, 487 (1968) (“[I]n our culture the excretory functions are shielded by more or less absolute privacy”). And certainly monitored urination combined with urine testing is more intrusive than some personal searches we have said trigger Fourth Amendment protections in the past. See, e. g., Cupp v. Murphy, 412 U. S. 291, 295 (1973) (Stewart, J.) (characterizing the scraping of dirt from under a person’s fingernails as a “ ‘severe, though brief, intrusion upon cherished personal security’ ”) (citation omitted). Finally, the collection and testing of urine is, of course, a search of a person, one of only four categories of suspect *673searches the Constitution mentions by name. See U. S. Const., Arndt. 4 (listing “persons, houses, papers, and effects”); cf. Cuddihy 835, 1518, 1552, n. 394 (indicating long history of outrage at personal searches before 1789).

Thus, it remains the law that the police cannot, say, subject to drug testing every person entering or leaving a certain drug-ridden neighborhood in order to find evidence of crime. 3 W. LaFave, Search and Seizure § 9.5(b), pp. 551-553 (2d ed. 1987) (hereinafter LaFave). And this is true even though it is hard to think of a more compelling government interest than the need to fight the scourge of drugs on our streets and in our neighborhoods. Nor could it be otherwise, for if being evenhanded were enough to justify evaluating a search regime under an open-ended balancing test, the Warrant Clause, which presupposes that there is some category of searches for which individualized suspicion is nonnegotiable, see 2 LaFave §4.1, at 118, would be a dead letter.

Outside the criminal context, however, in response to the exigencies of modern life, our cases have upheld several evenhanded blanket searches, including some that are more than minimally intrusive, after balancing the invasion of privacy against the government’s strong need. Most of these cases, of course, are distinguishable insofar as they involved searches either not of a personally intrusive nature, such as searches of closely regulated businesses, see, e. g., New York v. Burger, 482 U. S. 691, 699-703 (1987); cf. Cuddihy 1501 (“Even the states with the strongest constitutional restrictions on general searches had long exposed commercial establishments to warrantless inspection”), or arising in unique contexts such as prisons, see, e. g., Wolfish, supra, at 558-560 (visual body cavity searches of prisoners following contact visits); cf. Cuddihy 1516-1519, 1552-1553 (indicating that searches incident to arrest and prisoner searches were the only common personal searches at time of founding). This certainly explains why Justice Scalia, in his dissent in our recent Von Raab decision, found it significant that “[u]ntil *674today this Court had upheld a bodily search separate from arrest and without individualized suspicion of wrongdoing only with respect to prison inmates, relying upon the uniquely dangerous nature of that environment.” Von Raab, supra, at 680 (citation omitted).

In any event, in many of the cases that can be distinguished on the grounds suggested above and, more important, in all of the cases that cannot, see, e. g., Skinner, supra (blanket drug testing scheme); Von Raab, supra (same); cf. Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523 (1967) (area-wide searches of private residences), we upheld the suspicionless search only after first recognizing the Fourth Amendment’s longstanding preference for a suspicion-based search regime, and then pointing to sound reasons why such a regime would likely be ineffectual under the unusual circumstances presented. In Skinner, for example, we stated outright that “ ‘some quantum of individualized suspicion’ ” is “usually required” under the Fourth Amendment, Skinner, supra, at 624, quoting Martinez-Fuerte, supra, at 560, and we built the requirement into the test we announced: “In limited circumstances, where the privacy interests implicated by the search are minimal, and where an important governmental interest furthered by the intrusion would be placed in jeopardy by a requirement of individualized suspicion, a search may be reasonable despite the absence of such suspicion,” 489 U. S., at 624 (emphasis added). The obvious negative implication of this reasoning is that, if such an individualized suspicion requirement would not place the government’s objectives in jeopardy, the requirement should not be forsaken. See also Von Raab, supra, at 665-666.

Accordingly, we upheld the suspicionless regime at issue in Skinner on the firm understanding that a requirement of individualized suspicion for testing train operators for drug or alcohol impairment following serious train accidents would be unworkable because “the scene of a serious rail *675accident is chaotic.” Skinner, 489 U. S., at 631. (Of course, it could be plausibly argued that the fact that testing occurred only after train operators were involved in serious train accidents amounted to an individualized suspicion requirement in all but name, in light of the record evidence of a strong link between serious train accidents and drug and alcohol use.) We have performed a similar inquiry in the other cases as well. See Von Raab, 489 U. S., at 674 (suspicion requirement for searches of customs officials for drug impairment impractical because “not feasible to subject [such] employees and their work product to the kind of day-to-day scrutiny that is the norm in more traditional office environments”); Camara, supra, at 537 (suspicion requirement for searches of homes for safety code violations impractical because conditions such as “faulty wiring” not observable from outside of house); see also Wolfish, 441 U. S., at 559-560, n. 40 (suspicion requirement for searches of prisoners for smuggling following contact visits impractical because observation necessary to gain suspicion would cause “obvious disruption of the confidentiality and intimacy that these visits are intended to afford”); Martinez-Fuerte, 428 U. S., at 557 (“A requirement that stops on major routes inland always be based on reasonable suspicion would be impractical because the flow of traffic tends to be too heavy to allow the particularized study of a given car that would enable it to be identified as a possible carrier of illegal aliens”); United States v. Edwards, 498 F. 2d 496, 500 (CA2 1974) (Friendly, J.) (suspicion-based searches of airport passengers’ carry-on luggage impractical because of the great number of plane travelers and “conceded inapplicability” of the profile method of detecting hijackers).

Moreover, an individualized suspicion requirement was often impractical in these cases because they involved situations in which even one undetected instance of wrongdoing could have injurious consequences for a great number of people. See, e. g., Camara, supra, at 535 (even one safety code *676violation can cause “fires and epidemics [that] ravage large urban areas”); Skinner, supra, at 628 (even one drug- or alcohol-impaired train operator can lead to the “disastrous consequences” of a train wreck, such as “great human loss”); Von Raab, supra, at 670, 674, 677 (even one customs official caught up in drugs can, by virtue of impairment, susceptibility to bribes, or indifference, result in the noninterdiction of a “sizable drug shipmen[t],” which eventually injures the lives of thousands, or to a breach of “national security”); Edwards, supra, at 600 (even one hijacked airplane can destroy “ ‘hundreds of human lives and millions of dollars of property’ ”) (citation omitted).

B

The instant case stands in marked contrast. One searches today’s majority opinion in vain for recognition that history and precedent establish that individualized suspicion is “usually required” under the Fourth Amendment (regardless of whether a warrant and probable cause are also required) and that, in the area of intrusive personal searches, the only recognized exception is for situations in which a suspicion-based scheme would be likely ineffectual. See supra, at 674-675 and this page. Far from acknowledging anything special about individualized suspicion, the Court treats a suspicion-based regime as if it were just any run-of-the-mill, less intrusive alternative — that is, an alternative that officials may bypass if the lesser intrusion, in their reasonable estimation, is outweighed by policy concerns unrelated to practicability.

As an initial matter, I have serious doubts whether the Court is right that the District reasonably found that the lesser intrusion of a suspicion-based testing program outweighed its genuine concerns for the adversarial nature of such a program, and for its abuses. See ante, at 663-664. For one thing, there are significant safeguards against abuses. The fear that a suspicion-based regime will lead to the testing of “troublesome but not drug-likely” students, *677ante, at 663, for example, ignores that the required level of suspicion in the school context is objectively reasonable suspicion. In this respect, the facts of our decision in New Jersey v. I L. O., 469 U. S. 325 (1985), should be reassuring. There, we found reasonable suspicion to search a ninth-grade girl’s purse for cigarettes after a teacher caught the girl smoking in the bathroom with a companion who admitted it. See id., at 328, 345-346. Moreover, any distress arising from what turns out to be a false accusation can be minimized by keeping the entire process confidential.

For another thing, the District’s concern for the adversarial nature of a suspicion-based regime (which appears to extend even to those who are rightly accused) seems to ignore the fact that such a regime would not exist in a vacuum. Schools already have adversarial, disciplinary schemes that require teachers and administrators in many areas besides drug use to investigate student wrongdoing (often by means of accusatory searches); to make determinations about whether the wrongdoing occurred; and to impose punishment. To such a scheme, suspicion-based drug testing would be only a minor addition. The District’s own elaborate disciplinary scheme is reflected in its handbook, which, among other things, lists the following disciplinary “problem areas” carrying serious sanctions: “DEFIANCE OF AUTHORITY,” “DISORDERLY OR DISRUPTIVE CONDUCT INCLUDING FOUL LANGUAGE,” “AUTOMOBILE USE OR MISUSE,” “FORGERY OR LYING,” “GAMBLING,” “THEFT,” “TOBACCO,” “MISCHIEF,” “VANDALISM,” “RECKLESSLY ENDANGERING,” “MENACING OR HARASSMENT,” “ASSAULT,” “FIGHTING,” “WEAPONS,” “EXTORTION,” “EXPLOSIVE DEVICES,” and “ARSON.” Record, Exh. 2, p. 11; see also id., at 20-21 (listing rules regulating dress and grooming, public displays of affection, and the wearing of hats inside); cf. id., at 8 (“RESPONSIBILITIES OF SCHOOLS” include “To develop and distribute to parents and students reasonable rules *678and regulations governing student behavior and attendance” and “To provide fair and reasonable standards of conduct and to enforce those standards through appropriate disciplinary action”). The high number of disciplinary referrals in the record in this case illustrates the District’s robust scheme in action.

In addition to overstating its concerns with a suspicion-based program, the District seems to have understated the extent to which such a program is less intrusive of students’ privacy. By invading the privacy of a few students rather than many (nationwide, of thousands rather than millions), and by giving potential search targets substantial control over whether they will, in fact, be searched, a suspicion-based scheme is significantly less intrusive.

In any event, whether the Court is right that the District reasonably weighed the lesser intrusion of a suspicion-based scheme against its policy concerns is beside the point. As stated, a suspicion-based search regime is not just any less intrusive alternative; the individualized suspicion requirement has a legal pedigree as old as the Fourth Amendment itself, and it may not be easily cast aside in the name of policy concerns. It may only be forsaken, our cases in the personal search context have established, if a suspicion-based regime would likely be ineffectual.

But having misconstrued the fundamental role of the individualized suspicion requirement in Fourth Amendment analysis, the Court never seriously engages the practicality of such a requirement in the instant case. And that failure is crucial because nowhere is it less clear that an individualized suspicion requirement would be ineffectual than in the school context. In most schools, the entire pool of potential search targets — students—is under constant supervision by teachers and administrators and coaches, be it in classrooms, hallways, or locker rooms. See T. L. O., 469 U. S., at 339 (“[A] proper educational environment requires close supervision of schoolchildren”).

*679The record here indicates that the Vernonia schools are no exception. The great irony of this case is that most (though not all) of the evidence the District introduced to justify its suspicionless drug testing program consisted of first- or second-hand stories of particular, identifiable students acting in ways that plainly gave rise to reasonable suspicion of in-school drug use — and thus that would have justified a drug-related search under our T. L. O. decision. See id., at 340-342 (warrant and probable cause not required for school searches; reasonable suspicion sufficient). Small groups of students, for example, were observed by a teacher “passing joints back and forth” across the street at a restaurant before school and during school hours. Tr. 67 (Apr. 29,1992). Another group was caught skipping school and using drugs at one of the students’ houses. See id., at 93-94. Several students actually admitted their drug use to school officials (some of them being caught with marijuana pipes). See id., at 24. One student presented himself to his teacher as “clearly obviously inebriated” and had to be sent home. Jd., at 68. Still another was observed dancing and singing at the top of his voice in the back of the classroom; when the teacher asked what was going on, he replied, “Well, I’m just high on life.” Id., at 89-90. To take a final example, on a certain road trip, the school wrestling coach smelled marijuana smoke in a motel room occupied by four wrestlers, see id., at 110-112, an observation that (after some questioning) would probably have given him reasonable suspicion to test one or all of them. Cf. 4 LaFave § 10.11(b), at 169 (“[I]n most instances the evidence of wrongdoing prompting teachers or principals to conduct searches is sufficiently detailed and specific to meet the traditional probable cause test”).

In light of all this evidence of drug use by particular students, there is a substantial basis for concluding that a vigorous regime of suspicion-based testing (for which the District appears already to have rules in place, see Record, Exh. 2, at 14, 17) would have gone a long way toward solving Ver-*680nonia’s school drug problem while preserving the Fourth Amendment rights of James Acton and others like him. And were there any doubt about such a conclusion, it is removed by indications in the record that suspicion-based testing could have been supplemented by an equally vigorous campaign to have Vernonia’s parents encourage their children to submit to the District’s voluntary drug testing program. See id., at 32 (describing the voluntary program); ante, at 665 (noting widespread parental support for drug testing). In these circumstances, the Fourth Amendment dictates that a mass, suspicionless search regime is categorically unreasonable.

I recognize that a suspicion-based scheme, even where reasonably effective in controlling in-school drug use, may not be as effective as a mass, suspicionless testing regime. In one sense, that is obviously true — -just as it is obviously true that suspicion-based law enforcement is not as effective as mass, suspicionless enforcement might be. “But there is nothing new in the realization” that Fourth Amendment protections come with a price. Arizona v. Hicks, 480 U. S. 321, 329 (1987). Indeed, the price we pay is higher in the criminal context, given that police do not closely observe the entire class of potential search targets (all citizens in the area) and must ordinarily adhere to the rigid requirements of a warrant and probable cause.

The principal counterargument to all this, central to the Court’s opinion, is that the Fourth Amendment is more lenient with respect to school searches. That is no doubt correct, for, as the Court explains, ante, at 655-656, schools have traditionally had special guardianlike responsibilities for children that necessitate a degree of constitutional leeway. This principle explains the considerable Fourth Amendment leeway we gave school officials in I L. O. In that case, we held that children at school do not enjoy two of the Fourth Amendment's traditional categorical protections against unreasonable searches and seizures: the warrant requirement *681and the probable cause requirement. See T L. O., 469 U. S., at 337-343. And this was true even though the same children enjoy such protections “in a nonschool setting.” Id., at 348 (Powell, J., concurring).

The instant case, however, asks whether the Fourth Amendment is even more lenient than that, i. e., whether it is so lenient that students may be deprived of the Fourth Amendment’s only remaining, and most basic, categorical protection: its strong preference for an individualized suspicion requirement, with its accompanying antipathy toward personally intrusive, blanket searches of mostly innocent people. It is not at all clear that people in prison lack this categorical protection, see Wolfish, 441 U. S., at 558-560 (upholding certain suspicionless searches of prison inmates); but cf. supra, at 675 (indicating why suspicion requirement was impractical in Wolfisk), and we have said “[w]e are not yet ready to hold that the schools and the prisons need be equated for purposes of the Fourth Amendment.” T L. O., supra, at 338-339. Thus, if we are to mean what we often proclaim — that students do not “shed their constitutional rights ... at the schoolhouse gate,” Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 506 (1969) — the answer must plainly be no.1

*682For the contrary position, the Court relies on cases such as T L. O., Ingraham v. Wright, 430 U. S. 651 (1977), and Goss v. Lopez, 419 U. S. 565 (1975). See ante, at 655-656. But I find the Court’s reliance on these cases ironic. If anything, they affirm that schools have substantial constitutional leeway in carrying out their traditional mission of responding to particularized wrongdoing. See T. L. O., supra (leeway in investigating particularized wrongdoing); Ingraham, supra (leeway in punishing particularized wrongdoing); Goss, supra (leeway in choosing procedures by which particularized wrongdoing is punished).

By contrast, intrusive, blanket searches of schoolchildren, most of whom are innocent, for evidence of serious wrongdoing are not part of any traditional school function of which I am aware. Indeed, many schools, like many parents, prefer to trust their children unless given reason to do otherwise. As James Acton’s father said on the witness stand, “[suspi-cionless testing] sends a message to children that are trying to be responsible citizens . . . that they have to prove that they’re innocent..., and I think that kind of sets a bad tone for citizenship.” Tr. 9 (Apr. 29, 1992).

I find unpersuasive the Court’s reliance, ante, at 656-657, on the widespread practice of physical examinations and vaccinations, which are both blanket searches of a sort. Of course, for these practices to have any Fourth Amendment significance, the Court has to assume that these physical exams and vaccinations are typically “required” to a similar extent that urine testing and collection is required in the instant case, i. e., that they are required regardless of parental *683objection and that some meaningful sanction attaches to the failure to submit. In any event, without forming any particular view of such searches, it is worth noting that a suspicion requirement for vaccinations is not merely impractical; it is nonsensical, for vaccinations are not searches for anything in particular and so there is nothing about which to be suspicious. Nor is this saying anything new; it is the same theory on which, in part, we have repeatedly upheld certain inventory searches. See, e. g., South Dakota v. Opperman, 428 U. S. 364, 370, n. 5 (1976) (“The probable-cause approach is unhelpful when analysis centers upon the reasonableness of routine administrative caretaking functions”). As for physical examinations, the practicability of a suspicion requirement is highly doubtful because the conditions for which these physical exams ordinarily search, such as latent heart conditions, do not manifest themselves in observable behavior the way school drug use does. See supra, at 679-680.

It might also be noted that physical exams (and of course vaccinations) are not searches for conditions that reflect wrongdoing on the part of the student, and so are wholly nonaccusatory and have no consequences that can be regarded as punitive. These facts may explain the absence of Fourth Amendment challenges to such searches. By contrast, although I agree with the Court that the accusatory nature of the District’s testing program is diluted by making it a blanket one, any testing program that searches for conditions plainly reflecting serious wrongdoing can never be made wholly nonaccusatory from the student’s perspective, the motives for the program notwithstanding; and for the same reason, the substantial consequences that can flow from a positive test, such as suspension from sports, are invariably — and quite reasonably — understood as punishment. The best proof that the District’s testing program is to some extent accusatory can be found in James Acton’s own explanation on the witness stand as to why he did not want to submit to drug testing: “Because I feel that they have no *684reason to think I was taking drugs.” Tr. 13 (Apr. 29, 1992). It is hard to think of a manner of explanation that resonates more intensely in our Fourth Amendment tradition than this.

II

I do not believe that suspicionless drug testing is justified on these facts. But even if I agreed that some such testing were reasonable here, I see two other Fourth Amendment flaws in the District’s program.2 First, and most serious, there is virtually no evidence in the record of a drug problem at the Washington Grade School, which includes the seventh and eighth grades, and which Acton attended when this litigation began. This is not surprising, given that, of the four witnesses who testified to drug-related incidents, three were teachers and/or coaches at the high school, see Tr. 65; id., at 86; id., at 99, and the fourth, though the principal of the grade school at the time of the litigation, had been employed as principal of the high school during the years leading up to (and beyond) the implementation of the drug testing policy. See id., at 17. The only evidence of a grade school drug problem that my review of the record uncovered is a “guarantee” by the late-arriving grade school principal that “our problems we’ve had in ’88 and ’89 didn’t start at the high school level. They started in the elementary school.” Id., at 43. But I would hope that a single assertion of this sort would not serve as an adequate basis on which to uphold mass, suspicionless drug testing of two entire grades of student athletes — in Vernonia and, by the Court’s reasoning, in other school districts as well. Perhaps there is a drug problem at the grade school, but one would not know it from this *685record. At the least, then, I would insist that the parties and the District Court address this issue on remand.

Second, even as to the high school, I find unreasonable the school’s choice of student athletes as the class to subject to suspicionless testing — a choice that appears to have been driven more by a belief in what would pass constitutional muster, see id., at 45-47 (indicating that the original program was targeted at students involved in any extracurricular activity), than by a belief in what was required to meet the District’s principal disciplinary concern. Reading the full record in this case, as well as the District Court’s authoritative summary of it, 796 F. Supp. 1354, 1356-1357 (Ore. 1992), it seems quite obvious that the true driving force behind the District’s adoption of its drug testing program was the need to combat the rise in drug-related disorder and disruption in its classrooms and around campus. I mean no criticism of the strength of that interest. On the contrary, where the record demonstrates the existence of such a problem, that interest seems self-evidently compelling. “Without first establishing discipline and maintaining order, teachers cannot begin to educate their students.” I L. O., 469 U. S., at 350 (Powell, J., concurring). And the record in this case surely demonstrates there was a drug-related discipline problem in Vernonia of “‘epidemic proportions.’” 796 F. Supp., at 1357. The evidence of a drug-related sports injury problem at Vernonia, by contrast, was considerably weaker.

On this record, then, it seems to me that the far more reasonable choice would have been to focus on the class of students found to have violated published school rules against severe disruption in class and around campus, see Record, Exh. 2, at 9,11 — disruption that had a strong nexus to drug use, as the District established at trial. Such a choice would share two of the virtues of a suspicion-based regime: testing dramatically fewer students, tens as against hundreds, and giving students control, through their behav*686ior, over the likelihood that they would be tested. Moreover, there would be a reduced concern for the accusatory nature of the search, because the Court’s feared “badge of shame,” ante, at 663, would already exist, due to the antecedent accusation and finding of severe disruption. In a lesser known aspect of Skinner, we upheld an analogous testing scheme with little hesitation. See Skinner, 489 U. S., at 611 (describing “ ‘Authorization to Test for Cause’ ” scheme, according to which train operators would be tested “in the event of certain specific rule violations, including noncompliance with a signal and excessive speeding”).

III

It cannot be too often stated that the greatest threats to our constitutional freedoms come in times of crisis. But we must also stay mindful that not all government responses to such times are hysterical overreactions; some crises are quite real, and when they are, they serve precisely as the compelling state interest that we have said may justify a measured intrusion on constitutional rights. The only way for judges to mediate these conflicting impulses is to do what they should do anyway: stay close to the record in each case that appears before them, and make their judgments based on that alone. Having reviewed the record here, I cannot avoid the conclusion that the District’s suspicionless policy of testing all student athletes sweeps too broadly, and too imprecisely, to be reasonable under the Fourth Amendment.

Justice Thomas

delivered the opinion of the Court.

The Student Activities Drug Testing Policy implemented by the Board of Education of Independent School District No. 92 of Pottawatomie County (School District) requires all students who participate in competitive extracurricular activities to submit to drug testing. Because this Policy reasonably serves the School District’s important interest in detecting and preventing drug use among its students, we hold that it is constitutional.

*826HH

The city of Tecumseh, Oklahoma, is a rural community located approximately 40 miles southeast of Oklahoma City. The School District administers all Tecumseh public schools. In the fall of 1998, the School District adopted the Student Activities Drug Testing Policy (Policy), which requires all middle and high school students to consent to drug testing in order to participate in any extracurricular activity. In practice, the Policy has been applied only to competitive extracurricular activities sanctioned by the Oklahoma Secondary Schools Activities Association, such as the Academic Team, Future Farmers of America, Future Homemakers of America, band, choir, pom pon, cheerleading, and athletics. Under the Policy, students are required to take a drug test before participating in an extracurricular activity, must submit to random drug testing while participating in that activity, and must agree to be tested at any time upon reasonable suspicion. The urinalysis tests are designed to detect only the use of illegal drugs, including amphetamines, marijuana, cocaine, opiates, and barbituates, not medical conditions or the presence of authorized prescription medications.

At the time of their suit, both respondents attended Tecumseh High School. Respondent Lindsay Earls was a member of the show choir, the marching band, the Academic Team, and the National Honor Society. Respondent Daniel James sought to participate in the Academic Team.1 Together with their parents, Earls and James brought a Rev. *827Stat. § 1979, 42 U. S. C. § 1983, action against the School District, challenging the Policy both on its face and as applied to their participation in extracurricular activities.2 They alleged that the Policy violates the Fourth Amendment as incorporated by the Fourteenth Amendment and requested in-junctive and declarative relief. They also argued that the School District failed to identify a special need for testing students who participate in extracurricular activities, and that the “Drug Testing Policy neither addresses a proven problem nor promises to bring any benefit to students or the school.” App. 9.

Applying the principles articulated in Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995), in which we upheld the suspicionless drug testing of school athletes, the United States District Court for the Western District of Oklahoma rejected respondents’ claim that the Policy was unconstitutional and granted summary judgment to the School District. The court noted that “special needs” exist in the public school context and that, although the School District did “not show a drug problem of epidemic proportions,” there was a history of drug abuse starting in 1970 that presented “legitimate cause for concern.” 115 F. Supp. 2d 1281, 1287 (2000). The District Court also held that the Policy was effective because “[i]t can scarcely be disputed that the drug problem among the student body is effectively addressed by making sure that the large number of students participating in competitive, extracurricular activities do not use drugs.” Id., at 1295.

The United States Court of Appeals for the Tenth Circuit reversed, holding that the Policy violated the Fourth Amendment. The Court of Appeals agreed with the District Court that the Policy must be evaluated in the “unique environment of the school setting,” but reached a different conclu*828sion as to the Policy’s constitutionality. 242 F. 3d 1264, 1270 (2001). Before imposing a suspicionless drug testing program, the Court of Appeals concluded that a school “must demonstrate that there is some identifiable drug abuse problem among a sufficient number of those subject to the testing, such that testing that group of students will actually redress its drug problem.” Id., at 1278. The Court of Appeals then held that because the School District failed to demonstrate such a problem existed among Tecumseh students participating in competitive extracurricular activities, the Policy was unconstitutional. We granted certiorari, 534 U. S. 1015 (2001), and now reverse.

II

The Fourth Amendment to the United States Constitution protects “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures.” Searches by public school officials, such as the collection of urine samples, implicate Fourth Amendment interests. See Vernonia, supra, at 652; cf. New Jersey v. T. L. O., 469 U. S. 325, 334 (1985). We must therefore review the School District’s Policy for “reasonableness,” which is the touchstone of the constitutionality of a governmental search.

In the criminal context, reasonableness usually requires a showing of probable cause. See, e. g., Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 619 (1989). The probable-cause standard, however, “is peculiarly related to criminal investigations” and may be unsuited to determining the reasonableness of administrative searches where the “Government seeks to prevent the development of hazardous conditions.” Treasury Employees v. Von Raab, 489 U. S. 656, 667-668 (1989) (internal quotation marks and citations omitted) (collecting eases). The Court has also held that a warrant and finding of probable cause are unnecessary in the public school context because such requirements “ ‘would unduly interfere with the maintenance of the swift and infor*829mal disciplinary procedures [that are] needed.’ ” Vernonia, supra, at 653 (quoting T L. O., supra, at 340-341).

Given that the School District’s Policy is not in any way related to the conduct of criminal investigations, see Part II-B, infra, respondents do not contend that the School District requires probable cause before testing students for drug use. Respondents instead argue that drug testing must be based at least on some level of individualized suspicion. See Brief for Respondents 12-14. It is true that we generally determine the reasonableness of a search by balancing the nature of the intrusion on the individual’s privacy against the promotion of legitimate governmental interests. See Delaware v. Prouse, 440 U. S. 648, 654 (1979). But we have long held that “the Fourth Amendment imposes no irreducible requirement of [individualized] suspicion.” United States v. Martinez-Fuerte, 428 U. S. 543, 561 (1976). “[I]n certain limited circumstances, the Government’s need to discover such latent or hidden conditions, or to prevent their development, is sufficiently compelling to justify the intrusion on privacy entailed by conducting such searches without any measure of individualized suspicion.” Von Raab, supra, at 668; see also Skinner, supra, at 624. Therefore, in the context of safety and administrative regulations, a search unsupported by probable cause may be reasonable “when 'special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.’” Griffin v. Wisconsin, 483 U. S. 868, 873 (1987) (quoting T. L. O., supra, at 351 (Blackmun, J., concurring in judgment)); see also Vernonia, supra, at 653; Skinner, supra, at 619.

Significantly, this Court has previously held that “special needs” inhere in the public school context. See Vernonia, supra, at 653; T. L. O., supra, at 339-340. While schoolchildren do not shed their constitutional rights when they enter the schoolhouse, see Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 506 (1969), “Fourth *830Amendment rights . . . are different in public schools than elsewhere; the ‘reasonableness’ inquiry cannot disregard the schools’ custodial and tutelary responsibility for children.” Vernonia, 515 U. S., at 656. In particular, a finding of individualized suspicion may not be necessary when a school conducts drug testing.

In Vernonia, this Court held that the suspicionless drug testing of athletes was constitutional. The Court, however, did not simply authorize all school drug testing, but rather conducted a fact-specific balancing of the intrusion on the children’s Fourth Amendment rights against the promotion of legitimate governmental interests. See id., at 652-653. Applying the principles of Vernonia to the somewhat different facts of this case, we conclude that Tecumseh’s Policy is also constitutional.

A

We first consider the nature of the privacy interest allegedly compromised by the drug testing. See id., at 654. As in Vernonia, the context of the public school environment serves as the backdrop for the analysis of the privacy interest at stake and the reasonableness of the drug testing policy in general. See ibid. (“Central... is the fact that the subjects of the Policy are (1) children, who (2) have been committed to the temporary custody of the State as schoolmaster”); see also id., at 665 (“The most significant element in this case is the first we discussed: that the Policy was undertaken in furtherance of the government’s responsibilities, under a public school system, as guardian and tutor of children entrusted to its care”); ibid. (“[W]hen the government acts as guardian and tutor the relevant question is whether the search is one that a reasonable guardian and tutor might undertake”).

A student’s privacy interest is limited in a public school environment where the State is responsible for maintaining discipline, health, and safety. Schoolchildren are routinely required to submit to physical examinations and vaccinations *831against disease. See id., at 656. Securing order in the school environment sometimes requires that students be subjected to greater controls than those appropriate for adults. See T. L. O., 469 U. S., at 350 (Powell, J., concurring) (“Without first establishing discipline and maintaining order, teachers cannot begin to educate their students. And apart from education, the school has the obligation to protect pupils from mistreatment by other children, and also to protect teachers themselves from violence by the few students whose conduct in recent years has prompted national concern”).

Respondents argue that because children participating in nonathletic extracurricular activities are not subject to regular physicals and communal undress, they have a stronger expectation of privacy than the athletes tested in Vernonia. See Brief for Respondents 18-20. This distinction, however, was not essential to our decision in Vernonia, which depended primarily upon the school’s custodial responsibility and authority.3

In any event, students who participate in competitive extracurricular activities voluntarily subject themselves to many of the same intrusions on their privacy as do athletes.4 *832Some of these clubs and activities require occasional off-campus travel and communal undress. All of them have their own rules and requirements for participating students that do not apply to the student body as a whole. 115 F. Supp. 2d, at 1289-1290. For example, each of the competitive extracurricular activities governed by the Policy must abide by the rules of the Oklahoma Secondary Schools Activities Association, and a faculty sponsor monitors the students for compliance with the various rules dictated by the clubs and activities. See id., at 1290. This regulation of extracurricular activities further diminishes the expectation of privacy among schoolchildren. Cf. Vernonia, supra, at 657 (“Somewhat like adults who choose to participate in a closely regulated industry, students who voluntarily participate in school athletics have reason to expect intrusions upon normal rights and privileges, including privacy” (internal quotation marks omitted)). We therefore conclude that the students affected by this Policy have a limited expectation of privacy.

B

Next, we consider the character of the intrusion imposed by the Policy. See Vernonia, supra, at 658. Urination is “an excretory function traditionally shielded by great privacy.” Skinner, 489 U. S., at 626. But the “degree of intrusion” on one’s privacy caused by collecting a urine sample “depends upon the manner in which production of the urine sample is monitored.” Vernonia, supra, at 658.

Under the Policy, a faculty monitor waits outside the closed restroom stall for the student to produce a sample and must “listen for the normal sounds of urination in order to guard against tampered specimens and to insure an accurate chain of custody.” App. 199. The monitor then pours the sample into two bottles that are sealed and placed into a mailing pouch along with a consent form signed by the student. This procedure is virtually identical to that reviewed in Vernonia, except that it additionally protects privacy by *833allowing male students to produce their samples behind a closed stall. Given that we considered the method of collection in Vernonia a “negligible” intrusion, 515 U. S., at 658, the method here is even less problematic.

In addition, the Policy clearly requires that the test results be kept in confidential files separate from a student’s other educational records and released to school personnel only on a “need to know” basis. Respondents nonetheless contend that the intrusion on students’ privacy is significant because the Policy fails to protect effectively against the disclosure of confidential information and, specifically, that the school “has been careless in protecting that information: for example, the Choir teacher looked at students’ prescription drug lists and left them where other students could see them.” Brief for Respondents 24. But the choir teacher is someone with a “need to know,” because during off-campus trips she needs to know what medications are taken by her students. Even before the Policy was enacted the choir teacher had access to this information. See App. 132. In any event, there is no allegation that any other student did see such information. This one example of alleged carelessness hardly increases the character of the intrusion.

Moreover, the test results are not turned over to any law enforcement authority. Nor do the test results here lead to the imposition of discipline or have any academic consequences. Cf. Vernonia, supra, at 658, and n. 2. Rather, the only consequence of a failed drug test is to limit the student’s privilege of participating in extracurricular activities. Indeed, a student may test positive for drugs twice and still be allowed to participate in extracurricular activities. After the first positive test, the school contacts the student’s parent or guardian for a meeting. The student may continue to participate in the activity if within five days of the meeting the student shows proof of receiving drug counseling and submits to a second drug test in two weeks. For the second positive test, the student is suspended from participation in *834all extracurricular activities for 14 days, must complete four hours of substance abuse counseling, and must submit to monthly drug tests. Only after a third positive test will the student be suspended from participating in any extracurricular activity for the remainder of the school year, or 88 school days, whichever is longer. See App. 201-202.

Given the minimally intrusive nature of the sample collection and the limited uses to which the test results are put, we conclude that the invasion of students’ privacy is not significant.

C

Finally, this Court must consider the nature and immediacy of the government’s concerns and the efficacy of the Policy in meeting them. See Vernonia, 515 U. S., at 660. This Court has already articulated in detail the importance of the governmental concern in preventing drug use by schoolchildren. See id., at 661-662. The drug abuse problem among our Nation’s youth has hardly abated since Vernonia was decided in 1995. In fact, evidence suggests that it has only grown worse.5 As in Vernonia, “the necessity for the State to act is magnified by the fact that this evil is being visited not just upon individuals at large, but upon children for whom it has undertaken a special responsibility of care and direction.” Id., at 662. The health and safety risks identified in Vernonia apply with equal force to Tecumseh’s children. Indeed, the nationwide drug epidemic makes the war against drugs a pressing concern in every school.

Additionally, the School District in this case has presented specific evidence of drug use at Tecumseh schools. Teachers testified that they had seen students who appeared to be *835under the influence of drugs and that they had heard students speaking-openly about using drugs. See, e. g., App. 72 (deposition of Dean Rogers); id., at 115 (deposition of Sheila Evans). A drug dog found marijuana cigarettes near the school parking lot. Police officers once found drugs or drug paraphernalia in a car driven by a Future Farmers of America member. And the school board president reported that people in the community were calling the board to discuss the ‘‘drug situation.” See 115 F. Supp. 2d, at 1285-1286. We decline to second-guess the finding of the District Court that “[viewing the evidence as a whole, it cannot be reasonably disputed that the [School District] was faced with a ‘drug problem’ when it adopted the Policy.” Id., at 1287.

Respondents consider the proffered evidence insufficient and argue that there is no “real and immediate interest” to justify a policy of drug testing nonathletes. Brief for Respondents 32. We have recognized, however, that “[a] demonstrated problem of drug abuse . . . [is] not in all cases necessary to the validity of a testing regime,” but that some showing does “shore up an assertion of special need for a suspieionless general search program.” Chandler v. Miller, 520 U. S. 305, 319 (1997). The School District has provided sufficient evidence to shore up the need for its drug testing program.

Furthermore, this Court has not required a particularized or pervasive drug problem before allowing the government to conduct suspicionless drug testing. For instance, in Von Raab the Court upheld the drug testing of customs officials on a purely preventive basis, without any documented history of drug use by such officials. See 489 U. S., at 673. In response to the lack of evidence relating to drug use, the Court noted generally that “drug abuse is one of the most serious problems confronting our society today,” and that programs to prevent and detect drug use among customs officials could not be deemed unreasonable. Id., at 674; cf. Skinner, 489 U. S., at 607, and n. 1 (noting nationwide *836studies that identified on-the-job alcohol and drug use by railroad employees). Likewise, the need to prevent and deter the substantial harm of childhood drug use provides the necessary immediacy for a school testing policy. Indeed, it would make little sense to require a school district to wait for a substantial portion of its students to begin using drugs before it was allowed to institute a drug testing program designed to deter drug use.

Given the nationwide epidemic of drug use, and the evidence of increased drug use in Tecumseh schools, it was entirely reasonable for the School District to enact this particular drug testing policy. We reject the Court of Appeals’ novel test that “any district seeking to impose a random sus-picionless drug testing policy as a condition to participation in a school activity must demonstrate that there is some identifiable drug abuse problem among a sufficient number of those subject to the testing, such that testing that group of students will actually redress its drug problem.” 242 F. 3d, at 1278. Among other problems, it would be difficult to administer such a test. As we cannot articulate a threshold level of drug use that would suffice to justify a drug testing program for schoolchildren, we refuse to fashion what would in effect be a constitutional quantum of drug use necessary to show a “drug problem.”

Respondents also argue that the testing of nonathletes does not implicate any safety concerns, and that safety is a “crucial factor” in applying the special needs framework. Brief for Respondents 25-27. They contend that there must be “surpassing safety interests,” Skinner, supra, at 634, or “extraordinary safety and national security hazards,” Von Raab, supra, at 674, in order to override the usual protections of the Fourth Amendment. See Brief for Respondents 25-26. Respondents are correct that safety factors into the special needs analysis, but the safety interest furthered by drug testing is undoubtedly substantial for all children, athletes and nonathletes alike. We know all too well that drug *837use carries a variety of health risks for children, including death from overdose.

We also reject respondents’ argument that drug testing must presumptively be based upon an individualized reasonable suspicion of wrongdoing because such a testing regime would be less intrusive. See id., at 12-16. In this context, the Fourth Amendment does not require a finding of individualized suspicion, see supra, at 829, and we decline to impose such a requirement on schools attempting to prevent and detect drug use by students. Moreover, we question whether testing based on individualized suspicion in fact would be less intrusive. Such a regime would place an additional burden on public school teachers who are already tasked with the difficult job of maintaining order and discipline. A program of individualized suspicion might unfairly target members of unpopular groups. The fear of lawsuits resulting from such targeted searches may chill enforcement of the program, rendering it ineffective in combating drug use. See Vernonia, 515 U. S., at 668-664 (offering similar reasons for why “testing based on ‘suspicion’ of drug use would not be better, but worse”). In any case, this Court has repeatedly stated that reasonableness under the Fourth Amendment does not require employing the least intrusive means, because “[t]he logic of such elaborate less-restrictive-alternative arguments could raise insuperable barriers to the exercise of virtually all search-and-seizure powers.” Martinez-Fuerte, 428 U. S., at 556-557, n. 12; see also Skinner, supra, at 624 (“[A] showing of individualized suspicion is not a constitutional floor, below which a search must be presumed unreasonable”).

Finally, we find that testing students who participate in extracurricular activities is a reasonably effective means of addressing the School District’s legitimate concerns in preventing, deterring, and detecting drug use. While in Ver-nonia there might have been a closer fit between the testing of athletes and the trial court’s finding that the drug problem *838was “fueled by the ‘role model’ effect of athletes’ drug use,” such a finding was not essential to the holding. 515 U. S., at 663; cf. id., at 684-685 (O’Connor, J., dissenting) (questioning the extent of the drug problem, especially as applied to athletes). Vernonia did not require the school to test the group of students most likely to use drugs, but rather considered the constitutionality of the program in the context of the public school’s custodial responsibilities. Evaluating the Policy in this context, we conclude that the drug testing of Tecumseh students who participate in extracurricular activities effectively serves the School District’s interest in protecting the safety and health of its students.

HH l-H l — H

Within the limits of the Fourth Amendment, local school boards must assess the desirability of drug testing schoolchildren. In upholding the constitutionality of the Policy, we express no opinion as to its wisdom. Rather, we hold only that Tecumseh’s Policy is a reasonable means of furthering the School District’s important interest in preventing and deterring drug use among its schoolchildren. Accordingly, we reverse the judgment of the Court of Appeals.

It is so ordered.

Justice Breyer,

concurring.

I agree with the Court that Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995), governs this case and requires reversal of the Tenth Circuit’s decision. The school’s drug testing program addresses a serious national problem by focusing upon demand, avoiding the use of criminal or disciplinary sanctions, and relying upon professional counseling and treatment. See App. 201-202. In my view, this program does not violate the Fourth Amendment’s prohibition of “unreasonable searches and seizures.” I reach this conclusion primarily for the reasons given by the Court, but I would *839emphasize several underlying considerations, which I understand to be consistent with the Court’s opinion.

I

In respect to the school’s need for the drug testing program, I would emphasize the following: First, the drug problem in our Nation’s schools is serious in terms of size, the kinds of drugs being used, and the consequences of that use both for our children and the rest of us. See, e. g., White House Nat. Drug Control Strategy 25 (Feb. 2002) (drug abuse leads annually to about 20,000 deaths, $160 billion in economic costs); Department of Health and Human Services, L. Johnston et al., Monitoring the Future: National Results on Adolescent Drug Use, Overview of Key Findings 5 (2001) (Monitoring the Future) (more than one-third of all students have used illegal drugs before completing the eighth grade; more than half before completing high school); ibid, (about 30% of all students use drugs other than marijuana prior to completing high school (emphasis added)); National Center on Addiction and Substance Abuse, Malignant Neglect: Substance Abuse and America’s Schools 15 (Sept. 2001) (Malignant Neglect) (early use leads to later drug dependence); Nat. Drug Control Strategy, supra, at 1 (same).

Second, the government’s emphasis upon supply side interdiction apparently has not reduced teenage use in recent years. Compare R. Perl, CRS Issue Brief for Congress, Drug Control: International Policy and Options CRS-1 (Dec. 12, 2001) (supply side programs account for 66% of the federal drug control budget), with Partnership for a Drug-Free America, 2001 Partnership Attitude Tracking Study: Key Findings 1 (showing increase in teenage drug use in early 1990’s, peak in 1997, holding steady thereafter); 2000-2001 PRIDE National Summary: Alcohol, Tobacco, Illicit Drugs, Violence and Related Behaviors, Grades 6 thru 12 (Jul. 16, 2002), http://www.pridesurveys.com/main/supportfiles/ natsum00.pdf, p. 15 (slight rise in high school drug use in *8402000-2001); Monitoring the Future, Table 1 (lifetime prevalence of drug use increasing over last 10 years).

Third, public school systems must find effective ways to deal with this problem. Today’s public expects its schools not simply to teach the fundamentals, but “to shoulder the burden of feeding students breakfast and lunch, offering before and after school child care services, and providing medical and psychological services,” all in a school environment that is safe and encourages learning. Brief for National School Boards Association et al. as Amici Curiae 3-4. See also Bethel School Dist. No. 403 v. Fraser, 478 U. S. 675, 681 (1986) (Schools “ ‘prepare pupils for citizenship in the Republic [and] inculcate the habits and manners of civility as values in themselves conductive to happiness and as indispensable to the practice of self-government in the community and the nation’ ”) (quoting C. Beard & M. Beard, New Basic History of the United States 228 (1968)). The law itself recognizes these responsibilities with the phrase in loco parentis — a phrase that draws its legal force primarily from the needs of younger students (who here are necessarily grouped together with older high school students) and which reflects, not that a child or adolescent lacks an interest in privacy, but that a child’s or adolescent’s school-related privacy interest, when compared to the privacy interests of an adult, has different dimensions. Cf. Vernonia, supra, at 654-655. A public school system that fails adequately to carry out its responsibilities may well see parents send their children to private or parochial school instead — with help from the State. See Zelman v. Simmons-Harris, ante, p. 639.

Fourth, the program at issue here seeks to discourage demand for drugs by changing the school’s environment in order to combat the single most important factor leading schoolchildren to take drugs, namely, peer pressure. Malignant Neglect 4 (students “whose friends use illicit drugs are more than 10 times likelier to use illicit drugs than those whose friends do not”). It offers the adolescent a nonthreat*841ening reason to decline his friend’s drug-use invitations, namely, that he intends to play baseball, participate in debate, join the band, or engage in any one of half a dozen useful, interesting, and important activities.

II

In respect to the privacy-related burden that the drug testing program imposes upon students, I would emphasize the following: First, not everyone would agree with this Court’s characterization of the privacy-related significance of urine sampling as “‘negligible.’” Ante, at 833 (quoting Vernonia, 515 U. S., at 658). Some find the procedure no more intrusive than a routine medical examination, but others are seriously embarrassed by the need to provide a urine sample with someone listening “outside the closed restroom stall,” ante, at 832. When trying to resolve this kind of close question involving the interpretation of constitutional values, I believe it important that the school board provided an opportunity for the airing of these differences at public meetings designed to give the entire community “the opportunity to be able to participate” in developing the drug policy. App. 87. The board used this democratic, participatory process to uncover and to resolve differences, giving weight to the fact that the process, in this instance, revealed little, if any, objection to the proposed testing program.

Second, the testing program avoids subjecting the entire school to testing. And it preserves an option for a conscientious objector. He can refuse testing while paying a price (nonparticipation) that is serious, but less severe than expulsion from the school.

Third, a contrary reading of the Constitution, as requiring “individualized suspicion” in this public school context, could well lead schools to push the boundaries of “individualized suspicion” to its outer limits, using subjective criteria that may “unfairly target members of impopular groups,” ante, at 837, or leave those whose behavior is slightly abnormal *842stigmatized in the minds of others. See Belsky, Random vs. Suspicion-Based Drug Testing in the Public Schools — A Surprising Civil Liberties Dilemma, 27 Okla. City U. L. Rev. 1, 20-21 (forthcoming 2002) (listing court-approved factors justifying suspicion-based drug testing, including tiredness, overactivity, quietness, boisterousness, sloppiness, excessive meticulousness, and tardiness). If so, direct application of the Fourth Amendment’s prohibition against “unreasonable searches and seizures” will further that Amendment’s liberty-protecting objectives at least to the same extent as application of the mediating “individualized suspicion” test, where, as here, the testing program is neither criminal nor disciplinary in nature.

* * *

I cannot know whether the school’s drug testing program will work. But, in my view, the Constitution does not prohibit the effort. Emphasizing the considerations I have mentioned, along with others to which the Court refers, I conclude that the school’s drug testing program, constitutionally speaking, is not “unreasonable.” And I join the Court’s opinion.

Justice O’Connor,

with whom Justice Souter joins, dissenting.

I dissented in Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995), and continue to believe that case was wrongly decided. Because Vernonia is now this Court’s precedent, and because I agree that petitioners’ program fails even under the balancing approach adopted in that case, I join Justice Ginsburg’s dissent.

Justice Ginsburg,

with whom Justice Stevens, Justice O’Connor, and Justice Souter join, dissenting.

Seven years ago, in Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995), this Court determined that a school *843district’s policy of randomly testing the urine of its student athletes for illicit drugs did not violate the Fourth Amendment. In so ruling, the Court emphasized that drug use “increase[d] the risk of sports-related injury” and that Ver-nonia’s athletes were the “leaders” of an aggressive local “drug culture” that had reached “‘epidemic proportions.’” Id., at 649. Today, the Court relies upon Vernonia to permit a school district with a drug problem its superintendent repeatedly described as “not. . . major,” see App. 180, 186, 191, to test the urine of an academic team member solely by reason of her participation in a nonathletic, competitive extracurricular activity — participation associated with neither special dangers from, nor particular predilections for, drug use.

“[T]he legality of a search of a student,” this Court has instructed, “should depend simply on the reasonableness, under all the circumstances, of the search.” New Jersey v. T. L. O., 469 U. S. 325, 341 (1985). Although “ ‘special needs’ inhere in the public school context,” see ante, at 829 (quoting Vernonia, 515 U. S., at 653), those needs are not so expansive or malleable as to render reasonable any program of student drug testing a school district elects to install. The particular testing program upheld today is not reasonable; it is capricious, even perverse: Petitioners’ policy targets for testing a student population least likely to be at risk from illicit drugs and their damaging effects. I therefore dissent.

1 — <

A

A search unsupported by probable cause nevertheless may be consistent with the Fourth Amendment “when special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.” Griffin v. Wisconsin, 483 U. S. 868, 873 (1987) (internal quotation marks omitted). In Vernonia, this Court made clear that “such ‘special needs’ . . . exist in the public school con*844text.” 515 U. S., at 653 (quoting Griffin, 483 U. S., at 873). The Court observed:

“[Wjhile children assuredly do not ‘shed their constitutional rights ... at the schoolhouse gate,’ Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 506 (1969), the nature of those rights is what is appropriate for children in school.... Fourth Amendment rights, no less than First and Fourteenth Amendment rights, are different in public schools than elsewhere; the ‘reasonableness’ inquiry cannot disregard the schools’ custodial and tutelary responsibility for children.” 515 U. S., at 655-656 (other citations omitted).

The Vernonia Court concluded that a public school district facing a disruptive and explosive drug abuse problem sparked by members of its athletic teams had “special needs” that justified suspicionless testing of district athletes as a condition of their athletic participation.

This case presents circumstances dispositively different from those of Vernonia. True, as the Court stresses, Tecumseh students participating in competitive extracurricular activities other than athletics share two relevant characteristics with the athletes of Vernonia. First, both groups attend public schools. “[0]ur decision in Vernonia,” the Court states, “depended primarily upon the school’s custodial responsibility and authority.” Ante, at 831; see also ante, at 840 (Breyer, J., concurring) (school districts act in loco parentis). Concern for student health and safety is basic to the school’s caretaking, and it is undeniable that “drug use carries a variety of health risks for children, including death from overdose.” Ante, at 836-837 (majority opinion).

Those risks, however, are present for all schoolchildren. Vernonia cannot be read to endorse invasive and suspicion-less drug testing of all students upon any evidence of drug use, solely because drugs jeopardize the life and health of those who use them. Many children, like many adults, en*845gage in dangerous activities on their own time; that the children are enrolled in school scarcely allows government to monitor all such activities. If a student has a reasonable subjective expectation of privacy in the personal items she brings to school, see T. L. O., 469 U. S., at 338-339, surely she has a similar expectation regarding the chemical composition of her urine. Had the Vernonia Court agreed that public school attendance, in and of itself, permitted the State to test each student’s blood or urine for drugs, the opinion in Vernonia could have saved many words. See, e. g., 515 U. S., at 662 (“[I]t must not be lost sight of that [the Vernonia School District] program is directed ... to drug use by school athletes, where the risk of immediate physical harm to the drug user or those with whom he is playing his sport is particularly high.”).

The second commonality to which the Court points is the voluntary character of both interscholastic athletics and other competitive extracurricular activities. “By choosing to ‘go out for the team,’ [school athletes] voluntarily subject themselves to a degree of regulation even higher than that imposed on students generally.” Id., at 657. Comparably, the Court today observes, “students who participate in competitive extracurricular activities voluntarily subject themselves to” additional rules not applicable to other students. Ante, at 831.

The comparison is enlightening. While extracurricular activities are “voluntary” in the sense that they are not required for graduation, they are part of the school’s educational program; for that reason, the petitioner (hereinafter School District) is justified in expending public resources to ■ make them available. Participation in such activities is a key component of school life, essential in reality for students applying to college, and, for all participants, a significant contributor to the breadth and quality of the educational experience. See Brief for Respondents 6; Brief for American Academy of Pediatrics et al. as Amici Curiae 8-9. Students *846“volunteer” for extracurricular pursuits in the same way they might volunteer for honors classes: They subject themselves to additional requirements, but they do so in order to take full advantage of the education offered them. Cf. Lee v. Weisman, 505 U. S. 577, 595 (1992) (“Attendance may not be required by official decree, yet it is apparent that a student is not free to absent herself from the graduation exercise in any real sense of the term ‘voluntary,’ for absence would require forfeiture of those intangible benefits which have motivated the student through youth and all her high school years.”).

Voluntary participation in athletics has a distinctly different dimension: Schools regulate student athletes discretely because competitive school sports by their nature require communal undress and, more important, expose students to physical risks that schools have a duty to mitigate. For the very reason that schools cannot offer a program of competitive athletics without intimately affecting the privacy of students, Vernonia reasonably analogized school athletes to “adults who choose to participate in a closely regulated industry.” 515 U. S., at 657 (internal quotation marks omitted). Industries fall within the closely regulated category when the nature of their activities requires substantial government oversight. See, e. g., United States v. Biswell, 406 U. S. 311, 815-316 (1972). Interscholastic athletics similarly require close safety and health regulation; a school’s choir, band, and academic team do not.

In short, Vernonia applied, it did not repudiate, the principle that “the legality of a search of a student should depend simply on the reasonableness, under all the circumstances, of the search.” T. L. O., 469 U. S., at 341 (emphasis added). Enrollment in a public school, and election to participate in school activities beyond the bare minimum that the curriculum requires, are indeed factors relevant to reasonableness, but they do not on their own justify intrusive, suspicionless searches. Vernonia, accordingly, did not rest upon these *847factors; instead, the Court performed what today’s majority aptly describes as a “fact-specific balancing,” ante, at 830. Balancing of that order, applied to the facts now before the Court, should yield a result other than the one the Court announces today.

B

Vernonia initially considered “the nature of the privacy interest upon which the search [there] at issue intrude[d].” 515 U. S., at 654. The Court emphasized that student athletes’ expectations of privacy are necessarily attenuated:

“Legitimate privacy expectations are even less with regard to student athletes. School sports are not for the bashful. They require ‘suiting up’ before each practice or event, and showering and changing afterwards. Public school locker rooms, the usual sites for these activities, are not notable for the privacy they afford. The locker rooms in Vernonia are typical: No individual dressing rooms are provided; shower heads are lined up along a wall, unseparated by any sort of partition or curtain; not even all the toilet stalls have doors. . . . [T]here is an element of communal undress inherent in athletic participation.” Id., at 657 (internal quotation marks omitted).

Competitive extracurricular activities other than athletics, however, serve students of all manner: the modest and shy along with the bold and uninhibited. Activities of the kind plaintiff-respondent Lindsay Earls pursued — choir, show choir, marching band, and academic team — afford opportunities to gain self-assurance, to “come to know faculty members in a less formal setting than the typical classroom,” and to acquire “positive social supports and networks [that] play a critical role in periods of heightened stress.” Brief for American Academy of Pediatrics et al. as Amici Curiae 13.

On “occasional out-of-town trips,” students like Lindsay Earls “must sleep together in communal settings and use *848communal bathrooms.” 242 F. 3d 1264, 1275 (CA10 2001). But those situations are hardly equivalent to the routine communal undress associated with athletics; the School District itself admits that when such trips occur, “public-like restroom facilities,” which presumably include enclosed stalls, are ordinarily available for changing, and that “more modest students” find other ways to maintain their privacy. Brief for Petitioners 34.1

After describing school athletes’ reduced expectation of privacy, the Vernonia Court turned to “the character of the intrusion . . . complained of.” 515 U. S., at 658. Observing that students produce urine samples in a bathroom stall with a coach or teacher outside, Vernonia typed the privacy interests compromised by the process of obtaining samples “negligible.” Ibid. As to the required pretest disclosure of prescription medications taken, the Court assumed that “the School District would have permitted [a student] to provide the requested information in a confidential manner — for example, in a sealed envelope delivered to the testing lab.” Id., at 660. On that assumption, the Court concluded that Vernonia’s athletes faced no significant invasion of privacy.

In this case, however, Lindsay Earls and her parents allege that the School District handled personal information collected under the policy carelessly, with little regard for its confidentiality. Information about students’ prescription drug use, they assert, was routinely viewed by Lindsay’s choir teacher, who left files containing the information unlocked and unsealed, where others, including students, could see them; and test results were given out to all activity sponsors whether or not they had a clear “need to know.” See *849Brief for Respondents 6, 24; App. 105-106, 131. But see id., at 199 (policy requires that “[t]he medication list shall be submitted to the lab in a sealed and confidential envelope and shall not be viewed by district employees”).

In granting summary judgment to the School District, the District Court observed that the District’s “[pjolicy expressly provides for confidentiality of test results, and the Court must assume that the confidentiality provisions will be honored.” 115 F. Supp. 2d 1281, 1293 (WD Okla. 2000). The assumption is unwarranted. Unlike Vernonia, where the District Court held a bench trial before ruling in the School District’s favor, this case was decided by the District Court on summary judgment. At that stage, doubtful matters should not have been resolved in favor of the judgment seeker. See United States v. Diebold, Inc., 369 U. S. 654, 655 (1962) (per curiam) (“On summary judgment the inferences to be drawn from the underlying facts contained in [affidavits, attached exhibits, and depositions] must be viewed in the light most favorable to the party opposing the motion.”); see also 10A C. Wright, A. Miller, & M. Kane, Federal Practice and Procedure § 2716, pp. 274-277 (3d ed. 1998).

Finally, the “nature and immediacy of the governmental concern,” Vernonia, 515 U. S., at 660, faced by the Vernonia School District dwarfed that confronting Tecumseh administrators. Vernonia initiated its drug testing policy in response to an alarming situation: “[A] large segment of the student body, particularly those involved in interscholastic athletics, was in a state of rebellion ... fueled by alcohol and drug abuse as well as the student[s’] misperceptions about the drug culture.” Id., at 649 (internal quotation marks omitted). Tecumseh, by contrast, repeatedly reported to the Federal Government during the period leading up to the adoption of the policy that “types of drugs [other than alcohol and tobacco] including controlled dangerous substances, are present [in the schools] but have not identified themselves as major problems at this time.” 1998-1999 Tecum*850seh School’s Application for Funds under the Safe and Drug-Free Schools and Communities Program, reprinted at App. 191; accord, 1996-1997 Application, reprinted at App. 186; 1995-1996 Application, reprinted at App. 180.2 As the Tenth Circuit observed, “without a demonstrated drug abuse problem among the group being tested, the efficacy of the District’s solution to its perceived problem is . . . greatly diminished.” 242 F. 3d, at 1277.

The School District cites Treasury Employees v. Von Raab, 489 U. S. 656, 673-674 (1989), in which this Court permitted random drug testing of customs agents absent “any perceived drug problem among Customs employees,” given that “drug abuse is one of the most serious problems confronting our society today.” See also Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 607, and n. 1 (1989) (upholding random drug and alcohol testing of railway employees based upon industry-wide, rather than railway-specific, evidence of drug and alcohol problems). The tests in Von Raab and Railway Labor Executives, however, were installed to avoid enormous risks to the lives and limbs of others, not dominantly in response to the health risks to users invariably present in any case of drug use. See Von Raab, 489 U. S., at 674 (drug use by customs agents involved in drug interdiction creates “extraordinary safety and national security hazards”); Railway Labor Executives, 489 U. S., at 628 (railway operators “discharge duties fraught with such risks of injury to others that even a momentary lapse of attention can have disastrous consequences”); see *851also Chandler v. Miller, 520 U. S. 305, 321 (1997) (“Von Raab must be read in its unique context”).

Not only did the Vernonia and Tecumseh districts confront drug problems of distinctly different magnitudes, they also chose different solutions: Vernonia limited its policy to athletes; Tecumseh indiscriminately subjected to testing all participants in competitive extracurricular activities. Urging that “the safety interest furthered by drug testing is undoubtedly substantial for all children, athletes and nonath-letes alike,” ante, at 836, the Court cuts out an element essential to the Vernonia judgment. Citing medical literature on the effects of combining illicit drug use with physical exertion, the Vernonia Court emphasized that “the particular drugs screened by [Vernonia’s] Policy have been demonstrated to pose substantial physical risks to athletes.” 515 U. S., at 662; see also id., at 666 (Ginsburg, J., concurring) (Vernonia limited to “those seeking to engage with others in team sports”). We have since confirmed that these special risks were necessary to our decision in Vernonia. See Chandler, 520 U. S., at 317 (Vernonia “emphasized the importance of deterring drug use by schoolchildren and the risk of injury a drug-using student athlete cast on himself and those engaged with him on the playing field”); see also Ferguson v. Charleston, 532 U. S. 67, 87 (2001) (Kennedy, J., concurring) (Vernonia’s policy had goal of “ ‘[djeterring drug use by our Nation’s schoolchildren,’ and particularly by student-athletes, because ‘the risk of immediate physical harm to the drug user or those with whom he is playing his sport is particularly high’ ”) (quoting Vernonia, 515 U. S., at 661-662).

At the margins, of course, no policy of random drug testing is perfectly tailored to the harms it seeks to address. The School District cites the dangers faced by members of the band, who must “perform extremely precise routines with heavy equipment and instruments in close proximity to other students,” and by Future Farmers of America, who *852“are required to individually control and restrain animals as large as 1500 pounds.” Brief for Petitioners 43. For its part, the United States acknowledges that “the linebacker faces a greater risk of serious injury if he takes the field under the influence of drugs than the drummer in the halftime band,” but parries that “the risk of injury to a student who is under the influence of drugs while playing golf, cross country, or volleyball (sports covered by the policy in Ver-nonia) is scarcely any greater than the risk of injury to a student... handling a 1500-pound steer (as [Future Farmers of America] members do) or working with cutlery or other sharp instruments (as [Future Homemakers of America] members do).” Brief for United States as Amicus Curiae 18. One can demur to the Government’s view of the risks drug use poses to golfers, cf. PGA TOUR, Inc. v. Martin, 532 U. S. 661, 687 (2001) (“golf is a low intensity activity”), for golfers were surely as marginal among the linebackers, sprinters, and basketball players targeted for testing in Ver-nonia as steer-handlers are among the choristers, musicians, and academic-team members subject to urinalysis in Tecumseh.3 Notwithstanding nightmarish images of out-of-control flatware, livestock run amok, and colliding tubas disturbing the peace and quiet of Tecumseh, the great majority of students the School District seeks to test in truth are engaged in activities that are not safety sensitive to an unusual degree. There is a difference between imperfect tailoring and no tailoring at all.

The Vernonia district, in sum, had two good reasons for testing athletes: Sports team members faced special health risks and they “were the leaders of the drug culture.” Vernonia, 515 U. S., at 649. No similar reason, and no other tenable justification, explains Teeumseh’s decision to target *853for testing all participants in every competitive extracurricular activity. See Chandler, 520 U. S., at 319 (drug testing candidates for office held incompatible with Fourth Amendment because program was “not well designed to identify candidates who violate antidrug laws”).

Nationwide, students who participate in extracurricular activities are significantly less likely to develop substance abuse problems than are their less-involved peers. See, e. g., N. Zill, C. Nord, & L. Loomis, Adolescent Time Use, Risky Behavior, and Outcomes 52 (1995) (tenth graders “who reported spending no time in school-sponsored activities were ... 49 percent more likely to have used drugs” than those who spent 1-4 hours per week in such activities). Even if students might be deterred from drug use in order to preserve their extracurricular eligibility, it is at least as likely that other students might forgo their extracurricular involvement in order to avoid detection of their drug use. Tecumseh’s policy thus falls short doubly if deterrence is its aim: It invades the privacy of students who need deterrence least, and risks steering students at greatest risk for substance abuse away from extracurricular involvement that potentially may palliate drug problems.4

To summarize, this case resembles Vernonia only in that the School Districts in both cases conditioned engagement in activities outside the obligatory curriculum on random subjection to urinalysis. The defining characteristics of the two programs, however, are entirely dissimilar. The Vernonia district sought to test a subpopulation of students distinguished by their reduced expectation of privacy, their special *854susceptibility to drug-related injury, and their heavy involvement with drug use. The Tecumseh district seeks to test a much larger population associated with none of these factors. It does so, moreover, without carefully safeguarding student confidentiality and without regard to the program’s untoward effects. A program so sweeping is not sheltered by Vemonia; its unreasonable reach renders it impermissible under the Fourth Amendment.

II

In Chandler, this Court inspected “Georgias requirement that candidates for state office pass a drug test”; we held that the requirement “d[id] not fit within the closely guarded category of constitutionally permissible suspicion-less searches.” 520 U. S., at 309. Georgia’s testing prescription, the record showed, responded to no “concrete danger,” id., at 319, was supported by no evidence of a particular problem, and targeted a group not involved in “high-risk, safety-sensitive tasks,” id., at 321-322. We concluded:

“What is left, after close review of Georgia’s scheme, is the image the State seeks to project. By requiring candidates for public office to submit to drug testing, Georgia displays its commitment to the struggle against drug abuse.... The need revealed, in short, is symbolic, not ‘special,’ as that term draws meaning from our case law.” Ibid.

Close review of Tecumseh’s policy compels a similar conclusion. That policy was not shown to advance the “‘special needs’ [existing] in the public school context [to maintain]... swift and informal disciplinary procedures ... [and] order in the schools,” Vernonia, 515 U. S.,.at 653 (internal quotation marks omitted). See supra, at 846-848, 849-853. What is left is the School District’s undoubted purpose to heighten awareness of its abhorrence of, and strong stand against, drug abuse. But the desire to augment eommunica*855tion of this message does not trump the right of persons— even of children within the schoolhouse gate — to be “secure in their persons . . . against unreasonable searches and seizures.” U. S. Const., Arndt. 4.

In Chandler, the Court referred to a pathmarking dissenting opinion in which “Justice Brandéis recognized the importance of teaching by example: ‘Our Government is the potent, the omnipresent teacher. For good or for ill, it teaches the whole people by its example.’ ” 520 U. S., at 322 (quoting Olmstead v. United States, 277 U. S. 438, 485 (1928)). That wisdom should guide decisionmakers in the instant case: The government is nowhere more a teacher than when it runs a public school.

It is a sad irony that the petitioning School District seeks to justify its edict here by trumpeting “the schools’ custodial and tutelary responsibility for children.” Vernonia, 515 U. S., at 656. In regulating an athletic program or endeavoring to combat an exploding drug epidemic, a school’s custodial obligations may permit searches that would otherwise unacceptably abridge students’ rights. When custodial duties are not ascendant, however, schools’ tutelary obligations to their students require them to “teach by example” by avoiding symbolic measures that diminish constitutional protections. “That [schools] are educating the young for citizenship is reason for scrupulous protection of Constitutional freedoms of the individual, if we are not to strangle the free mind at its source and teach youth to discount important principles of our government as mere platitudes.” West Virginia Bd. of Ed. v. Barnette, 319 U. S. 624, 637 (1943).

* * *

For the reasons stated, I would affirm the judgment of the Tenth Circuit declaring the testing policy at issue unconstitutional.

*106Justice Souter

delivered the opinion of the Court.

The Fourth Amendment recognizes a valid warrantless entry and search of premises when police obtain the voluntary consent of an occupant who shares, or is reasonably believed to share, authority over the area in common with a co-occupant who later objects to the use of evidence so obtained. Illinois v. Rodriguez, 497 U. S. 177 (1990); United States v. Matlock, 415 U. S. 164 (1974). The question here is whether such an evidentiary seizure is likewise lawful with the permission of one occupant when the other, who later seeks to suppress the evidence, is present at the scene and expressly refuses to consent. We hold that, in the circumstances here at issue, a physically present co-occupant’s stated refusal to permit entry prevails, rendering the warrantless search unreasonable and invalid as to him.

I

Respondent Scott Randolph and his wife, Janet, separated in late May 2001, when she left the marital residence in Americus, Georgia, and went to stay with her parents in Canada, taking their son and some belongings. In July, she returned to the Americus house with the child, though the record does not reveal whether her object was reconciliation or retrieval of remaining possessions.

*107On the morning of July 6, she complained to the police that after a domestic dispute her husband took their son away, and when officers reached the house she told them that her husband was a cocaine user whose habit had caused financial troubles. She mentioned the marital problems, and said that she and their son had only recently returned after a stay of several weeks with her parents. Shortly after the police arrived, Scott Randolph returned and explained that he had removed the child to a neighbor’s house out of concern that his wife might take the boy out of the country again; he denied cocaine use, and countered that it was in fact his wife who abused drugs and alcohol.

One of the officers, Sergeant Murray, went with Janet Randolph to reclaim the child, and when they returned she not only renewed her complaints about her husband’s drug use, but also volunteered that there were “‘items of drug evidence’ ” in the house. Brief for Petitioner 3. Sergeant Murray asked Scott Randolph for permission to search the house, which he unequivocally refused.

The sergeant turned to Janet Randolph for consent to search, which she readily gave. She led the officer upstairs to a bedroom that she identified as Scott’s, where the sergeant noticed a section of a drinking straw with a powdery residue he suspected was cocaine. He then left the house to get an evidence bag from his car and to call the district attorney’s office, which instructed him to stop the search and apply for a warrant. When Sergeant Murray returned to the house, Janet Randolph withdrew her consent. The police took the straw to the police station, along with the Randolphs. After getting a search warrant, they returned to the house and seized further evidence of drug use, on the basis of which Scott Randolph was indicted for possession of cocaine.

He moved to suppress the evidence, as products of a warrantless search of his house unauthorized by his wife’s consent over his express refusal. The trial court denied the *108motion, ruling that Janet Randolph had common authority to consent to the search.

The Court of Appeals of Georgia reversed, 264 Ga. App. 396, 590 S. E. 2d 834 (2003), and was itself sustained by the State Supreme Court, principally on the ground that “the consent to conduct a warrantless search of a residence given by one occupant is not valid in the face of the refusal of another occupant who is physically present at the scene to permit a warrantless search,” 278 Ga. 614, 604 S. E. 2d 835, 836 (2004). The Supreme Court of Georgia acknowledged this Court’s holding in Matlock, 415 U. S. 164, that “the consent of one who possesses common authority over premises or effects is valid as against the absent, nonconsenting person with whom that authority is shared,” id., at 170, and found Matlock distinguishable just because Scott Randolph was not “absent” from the colloquy on which the police relied for consent to make the search. The State Supreme Court stressed that the officers in Matlock had not been “faced with the physical presence of joint occupants, with one consenting to the search and the other objecting.” 278 Ga., at 615, 604 S. E. 2d, at 837. It held that an individual who chooses to live with another assumes a risk no greater than “ 'an inability to control access to the premises during [his] absence,’” ibid, (quoting 3 W. LaFave, Search and Seizure § 8.3(d), p. 731 (3d ed. 1996) (hereinafter LaFave)), and does not contemplate that his objection to a request to search commonly shared premises, if made, will be overlooked.

We granted certiorari to resolve a split of authority on whether one occupant may give law enforcement effective consent to search shared premises, as against a co-tenant who is present and states a refusal to permit the search.1 544 U. S. 973 (2005). We now affirm.

*109II

To the Fourth Amendment rule ordinarily prohibiting the warrantless entry of a person’s house as unreasonable per se, Payton v. New York, 445 U. S. 573, 586 (1980); Coolidge v. New Hampshire, 403 U. S. 443, 454-455 (1971), one “jealously and carefully drawn” exception, Jones v. United States, 357 U. S. 493, 499 (1958), recognizes the validity of searches with the voluntary consent of an individual possessing authority, Rodriguez, 497 U. S., at 181. That person might be the householder against whom evidence is sought, Schneckloth v. Bustamonte, 412 U. S. 218, 222 (1973), or a fellow occupant who shares common authority over property, when the suspect is absent, Matlock, supra, at 170, and the exception for consent extends even to entries and searches with the permission of a co-occupant whom the police reasonably, but erroneously, believe to possess shared authority as an occupant, Rodriguez, supra, at 186. None of our co-occupant consent-to-search cases, however, has presented the further fact of a second occupant physically present and refusing permission to search, and later moving to suppress evidence so obtained.2 The significance of such a refusal turns on the underpinnings of the co-occupant consent rule, as recognized since Matlock.

A

The defendant in that case was arrested in the yard of a house where he lived with a Mrs. Graff and several of her *110relatives, and was detained in a squad ear parked nearby. When the police went to the door, Mrs. Graff admitted them and consented to a search of the house. 415 U. S., at 166. In resolving the defendant’s objection to use of the evidence taken in the warrantless search, we said that “the consent of one who possesses common authority over premises or effects is valid as against the absent, nonconsenting person with whom that authority is shared.” Id., at 170. Consistent with our prior understanding that Fourth Amendment rights are not limited by the law of property, cf. Katz v. United States, 389 U. S. 347, 352-353 (1967), we explained that the third party’s “common authority” is not synonymous with a technical property interest:

“The authority which justifies the third-party consent does not rest upon the law of property, with its attendant historical and legal refinements, but rests rather on mutual use of the property by persons generally having joint access or control for most purposes, so that it is reasonable to recognize that any of the co-inhabitants has the right to permit the inspection in his own right and that the others have assumed the risk that one of their number might permit the common area to be searched.” 415 U. S., at 171, n. 7 (citations omitted).

See also Frazier v. Cupp, 394 U. S. 731, 740 (1969) (“[I]n allowing [his cousin to share use of a duffel bag] and in leaving it in his house, [the suspect] must be taken to have assumed the risk that [the cousin] would allow someone else to look inside”). The common authority that counts under the Fourth Amendment may thus be broader than the rights accorded by property law, see Rodriguez, supra, at 181-182 (consent is sufficient when given by a person who reasonably appears to have common authority but who, in fact, has no property interest in the premises searched), although its limits, too, reflect specialized tenancy arrangements apparent to the police, see Chapman v. United States, 365 U. S. *111610 (1961) (landlord could not consent to search of tenant’s home).

The constant element in assessing Fourth Amendment reasonableness in the consent cases, then, is the great significance given to widely shared social expectations, which are naturally enough influenced by the law of property, but not controlled by its rules. Cf. Rakas v. Illinois, 439 U. S. 128, 144, n. 12 (1978) (an expectation of privacy is reasonable if it has “a source outside of the Fourth Amendment, either by reference to concepts of real or personal property law or to understandings that are recognized and permitted by society”). Matlock accordingly not only holds that a solitary co-inhabitant may sometimes consent to a search of shared premises, but stands for the proposition that the reasonableness of such a search is in significant part a function of commonly held understanding about the authority that co-inhabitants may exercise in ways that affect each other’s interests.

B

Matlock’s example of common understanding is readily apparent. When someone comes to the door of a domestic dwelling with a baby at her hip, as Mrs. Graff did, she shows that she belongs there, and that fact standing alone is enough to tell a law enforcement officer or any other visitor that if she occupies the place along with others, she probably lives there subject to the assumption tenants usually make about their common authority when they share quarters. They understand that any one of them may admit visitors, with the consequence that a guest obnoxious to one may nevertheless be admitted in his absence by another. As Matlock put it, shared tenancy is understood to include an “assumption of risk,” on which police officers are entitled to rely, and although some group living together might make an exceptional arrangement that no one could admit a guest without the agreement of all, the chance of such an eccentric scheme is too remote to expect visitors to investigate a particular *112household’s rules before accepting an invitation to come in. So, Matlock relied on what was usual and placed no burden on the police to eliminate the possibility of atypical arrangements, in the absence of reason to doubt that the regular scheme was in place.

It is also easy to imagine different facts on which, if known, no common authority could sensibly be suspected. A person on the scene who identifies himself, say, as a landlord or a hotel manager calls up no customary understanding of authority to admit guests without the consent of the current occupant. See Chapman v. United States, supra (landlord); Stoner v. California, 376 U. S. 483 (1964) (hotel manager). A tenant in the ordinary course does not take rented premises subject to any formal or informal agreement that the landlord may let visitors into the dwelling, Chapman, supra, at 617, and a hotel guest customarily has no reason to expect the manager to allow anyone but his own employees into his room, see Stoner, supra, at 489; see also United States v. Jeffers, 342 U. S. 48, 51 (1951) (hotel staff had access to room for purposes of cleaning and maintenance, but no authority to admit police). In these circumstances, neither state-law property rights, nor common contractual arrangements, nor any other source points to a common understanding of authority to admit third parties generally without the consent of a person occupying the premises. And when it comes to searching through bureau drawers, there will be instances in which even a person clearly belonging on premises as an occupant may lack any perceived authority to consent; “a child of eight might well be considered to have the power to consent to the police crossing the threshold into that part of the house where any caller, such as a pollster or salesman, might well be admitted,” 4 LaFave § 8.4(c), at 207 (4th ed. 2004), but no one would reasonably expect such a child to be in a position to authorize anyone to rummage through his parents’ bedroom.

*113c

Although we have not dealt directly with the reasonableness of police entry in reliance on consent by one occupant subject to immediate challenge by another, we took a step toward the issue in an earlier case dealing with the Fourth Amendment rights of a social guest arrested at premises the police entered without a warrant or the benefit of any exception to the warrant requirement. Minnesota v. Olson, 495 U. S. 91 (1990), held that overnight houseguests have a legitimate expectation of privacy in their temporary quarters because “it is unlikely that [the host] will admit someone who wants to see or meet with the guest over the objection of the guest,” id., at 99. If that customary expectation of courtesy or deference is a foundation of Fourth Amendment rights of a houseguest, it presumably should follow that an inhabitant of shared premises may claim at least as much, and it turns out that the co-inhabitant naturally has an even stronger claim.

To begin with, it is fair to say that a caller standing at the door of shared premises would have no confidence that one occupant’s invitation was a sufficiently good reason to enter when a fellow tenant stood there saying, “stay out.” Without some very good reason, no sensible person would go inside under those conditions. Fear for the safety of the occupant issuing the invitation, or of someone else inside, would be thought to justify entry, but the justification then would be the personal risk, the threats to life or limb, not the disputed invitation.3

The visitor’s reticence without some such good reason would show not timidity but a realization that when people living together disagree over the use of their common quar*114ters, a resolution must come through voluntary accommodation , not by appeals to authority. Unless the people living together fall within some recognized hierarchy, like a household of parent and child or barracks housing military personnel of different grades, there is no societal understanding of superior and inferior, a fact reflected in a standard formulation of domestic property law, that “[e]ach cotenant . . . has the right to use and enjoy the entire property as if he or she were the sole owner, limited only by the same right in the other cotenants.” 7 R. Powell, Powell on Real Property § 50.03[1], p. 50-14 (M. Wolf gen. ed. 2005). The want of any recognized superior authority among disagreeing tenants is also reflected in the law’s response when the disagreements cannot be resolved. The law does not ask who has the better side of the conflict; it simply provides a right to any co-tenant, even the most unreasonable, to obtain a decree partitioning the property (when the relationship is one of co-ownership) and terminating the relationship. See, e. g., 2 H. Tiffany, Real Property §§468, 473, 474, pp. 297, 307-309 (3d ed. 1939 and 2006 Cum. Supp.). And while a decree of partition is not the answer to disagreement among rental tenants, this situation resembles co-ownership in lacking the benefit of any understanding that one or the other rental co-tenant has a superior claim to control the use of the quarters they occupy together. In sum, there is no common understanding that one co-tenant generally has a right or authority to prevail over the express wishes of another, whether the issue is the color of the curtains or invitations to outsiders.

D

Since the co-tenant wishing to open the door to a third party has no recognized authority in law or social practice to prevail over a present and objecting co-tenant, his disputed invitation, without more, gives a police officer no better claim to reasonableness in entering than the officer would have in the absence of any consent at all. Accordingly, in the bal*115ancing of competing individual and governmental interests entailed by the bar to unreasonable searches, Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523, 536-537 (1967), the cooperative occupant’s invitation adds nothing to the government’s side to counter the force of an objecting individual’s claim to security against the government’s intrusion into his dwelling place. Since we hold to the “centuries-old principle of respect for the privacy of the home,” Wilson v. Layne, 526 U. S. 603, 610 (1999), “it is beyond dispute that the home is entitled to special protection as the center of the private lives of our people,” Minnesota v. Carter, 525 U. S. 83, 99 (1998) (Kennedy, J., concurring). We have, after all, lived our whole national history with an understanding of “the ancient adage that a man’s house is his castle [to the point that t]he poorest man may in his cottage bid defiance to all the forces of the Crown,” Miller v. United States, 357 U. S. 301, 307 (1958) (internal quotation marks omitted).4

Disputed permission is thus no match for this central value of the Fourth Amendment, and the State’s other countervailing claims do not add up to outweigh it.5 Yes, we recognize the consenting tenant’s interest as a citizen in bringing crim*116inal activity to light, see Coolidge, 403 U. S., at 488 (“[I]t is no part of the policy underlying the Fourth :.. Amendment] to discourage citizens from aiding to the utmost of their ability in the apprehension of criminals”). And we understand a co-tenant’s legitimate self-interest in siding with the police to deflect suspicion raised by sharing quarters with a criminal, see 4 LaFave § 8.3(d), at 162, n. 72 (“The risk of being convicted of possession of drugs one knows are present and has tried to get the other occupant to remove is by no means insignificant”); cf. Schneckloth, 412 U. S., at 243 (evidence obtained pursuant to a consent search “may insure that a wholly innocent person is not wrongly charged with a criminal offense”).

But society can often have the benefit of these interests without relying on a theory of consent that ignores an inhabitant’s refusal to allow a warrantless search. The co-tenant acting on his own initiative may be able to deliver evidence to the police, Coolidge, supra, at 487-489 (suspect’s wife retrieved his guns from the couple’s house and turned them over to the police), and can tell the police what he knows, for use before a magistrate in getting a warrant.6 The reliance *117on a co-tenant’s information instead of disputed consent accords with the law’s general partiality toward “police action taken under a warrant [as against] searches and seizures without one,” United States v. Ventresca, 380 U. S. 102, 107 (1965); “the informed and deliberate determinations of magistrates empowered to issue warrants as to what searches and seizures are permissible under the Constitution are to be preferred over the hurried action of officers,” United States v. Lefkowitz, 285 U. S. 452, 464 (1932).

Nor should this established policy of Fourth Amendment law be undermined by the principal dissent’s claim that it shields spousal abusers and other violent co-tenants who will refuse to allow the police to enter a dwelling when their victims ask the police for help, post, at 138 (opinion of RobEETS, C. J.) (hereinafter the dissent). It is not that the dissent exaggerates violence in the home; we recognize that domestic abuse is a serious problem in the United States. See U. S. Dept, of Justice, National Institute of Justice, P. Tjaden & N. Thoennes, Full Report of the Prevalence, Incidence, and Consequences of Violence Against Women 25-26 (2000) (noting that over 20 million women and 6 million men will, in the course of their lifetimes, be the victims of intimate-partner abuse); U. S. Dept, of Health and Human Services, Centers for Disease Control and Prevention, National Center for Injury Prevention and Control, Costs of Intimate Partner Violence Against Women in the United States 19 (2003) (finding that nearly 5.3 million intimate-partner victimizations, which result in close to 2 million injuries and 1,300 deaths, occur among women in the United States each year); U. S. Dept, of Justice, Bureau of Justice Statistics, Crime Data Brief, C. Rennison, Intimate Partner Violence, 1993-2001 (Feb. 2003) (noting that in 2001 intimate-partner violence made up 20% of violent crime against women); see also Becker, The Politics of Women’s *118Wrongs and the Bill of “Rights”: A Bicentennial Perspective, 59 U. Chi. L. Rev. 453, 507-508 (1992) (noting that women may feel physical insecurity in their homes as a result of abuse from domestic partners).

But this case has no bearing on the capacity of the police to protect domestic victims. The dissent’s argument rests on the failure to distinguish two different issues: when the police may enter without committing a trespass, and when the police may enter to search for evidence. No question has been raised, or reasonably could be, about the authority of the police to enter a dwelling to protect a resident from domestic violence; so long as they have good reason to believe such a threat exists, it would be silly to suggest that the police would commit a tort by entering, say, to give a complaining tenant the opportunity to collect belongings and get out safely, or to determine whether violence (or threat of violence) has just occurred or is about to (or soon will) occur, however much a spouse or other co-tenant objected. (And since the police would then be lawfully in the premises, there is no question that they could seize any evidence in plain view or take further action supported by any consequent probable cause, see Texas v. Brown, 460 U. S. 730, 737-739 (1983) (plurality opinion).) Thus, the question whether the police might lawfully enter over objection in order to provide any protection that might be reasonable is easily answered yes. See 4 LaFave § 8.3(d), at 161 (“[E]ven when . . . two persons quite clearly have equal rights in the place, as where two individuals are sharing an apartment on an equal basis, there may nonetheless sometimes exist a basis for giving greater recognition to the interests of one over the other.... [W]here the defendant has victimized the third-party ... the emergency nature of the situation is such that the third-party consent should validate a warrantless search despite defendant’s objections” (internal quotation marks omitted; third omission in original)). The undoubted right of the po*119lice to enter in order to protect a victim, however, has nothing to do with the question in this case, whether a search with the consent of one co-tenant is good against another, standing at the door and expressly refusing consent.7

None of the cases cited by the dissent support its improbable view that recognizing limits on merely evidentiary searches would compromise the capacity to protect a fearful occupant. In the circumstances of those cases, there is no danger that the fearful occupant will be kept behind the closed door of the house simply because the abusive tenant refuses to consent to a search. See United States v. Donlin, 982 F. 2d 31, 32 (CA1 1992) (victimized individual was already outside of her apartment when police arrived and, for all intents and purposes, within the protective custody of law enforcement officers); United States v. Hendrix, 595 F. 2d 883, 885-886 (CADC 1979) (per curiam) (even if the consent of the threatened co-occupant did not justify a warrantless search, the police entry was nevertheless allowable on exigent circumstances grounds); People v. Sanders, 904 P. 2d 1311, 1313-1315 (Colo. 1995) (en banc) (victimized individual gave her consent to search away from her home and was not present at the time of the police visit; alternatively, exigent circumstances existed to satisfy the warrantless exception); Brandon v. State, 778 P. 2d 221, 223-224 (Alaska App. 1989) (victimized individual consented away from her home and was not present at the time of the police visit); United States v. Davis, 290 F. 3d 1239, 1241 (CA10 2002) (immediate harm extinguished after husband “order[ed]” wife out of the home).

*120The dissent’s red herring aside, we know, of course, that alternatives to disputed consent will not always open the door to search for evidence that the police suspect is inside. The consenting tenant may simply not disclose enough information, or information factual enough, to add up to a showing of probable cause, and there may be no exigency to justify fast action. But nothing in social custom or its reflection in private law argues for placing a higher value on delving into private premises to search for evidence in the face of disputed consent, than on requiring clear justification before the government searches private living quarters over a resident’s objection. We therefore hold that a warrantless search of a shared dwelling for evidence over the express refusal of consent by a physically present resident cannot be justified as reasonable as to him on the basis of consent given to the police by another resident.8

E

There are two loose ends, the first being the explanation given in Matlock for the constitutional sufficiency of a co-tenant’s consent to enter and search: it “rests ... on mutual use of the property by persons generally having joint access or control for most purposes, so that it is reasonable to recognize that any of the co-inhabitants has the right to permit the inspection in his own right... .” 415 U. S., at 171, n. 7. If Matlock’s co-tenant is giving permission “in his own right,” how can his “own right” be eliminated by another tenant’s objection? The answer appears in the very footnote from which the quoted statement is taken: the “right” to admit the police to which Matlock refers is not an enduring and enforceable ownership right as understood by the *121private law of property, but is instead the authority recognized by customary social usage as having a substantial bearing on Fourth Amendment reasonableness in specific circumstances. Thus, to ask whether the consenting tenant has the right to admit the police when a physically present fellow tenant objects is not to question whether some property right may be divested by the mere objection of another. It is, rather, the question whether customary social understanding accords the consenting tenant authority powerful enough to prevail over the co-tenant’s objection. The Matlock Court did not purport to answer this question, a point made clear by another statement (which the dissent does not quote): the Court described the co-tenant’s consent as good against “the absent, nonconsenting” resident. Id., at 170.

The second loose end is the significance of Matlock and Rodriguez after today’s decision. Although the Matlock defendant was not present with the opportunity to object, he was in a squad car not far away; the Rodriguez defendant was actually asleep in the apartment, and the police might have roused him with a knock on the door before they entered with only the consent of an apparent co-tenant. If those cases are not to be undercut by today’s holding, we have to admit that we are drawing a fine line; if a potential defendant with self-interest in objecting is in fact at the door and objects, the co-tenant’s permission does not suffice for a reasonable search, whereas the potential objector, nearby but not invited to take part in the threshold colloquy, loses out.

This is the line we draw, and we think the formalism is justified. So long as there is no evidence that the police have removed the potentially objecting tenant from the entrance for the sake of avoiding a possible objection, there is practical value in the simple clarity of complementary rules, one recognizing the co-tenant’s permission when there is no fellow occupant on hand, the other according dispositive weight to the fellow occupant’s contrary indication when he *122expresses it. For the very reason that Rodriguez held it would be unjustifiably impractical to require the police to take affirmative steps to confirm the actual authority of a consenting individual whose authority was apparent, we think it would needlessly limit the capacity of the police to respond to ostensibly legitimate opportunities in the field if we were to hold that reasonableness required the police to take affirmative steps to find a potentially objecting co-tenant before acting on the permission they had already received. There is no ready reason to believe that efforts to invite a refusal would make a difference in many cases, whereas every co-tenant consent case would turn into a test about the adequacy of the police’s efforts to consult with a potential objector. Better to accept the formalism of distinguishing Matlock from this case than to impose a requirement, time consuming in the field and in the courtroom, with no apparent systemic justification. The pragmatic decision to accept the simplicity of this line is, moreover, supported by the substantial number of instances in which suspects who are asked for permission to search actually consent,9 albeit imprudently, a fact that undercuts any argument that the police should try to locate a suspected inhabitant because his denial of consent would be a foregone conclusion.

Ill

This case invites a straightforward application of the rule that a physically present inhabitant’s express refusal of consent to a police search is dispositive as to him, regardless of *123the consent of a fellow occupant. Scott Randolph’s refusal is clear, and nothing in the record justifies the search on grounds independent of Janet Randolph’s consent. The State does not argue that she gave any indication to the police of a need for protection inside the house that might have justified entry into the portion of the premises where the police found the powdery straw (which, if lawfully seized, could have been used when attempting to establish probable cause for the warrant issued later). Nor does the State claim that the entry and search should be upheld under the rubric of exigent circumstances, owing to some apprehension by the police officers that Scott Randolph would destroy evidence of drug use before any warrant could be obtained.

The judgment of the Supreme Court of Georgia is therefore affirmed.

It is so ordered.

Justice Alito took no part in the consideration or decision of this case.

Justice Stevens,

concurring.

The study of history for the purpose of ascertaining the original understanding of constitutional provisions is much like the study of legislative history for the purpose of ascertaining the intent of the lawmakers who enact statutes. In both situations the facts uncovered by the study are usually relevant but not necessarily dispositive. This case illustrates why even the most dedicated adherent to an approach to constitutional interpretation that places primary reliance on the search for original understanding would recognize the relevance of changes in our society.

At least since 1604 it has been settled that in the absence of exigent circumstances, a government agent has no right to enter a “house” or “castle” unless authorized to do so by a valid warrant. See Semayne’s Case, 5 Co. Rep. 91a, 77 Eng. Rep. 194 (K. B.). Every occupant of the home has a *124right — protected by the common law for centuries and by the Fourth Amendment since 1791 — to refuse entry. When an occupant gives his or her consent to enter, he or she is waiving a valuable constitutional right. To be sure that the waiver is voluntary, it is sound practice — a practice some Justices of this Court thought necessary to make the waiver voluntary1 — for the officer to advise the occupant of that right.2 The issue in this case relates to the content of the advice that the officer should provide when met at the door by a man and a woman who are apparently joint tenants or joint owners of the property.

In the 18th century, when the Fourth Amendment was adopted, the advice would have been quite different from what is appropriate today. Given the then-prevailing dramatic differences between the property rights of the husband and the far lesser rights of the wife, only the consent of the husband would matter. Whether “the master of the house” consented or objected, his decision would control. Thus if “original understanding” were to govern the outcome of this case, the search was clearly invalid because the husband did not consent. History, however, is not dispositive because it is now clear, as a matter of constitutional law, that *125the male and the female are equal partners. Reed v. Reed, 404 U. S. 71 (1971).

In today’s world the only advice that an officer could properly give should make it clear that each of the partners has a constitutional right that he or she may independently assert or waive. Assuming that both spouses are competent, neither one is a master possessing the power to override the other’s constitutional right to deny entry to their castle.

With these observations, I join the Court’s opinion.

Justice Breyer,

concurring.

If Fourth Amendment law forced us to choose between two bright-line rules, (1) a rule that always found one tenant’s consent sufficient to justify a search without a warrant and (2) a rule that never did, I believe we should choose the first. That is because, as The Chief Justice’s dissent points out, a rule permitting such searches can serve important law enforcement needs (for example, in domestic abuse cases), and the consenting party’s joint tenancy diminishes the objecting party’s reasonable expectation of privacy.

But the Fourth Amendment does not insist upon bright-line rules. Rather, it recognizes that no single set of legal rules can capture the ever-changing complexity of human life. It consequently uses the general terms “unreasonable searches and seizures.” And this Court has continuously emphasized that “Reasonableness ... is measured . . . by examining the totality of the circumstances.” Ohio v. Robinette, 519 U. S. 33, 39 (1996); see also Illinois v. Wardlow, 528 U. S. 119, 136 (2000) (Stevens, J., concurring in part and dissenting in part); Florida v. Bostick, 501 U. S. 429, 439 (1991); Michigan v. Chesternut, 486 U. S. 567, 572-573 (1988); Florida v. Royer, 460 U. S. 491, 506 (1983) (plurality opinion).

The circumstances here include the following: The search at issue was a search solely for evidence. The objecting *126party was present and made his objection known clearly and directly to the officers seeking to enter the house. The officers did not justify their search on grounds of possible evidence destruction. Cf. Thornton v. United States, 541 U. S. 615, 620-622 (2004); Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602, 623 (1989); Schmerber v. California, 384 U. S. 757, 770-771 (1966). And, as far as the record reveals, the officers might easily have secured the premises and sought a warrant permitting them to enter. See Illinois v. McArthur, 531 U. S. 326 (2001). Thus, the “totality of the circumstances” present here do not suffice to justify abandoning the Fourth Amendment’s traditional hostility to police entry into a home without a warrant.

I stress the totality of the circumstances, however, because, were the circumstances to change significantly, so should the result. The Court’s opinion does not apply where the objector is not present “and objecting].” Ante, at 121.

Moreover, the risk of an ongoing crime or other exigent circumstance can make a critical difference. Consider, for example, instances of domestic abuse. See ante, at 117-118. “Family disturbance calls . . . constitute the largest single category of calls received by police departments each year.” Mederer & Gelles, Compassion or Control: Intervention in Cases of Wife Abuse, 4 J. of Interpersonal Violence 25 (Mar. 1989) (emphasis deleted); see also, e. g., Office of the Attorney General, California Criminal Justice Statistics Center, Domestic Violence Related Calls for Assistance, 1987-2003, County by Year, http://ag.ca.gov/cjsc/publications/misc/ dvsr/tabs/ 8703.pdf (as visited Mar. 1, 2006, and available in Clerk of Court’s case file) (providing data showing that California police received an average of 207,848 domestic violence related calls each year); Cessato, Defenders Against Domestic Abuse, Washington Post, Aug. 25, 2002, p. B8 (“In the District [of Columbia], police report that almost half of roughly 39,000 violent crime calls received in 2000 involved domestic violence”); Zorza, Women Battering: High Costs *127and the State of the Law, Clearinghouse Review 383, 385 (Special Issue 1994) (“One-third of all police time is spent responding to domestic disturbance calls”). And, law enforcement officers must be able to respond effectively when confronted with the possibility of abuse.

If a possible abuse victim invites a responding officer to enter a home or consents to the officer’s entry request, that invitation (or consent) itself could reflect the victim’s fear about being left alone with an abuser. It could also indicate the availability of evidence, in the form of an immediate willingness to speak, that might not otherwise exist. In that context, an invitation (or consent) would provide a special reason for immediate, rather than later, police entry. And, entry following invitation or consent by one party ordinarily would be reasonable even in the face of direct objection by the other. That being so, contrary to The Chief Justice’s suggestion, post, at 139, today’s decision will not adversely affect ordinary law enforcement practices.

Given the case-specific nature of the Court’s holding, and with these understandings, I join the Court’s holding and its opinion.

Chief Justice Roberts,

with whom

Justice Scalia joins, dissenting.

The Court creates constitutional law by surmising what is typical when a social guest encounters an entirely atypical situation. The rule the majority fashions does not implement the high office of the Fourth Amendment to protect privacy, but instead provides protection on a random and happenstance basis, protecting, for example, a co-occupant who happens to be at the front door when the other occupant consents to a search, but not one napping or watching television in the next room. And the cost of affording such random protection is great, as demonstrated by the recurring cases in which abused spouses seek to authorize police entry into a home they share with a nonconsenting abuser.

*128The correct approach to the question presented is clearly mapped out in our precedents: The Fourth Amendment protects privacy. If an individual shares information, papers, or places with another, he assumes the risk that the other person will in turn share access to that information or those papers or places with the government. And just as an individual who has shared illegal plans or incriminating documents with another cannot interpose an objection when that other person turns the information over to the government, just because the individual happens to be present at the time, so too someone who shares a place with another cannot interpose an objection when that person decides to grant access to the police, simply because the objecting individual happens to be present.

A warrantless search is reasonable if police obtain the voluntary consent of a person authorized to give it. Co-occupants have “assumed the risk that one of their number might permit [a] common area to be searched.” United States v. Matlock, 415 U. S. 164, 171, n. 7 (1974). Just as Mrs. Randolph could walk upstairs, come down, and turn her husband’s cocaine straw over to the police, she can consent to police entry and search of what is, after all, her home, too.

I

In Illinois v. Rodriguez, 497 U. S. 177 (1990), this Court stated that “[w]hat [a person] is assured by the Fourth Amendment ... is not that no government search of his house will occur unless he consents; but that no such search will occur that is ‘unreasonable.’” Id., at 183. One element that can make a warrantless government search of a home “‘reasonable’” is voluntary consent. Id., at 184; Schneckloth v. Bustamonte, 412 U. S. 218, 219 (1973). Proof of voluntary consent “is not limited to proof that consent was given by the defendant,” but the government “may show that permission to search was obtained from a third party who possessed common authority over or other sufficient re*129lationship to the premises.” Matlock, supra, at 171. Today’s opinion creates an exception to this otherwise clear rule: A third-party consent search is unreasonable, and therefore constitutionally impermissible, if the co-occupant against whom evidence is obtained was present and objected to the entry and search.

This exception is based on what the majority describes as “widely shared social expectations” that “when people living together disagree over the use of their common quarters, a resolution must come through voluntary accommodation.” Ante, at 111, 113-114. But this fundamental predicate to the majority’s analysis gets us nowhere: Does the objecting co-tenant accede to the consenting co-tenant’s wishes, or the other way around? The majority’s assumption about voluntary accommodation simply leads to the common stalemate of two gentlemen insisting that the other enter a room first.

Nevertheless, the majority is confident in assuming — confident enough to incorporate its assumption into the Constitution — that an invited social guest who arrives at the door of a shared residence, and is greeted by a disagreeable co-occupant shouting “‘stay out,’” would simply go away. Ante, at 113. The Court observes that “no sensible person would go inside under those conditions,” ibid., and concludes from this that the inviting co-occupant has no “authority” to insist on getting her way over the wishes of her co-occupant, ante, at 114. But it seems equally accurate to say — based on the majority’s conclusion that one does not have a right to prevail over the express wishes of his co-occupant — that the objector has no “authority” to insist on getting his way over his co-occupant’s wish that her guest be admitted.

The fact is that a wide variety of differing social situations can readily be imagined, giving rise to quite different social expectations. A relative or good friend of one of two feuding roommates might well enter the apartment over the objection of the other roommate. The reason the invitee *130appeared at the door also affects expectations: A guest who came to celebrate an occupant’s birthday, or one who had traveled some distance for a particular reason, might not readily turn away simply because of a roommate’s objection. The nature of the place itself is also pertinent: Invitees may react one way if the feuding roommates share one room, differently if there are common areas from which the objecting roommate could readily be expected to absent himself. Altering the numbers might well change the social expectations: Invitees might enter if two of three co-occupants encourage them to do so, over one dissenter.

The possible scenarios are limitless, and slight variations in the fact pattern yield vastly different expectations about whether the invitee might be expected to enter or to go away. Such shifting expectations are not a promising foundation on which to ground a constitutional rule, particularly because the majority has no support for its basic assumption — that an invited guest encountering two disagreeing co-occupants would flee — beyond a hunch about how people would typically act in an atypical situation.

And in fact the Court has not looked to such expectations to decide questions of consent under the Fourth Amendment, but only to determine when a search has occurred and whether a particular person has standing to object to a search. For these latter inquiries, we ask whether a person has a subjective expectation of privacy in a particular place, and whether “the expectation [is] one that society is prepared to recognize as ‘reasonable.’” Katz v. United States, 389 U. S. 347, 361 (1967) (Harlan, J., concurring); see Minnesota v. Olson, 495 U. S. 91, 95-96, 100 (1990) (extending Katz test to standing inquiry). But the social expectations concept has not been applied to all questions arising under the Fourth Amendment, least of all issues of consent. A criminal might have a strong expectation that his longtime confidant will not allow the government to listen to their private conversations, but however profound his shock might be *131upon betrayal, government monitoring with the confidant’s consent is reasonable under the Fourth Amendment. See United States v. White, 401 U. S. 745, 752 (1971) (plurality opinion).

The majority suggests that “widely shared social expectations” are a “constant element in assessing Fourth Amendment reasonableness,” ante, at 111 (citing Rakas v. Illinois, 439 U. S. 128, 144, n. 12 (1978)), but that is not the case; the Fourth Amendment precedents the majority cites refer instead to a “legitimate expectation of privacy,” id., at 143, n. 12 (emphasis added; internal quotation marks omitted). Whatever social expectation the majority seeks to protect, it is not one of privacy. The very predicate giving rise to the question in cases of shared information, papers, containers, or places is that privacy has been shared with another. Our common social expectations may well be that the other person will not, in turn, share what we have shared with them with another — including the police — but that is the risk we take in sharing. If two friends share a locker and one keeps contraband inside, he might trust that his friend will not let others look inside. But by sharing private space, privacy has “already been frustrated” with respect to the locker-mate. United States v. Jacobsen, 466 U. S. 109, 117 (1984). If two roommates share a computer and one keeps pirated software on a shared drive, he might assume that his roommate will not inform the government. But that person has given up his privacy with respect to his roommate by saving the software on their shared computer.

A wide variety of often subtle social conventions may shape expectations about how we act when another shares with us what is otherwise private, and those conventions go by a variety of labels — courtesy, good manners, custom, protocol, even honor among thieves. The Constitution, however, protects not these but privacy, and once privacy has been shared, the shared information, documents, or places remain private only at the discretion of the confidant.

*132II

Our cases reflect this understanding. In United States v. White, we held that one party to a conversation can consent to government eavesdropping, and statements made by the other party will be admissible at trial. 401 U. S., at 752. This rule is based on privacy: “Inescapably, one contemplating illegal activities must realize and risk that his companions may be reporting to the police.... [I]f he has no doubts, or allays them, or risks what doubt he has, the risk is his.” Ibid.

The Court has applied this same analysis to objects and places as well. In Frazier v. Cupp, 394 U. S. 731 (1969), a duffel bag “was being used jointly” by two cousins. Id., at 740. The Court held that the consent of one was effective to result in the seizure of evidence used against both: “[I]n allowing [his cousin] to use the bag and in leaving it in his house, [the defendant] must be taken to have assumed the risk that [his cousin] would allow someone else to look inside.” Ibid.

As the Court explained in United States v. Jacobsen, supra:

“It is well settled that when an individual reveals private information to another, he assumes the risk that his confidant will reveal that information to the authorities, and if that occurs the Fourth Amendment does not prohibit governmental use of that information. Once frustration of the original expectation of privacy occurs, the Fourth Amendment does not prohibit governmental use of the now nonprivate information: ‘This Court has held repeatedly that the Fourth Amendment does not prohibit the obtaining of information revealed to a third party and conveyed by him to Government authorities, even if the information is revealed on the assumption that it will be used only for a limited purpose and the confidence placed in a third party will not be betrayed.’ ” *133Id., at 117 (quoting United States v. Miller, 425 U. S. 435, 443 (1976)).

The same analysis applies to the question whether our privacy can be compromised by those with whom we share common living space. If a person keeps contraband in common areas of his home, he runs the risk that his co-occupants will deliver the contraband to the police. In Coolidge v. New Hampshire, 403 U. S. 443 (1971), Mrs. Coolidge retrieved four of her husband’s guns and the clothes he was wearing the previous night and handed them over to police. We held that these items were properly admitted at trial because “when Mrs. Coolidge of her own accord produced the guns and clothes for inspection, ... it was not incumbent on the police to stop her or avert their eyes.” Id., at 489.

Even in our most private relationships, our observable actions and possessions are private at the discretion of those around us. A husband can request that his wife not tell a jury about contraband that she observed in their home or illegal activity to which she bore witness, but it is she who decides whether to invoke the testimonial marital privilege. Trammel v. United States, 445 U. S. 40, 53 (1980). In Trammel, we noted that the former rule prohibiting a wife from testifying about her husband’s observable wrongdoing at his say-so “goes far beyond making ‘every man’s house his castle,’ and permits a person to convert his house into ‘a den of thieves.’” Id., at 51-52 (quoting 5 J. Bentham, Rationale of Judicial Evidence 340 (1827)).

There is no basis for evaluating physical searches of shared space in a manner different from how we evaluated the privacy interests in the foregoing cases, and in fact the Court has proceeded along the same lines in considering such searches. In Matlock, police arrested the defendant in the front yard of a house and placed him in a squad car, and then obtained permission from Mrs. Graff to search a shared bedroom for evidence of Matlock’s bank robbery. 415 U. S., at 166. Police certainly could have assumed that Matlock *134would have objected were he consulted as he sat handcuffed in the squad car outside. And in Rodriguez, where Miss Fischer offered to facilitate the arrest of her sleeping boyfriend by admitting police into an apartment she apparently shared with him, 497 U. S., at 179, police might have noted that this entry was undoubtedly contrary to Rodriguez’s social expectations. Yet both of these searches were reasonable under the Fourth Amendment because Mrs. Graff had authority, and Miss Fischer apparent authority, to admit others into areas over which they exercised control, despite the almost certain wishes of their present co-occupants.

The common thread in our decisions upholding searches conducted pursuant to third-party consent is an understanding that a person “assume[s] the risk” that those who have access to and control over his shared property might consent to a search. Matlock, 415 U. S., at 171, n. 7. In Matlock, we explained that this assumption of risk is derived from a third party’s “joint access or control for most purposes” of shared property. Ibid. And we concluded that shared use of property makes it “reasonable to recognize that any of the co-inhabitants has the right to permit the inspection in his own right.” Ibid.

In this sense, the risk assumed by a joint occupant is comparable to the risk assumed by one who reveals private information to another. If a person has incriminating information, he can keep it private in the face of a request from police to share it, because he has that right under the Fifth Amendment. If a person occupies a house with incriminating information in it, he can keep that information private in the face of a request from police to search the house, because he has that right under the Fourth Amendment. But if he shares the information — or the house — with another, that other can grant access to the police in each instance.1

*135To the extent a person wants to ensure that his possessions will be subject to a consent search only due' to his own consent, he is free to place these items in an area over which others do not share access and control, be it a private room or a locked suitcase under a bed. Mr. Randolph acknowledged this distinction in his motion to suppress, where he differentiated his law office from the rest of the Randolph house by describing it as an area that “was solely in his control and dominion.” App. 3. As to a “common area,” however, co-occupants with “joint access or control” may consent to an entry and search. Matlock, supra, at 171, n. 7.

By emphasizing the objector’s presence and noting an occupant’s understanding that obnoxious guests might “be admitted in [one’s] absence,” ante, at 111, the majority appears to resurrect an agency theory of consent suggested in our early cases. See Stoner v. California, 376 U. S. 483, 489 (1964) (stating that a hotel clerk could not consent to a search of a guest’s room because the guest had not waived his rights *136“by word or deed, either directly or through an agent”); Chapman v. United States, 365 U. S. 610, 616-617 (1961). This agency theory is belied by the facts of Matlock and Rodriguez — both defendants were present but simply not asked for consent — and the Court made clear in those cases that a co-occupant’s authority to consent rested not on an absent occupant’s delegation of choice to an agent, but on the consenting co-occupant’s “joint access or control” of the property. Matlock, supra, at 171, n. 7; see Rodriguez, supra, at 181; United States v. McAlpine, 919 F. 2d 1461, 1464, n. 2 (CA10 1990) (“[A]gency analysis [was] put to rest by the Supreme Court’s reasoning in Matlock”).

The law acknowledges that although we might not expect our friends and family to admit the government into common areas, sharing space entails risk. A person assumes the risk that his co-occupants — just as they might report his illegal activity or deliver his contraband to the government — might consent to a search of areas over which they have access and control. See United States v. Karo, 468 U. S. 705, 726 (1984) (O’Connor, J., concurring in part and concurring in judgment) (finding it a “relatively easy case ... when two persons share identical, overlapping privacy interests in a particular place, container, or conversation. Here both share the power to surrender each other’s privacy to a third party”).

Ill

The majority states its rule as follows: “[A] warrantless search of a shared dwelling for evidence over the express refusal of consent by a physically present resident cannot be justified as reasonable as to him on the basis of consent given to the police by another resident.” Ante, at 120.

Just as the source of the majority’s rule is not privacy, so too the interest it protects cannot reasonably be described as such. That interest is not protected if a co-owner happens to be absent when the police arrive, in the backyard gardening, asleep in the next room, or listening to music *137through earphones so that only his co-occupant hears the knock on the door. That the rule is so random in its application confirms that it bears no real relation to the privacy protected by the Fourth Amendment. What the majority’s rule protects is not so much privacy as the good luck of a co-owner who just happens to be present at the door when the police arrive. Usually when the development of Fourth Amendment jurisprudence leads to such arbitrary lines, we take it as a signal that the rules need to be rethought. See California v. Acevedo, 500 U. S. 565, 574, 580 (1991). We should not embrace a rule at the outset that its sponsors appreciate will result in drawing fine, formalistic lines. See ante, at 121.

Rather than draw such random and happenstance lines— and pretend that the Constitution decreed them — the more reasonable approach is to adopt a rule acknowledging that shared living space entails a limited yielding of privacy to others, and that the law historically permits those to whom we have yielded our privacy to in turn cooperate with the government. Such a rule flows more naturally from our casés concerning Fourth Amendment reasonableness and is logically grounded in the concept of privacy underlying that Amendment.

The scope of the majority’s rule is not only arbitrary but obscure as well. The majority repeats several times that a present co-occupant’s refusal to permit entry renders the search unreasonable and invalid “as to him.” Ante, at 106, 120, 122. This implies entry and search would be reasonable “as to” someone else, presumably the consenting co-occupant and any other absent co-occupants. The normal Fourth Amendment rule is that items discovered in plain view are admissible if the officers were legitimately on the premises; if the entry and search were reasonable “as to” Mrs. Randolph, based on her consent, it is not clear why the cocaine straw should not be admissible “as to” Mr. Randolph, as discovered in plain view during a legitimate search “as *138to” Mrs. Randolph. The majority’s differentiation between entry focused on discovering whether domestic violence has occurred (and the consequent authority to seize items in plain view), and entry focused on searching for evidence of other crime, is equally puzzling. See ante, at 118-119. This Court has rejected subjective motivations of police officers in assessing Fourth Amendment questions, see Whren v. United States, 517 U. S. 806, 812-813 (1996), with good reason: The police do not need a particular reason to ask for consent to search, whether for signs of domestic violence or evidence of drug possession.

While the majority’s rule protects something random, its consequences are particularly severe. The question presented often arises when innocent co-tenants seek to disassociate or protect themselves from ongoing criminal activity. See, e. g., United States v. Hendrix, 595 F. 2d 883, 884 (CADC 1979) (per curiam) (wife asked police “ ‘to get her baby and take [a] sawed-off shotgun out of her house’”); People v. Cosme, 48 N. Y. 2d 286, 288-289, 293, 397 N. E. 2d 1319, 1320, 1323 (1979) (woman asked police to remove cocaine and a gun from a shared closet); United States v. Botsch, 364 F. 2d 542, 547 (CA2 1966). Under the majority’s rule, there will be many cases in which a consenting co-occupant’s wish to have the police enter is overridden by an objection from another present co-occupant. What does the majority imagine will happen, in a case in which the consenting co-occupant is concerned about the other’s criminal activity, once the door clicks shut? The objecting co-occupant may pause briefly to decide whether to destroy any evidence of wrongdoing or to inflict retribution on the consenting co-occupant first, but there can be little doubt that he will attend to both in short order. It is no answer to say that the consenting co-occupant can depart with the police; remember that it is her home, too, and the other co-occupant’s very presence, which allowed him to object, may also prevent the consenting co-occupant from doing more than urging the police to enter.

*139Perhaps the most serious consequence of the majority’s rule is its operation in domestic abuse situations, a context in which the present question often arises. See Rodriguez, 497 U. S., at 179; United States v. Donlin, 982 F. 2d 31 (CA1 1992); Hendrix, supra; People v. Sanders, 904 P. 2d 1311 (Colo. 1995) (en banc); Brandon v. State, 778 P. 2d 221 (Alaska App. 1989). While people living together might typically be accommodating to the wishes of their co-tenants, requests for police assistance may well come from co-inhabitants who are having a disagreement. The Court concludes that because “no sensible person would go inside” in the face of disputed consent, ante, at 113, and the consenting co-tenant thus has “no recognized authority” to insist on the guest’s admission, ante, at 114, a “police officer [has] no better claim to reasonableness in entering than the officer would have in the absence of any consent at all,” ibid. But the police officer’s superior claim to enter is obvious: Mrs. Randolph did not invite the police to join her for dessert and coffee; the officer’s precise purpose in knocking on the door was to assist with a dispute between the Randolphs — one in which Mrs. Randolph felt the need for the protective presence of the police. The majority’s rule apparently forbids police from entering to assist with a domestic dispute if the abuser whose behavior prompted the request for police assistance objects.2

*140The majority acknowledges these concerns, but dismisses them on the ground that its rule can be expected to give rise to exigent situations, and police can then rely on an exigent circumstances exception to justify entry. Ante, at 116-117, n. 6. This is a strange way to justify a rule, and the fact that alternative justifications for entry might arise does not show that entry pursuant to consent is unreasonable. In addition, it is far from clear that an exception for emergency entries suffices to protect the safety of occupants in domestic disputes. See, e. g., United States v. Davis, 290 F. 3d 1239, 1240-1241 (CA10 2002) (finding no exigent circumstances justifying entry when police responded to a report of domestic abuse, officers heard no noise upon arrival, defendant told officers that his wife was out of town, and wife then appeared at the door seemingly unharmed but resisted husband’s efforts to close the door).

Rather than give effect to a consenting spouse’s authority to permit entry into her house to avoid such situations, the majority again alters established Fourth Amendment rules to defend giving veto power to the objecting spouse. In response to the concern that police might be turned away under its rule before entry can be justified based on exigency, the majority creates a new rule: A “good reason” to enter, coupled with one occupant’s consent, will ensure that a police officer is “lawfully in the premises.” Ante, at 118. As support for this “consent plus a good reason” rule, the majority cites a treatise, which itself refers only to emergency entries. Ibid, (citing 4 W. LaFave, Search and Seizure § 8.3(d), p. 161 (4th ed. 2004)). For the sake of defending what it concedes are fine, formalistic lines, the ma*141jority spins out an entirely new framework for analyzing exigent circumstances. Police may now enter with a “good reason” to believe that “violence (or threat of violence) has just occurred or is about to (or soon will) occur.” Ante, at 118. And apparently a key factor allowing entry with a “good reason” short of exigency is the very consent of one co-occupant the majority finds so inadequate in the first place.

The majority’s analysis alters a great deal of established Fourth Amendment law. The majority imports the concept of “social expectations,” previously used only to determine when a search has occurred and whether a particular person has standing to object to a search, into questions of consent. Ante, at 111, 113. To determine whether entry and search are reasonable, the majority considers a police officer’s subjective motive in asking for consent, which we have otherwise refrained from doing in assessing Fourth Amendment questions. Ante, at 118. And the majority creates a new exception to the warrant requirement to justify warrantless entry short of exigency in potential domestic abuse situations. Ibid.

Considering the majority’s rule is solely concerned with protecting a person who happens to be present at the door when a police officer asks his co-occupant for consent to search, but not one who is asleep in the next room or in the backyard gardening, the majority has taken a great deal of pain in altering Fourth Amendment doctrine, for precious little (if any) gain in privacy. Perhaps one day, as the consequences of the majority’s analytic approach become clearer, today’s opinion will be treated the same way the majority treats our opinions in Matlock and Rodriguez — as a “loose end” to be tied up. Ante, at 121.

One of the concurring opinions states that if it had to choose between a rule that a co-tenant’s consent was valid or a rule that it was not, it would choose the former. Ante, at 125 (opinion of Breyer, J.). The concurrence advises, *142however, that “no single set of legal rules can capture the ever-changing complexity of human life,” ibid., and joins what becomes the majority opinion, “[g]iven the case-specific nature of the Court’s holding,” ante, at 127. What the majority establishes, in its own terms, is “the rule that a physically present inhabitant’s express refusal of consent to a police search is dispositive as to him, regardless of the consent of a fellow occupant.” Ante, at 122-123 (emphasis added). The concurrence joins with the apparent “understandin[g]” that the majority’s “rule” is not a rule at all, but simply a “case-specific” holding. Ante, at 127 (opinion of Breyer, J.). The end result is a complete lack of practical guidance for the police in the field, let alone for the lower courts.

* *

Our third-party consent cases have recognized that a person who shares common areas with others “assume[s] the risk that one of their number might permit the common area to be searched.” Matlock, 415 U. S., at 171, n. 7. The majority reminds us, in high tones, that a man’s home is his castle, ante, at 115, but even under the majority’s rule, it is not his castle if he happens to be absent, asleep in the keep, or otherwise engaged when the constable arrives at the gate. Then it is his co-owner’s castle. And, of course, it is not his castle if he wants to consent to entry, but his co-owner objects. Rather than constitutionalize such an arbitrary rule, we should acknowledge that a decision to share a private place, like a decision to share a secret or a confidential document, necessarily entails the risk that those with whom we share may in turn choose to share — for their own protection or for other reasons — with the police.

I respectfully dissent.

Justice Scalia,

dissenting.

I join the dissent of The Chief Justice, but add these few words in response to Justice Stevens’ concurrence.

*143It is not as clear to me as it is to Justice Stevens that, at the time the Fourth Amendment was adopted, a police officer could enter a married woman’s home over her objection, and could not enter with only her consent. Nor is it clear to me that the answers to these questions depended solely on who owned the house. It is entirely clear, however, that if the matter did depend solely on property rights, a latter-day alteration of property rights would also produce a latter-day alteration of the Fourth Amendment outcome— without altering the Fourth Amendment itself.

Justice Stevens’ attempted critique of originalism confuses the original import of the Fourth Amendment with the background sources of law to which the Amendment, on its original meaning, referred. From the date of its ratification until well into the 20th century, violation of the Amendment was tied to common-law trespass. See Kyllo v. United States, 533 U. S. 27, 31-32 (2001); see also California v. Acevedo, 500 U. S. 565, 581, 583 (1991) (SCALIA, J., concurring in judgment). On the basis of that connection, someone who had power to license the search of a house by a private party could authorize a police search. See 1 Restatement of Torts § 167, and Comment b (1934); see also Williams v. Howard, 110 S. C. 82, 96 S. E. 251 (1918); Fennemore v. Armstrong, 29 Del. 35, 96 A. 204 (Super. Ct. 1915). The issue of who could give such consent generally depended, in turn, on “historical and legal refinements” of property law. United States v. Matlock, 415 U. S. 164, 171, n. 7 (1974). As property law developed, individuals who previously could not authorize a search might become able to do so, and those who once could grant such consent might no longer have that power. But changes in the law of property to which the Fourth Amendment referred would not alter the Amendment’s meaning: that anyone capable of authorizing a search by a private party could consent to a warrantless search by the police.

*144There is nothing new or surprising in the proposition that our unchanging Constitution refers to other bodies of law that might themselves change. The Fifth Amendment provides, for instance, that “private property” shall not “be taken for public use, without just compensation”; but it does not purport to define property rights. We have consistently held that “the existence of a property interest is determined by reference to ‘existing rules or understandings that stem from an independent source such as state law.’” Phillips v. Washington Legal Foundation, 524 U. S. 156, 164 (1998) (quoting Board of Regents of State Colleges v. Roth, 408 U. S. 564, 577 (1972)). The same is true of the Fourteenth Amendment Due Process Clause’s protection of “property.” See Castle Rock v. Gonzales, 545 U. S. 748, 756 (2005). This reference to changeable law presents no problem for the originalist. No one supposes that the meaning of the Constitution changes as States expand and contract property rights. If it is indeed true, therefore, that a wife in 1791 could not authorize the search of her husband’s house, the fact that current property law provides otherwise is no more troublesome for the originalist than the well-established fact that a State must compensate its takings of even those property rights that did not exist at the time of the founding.

In any event, Justice Stevens’ panegyric to the equal rights of women under modern property law does not support his conclusion that “[ajssuming . . . both spouses are competent, neither one is a master possessing the power to override the other’s constitutional right to deny entry to their castle.” Ante, at 125. The issue at hand is what to do when there is a conflict between two equals. Now that women have authority to consent, as Justice Stevens claims men alone once did, it does not follow that the spouse who refuses consent should be the winner of the contest. Justice Stevens could just as well have followed the same historical developments to the opposite conclusion: Now that *145“the male and the female are equal partners,” ibid., and women can consent to a search of their property, men can no longer obstruct their wishes. Men and women are no more “equal” in the majority’s regime, where both sexes can veto each other’s consent, than on the dissent’s view, where both sexes cannot.

Finally, I must express grave doubt that today’s decision deserves Justice Stevens’ celebration as part of the forward march of women’s equality. Given the usual patterns of domestic violence, how often can police be expected to encounter the situation in which a man urges them to enter the home while a woman simultaneously demands that they stay out? The most common practical effect of today’s decision, insofar as the contest between the sexes is concerned, is to give men the power to stop women from allowing police into their homes — which is, curiously enough, precisely the power that Justice Stevens disapprovingly presumes men had in 1791.

Justice Thomas,

dissenting.

The Court has long recognized that “[i]t is an act of responsible citizenship for individuals to give whatever information they may have to aid in law enforcement.” Miranda v. Arizona, 384 U. S. 436, 477-478 (1966). Consistent with this principle, the Court held in Coolidge v. New Hampshire, 403 U. S. 443 (1971), that no Fourth Amendment search occurs where, as here, the spouse of an accused voluntarily leads the police to potential evidence of wrongdoing by the accused. Id., at 486-490. Because Coolidge squarely controls this case, the Court need not address whether police could permissibly have conducted a general search of the Randolph home, based on Mrs. Randolph’s consent. I respectfully dissent.

In the instant case, Mrs. Randolph told police responding to a domestic dispute that respondent was using a substan*146tial quantity of cocaine. Upon police request, she consented to a general search of her residence to investigate her statements. However, as the Court’s recitation of the facts demonstrates, ante, at 107, the record is clear that no such general search occurred. Instead, Sergeant Brett Murray asked Mrs. Randolph where the cocaine was located, and she showed him to an upstairs bedroom, where he saw the “piece of cut straw” on a dresser. Corrected Tr. of Motion to Suppression Hearing in Case No. 2001R-699 (Super. Ct. Sumter Cty., Ga., Oct. 3, 2002), pp. 8-9. Upon closer examination, Sergeant Murray observed white residue on the straw, and concluded the straw had been used for ingesting cocaine. Id., at 8. He then collected the straw and the residue as evidence. Id., at 9.

Sergeant Murray’s entry into the Randolphs’ home at the invitation of Mrs. Randolph to be shown evidence of respondent’s cocaine use does not constitute a Fourth Amendment search. Under this Court’s precedents, only the action of an agent of the government can constitute a search within the meaning of the Fourth Amendment, because that Amendment “was intended as a restraint upon the activities of sovereign authority, and was not intended to be a limitation upon other than governmental agencies.” Burdeau v. McDowell, 256 U. S. 465, 475 (1921) (emphasis added). See also Coolidge, 403 U. S., at 487. Applying this principle in Coolidge, the Court held that when a citizen leads police officers into a home shared with her spouse to show them evidence relevant to their investigation into a crime, that citizen is not acting as an agent of the police, and thus no Fourth Amendment search has occurred. Id., at 488-498.

Review of the facts in Coolidge clearly demonstrates that it governs this case. While the police interrogated Coolidge as part of their investigation into a murder, two other officers were sent to his house to speak with his wife. Id., at 485. During the course of questioning Mrs. Coolidge, the *147police asked whether her husband owned any guns. Id., at 486. Mrs. Coolidge replied in the affirmative, and offered to retrieve the weapons for the police, apparently operating under the assumption that doing so would help to exonerate her husband. Ibid. The police accompanied Mrs. Coolidge to the bedroom to collect the guns, as well as clothing that Mrs. Coolidge told them her husband had been wearing the night of the murder. Ibid.

Before this Court, Coolidge argued that the evidence of the guns and clothing should be suppressed as the product of an unlawful search because Mrs. Coolidge was acting as an “‘instrument,’” or agent, of the police by complying with a “ ‘demand’ ” made by them. Id., at 487. The Court recognized that, had Mrs. Coolidge sought out the guns to give to police wholly on her own initiative, “there can be no doubt under existing law that the articles would later have been admissible in evidence.” Ibid. That she did so in cooperation with police pursuant to their request did not transform her into their agent; after all, “it is no part of the policy underlying the Fourth and Fourteenth Amendments to discourage citizens from aiding to the utmost of their ability in the apprehension of criminals.” Id., at 488. Because the police were “acting normally and properly” when they asked about any guns, and questioning Mrs. Coolidge about the clothing was “logical and in no way coercive,” the Fourth Amendment did not require police to “avert their eyes” when Mrs. Coolidge produced the guns and clothes for inspection.1 Id., at 488-489.

*148This case is indistinguishable from Coolidge, compelling the conclusion that Mrs. Randolph was not acting as an agent of the police when she admitted Sergeant Murray into her home and led him to the incriminating evidence.2 Just as Mrs. Coolidge could, of her own accord, have offered her husband’s weapons and clothing to the police without implicating the Fourth Amendment, so too could Mrs. Randolph have simply retrieved the straw from the house and given it to Sergeant Murray. Indeed, the majority appears to concede as much. Ante, at 116 (“The co-tenant acting on his own initiative may be able to deliver evidence to the police, Coolidge, supra, at 487-489 ..., and can tell the police what he knows, for use before a magistrate in getting a warrant”). Drawing a constitutionally significant distinction between what occurred here and Mrs. Randolph’s independent production of the relevant evidence is both inconsistent with Coolidge and unduly formalistic.3

Accordingly, the trial court appropriately denied respondent’s motion to suppress the evidence Mrs. Randolph pro*149vided to the police and the evidence obtained as a result of the consequent search warrant. I would therefore reverse the judgment of the Supreme Court of Georgia.