Mb. Justice Harlan

delivered the opinion of the Court.

William Spinelli was convicted under 18 U. S. C. i 19521 of traveling to St. Louis, Missouri, from a nearby Illinois suburb with the intention of conducting gambling activities proscribed by Missouri law. See Mo. Rev. Stat. § 563.360 (1959). At every appropriate stage in the proceedings in the lower courts, the petitioner challenged the constitutionality of the warrant which authorized the FBI search that uncovered the evidence necessary for his conviction. At each stage, Spinelli’s challenge was treated in a different way. At a pretrial suppression hearing, the United States District Court for the Eastern District of Missouri held that Spinelli *412lacked standing to raise a Fourth Amendment objection. A unanimous panel of the Court of Appeals for the Eighth Circuit rejected the District Court’s ground, a majority holding further that the warrant was issued without probable cause. After an en banc rehearing, the Court of Appeals sustained the warrant and affirmed the conviction by a vote of six to two. 382 F. 2d 871. Both the majority and dissenting en banc opinions reflect a most conscientious effort to apply the principles we announced in Aguilar v. Texas, 378 U. S. 108 (1964), to a factual situation whose basic characteristics have not been at all uncommon in recent search warrant cases. Believing it desirable that the principles of Aguilar should be further explicated, we granted certiorari, 390 U. S. 942, our writ being later limited to the question of the constitutional validity of the search and seizure.2 391 U. S. 933. For reasons that follow we reverse.

In Aguilar, a search warrant had issued upon an affidavit of police officers who swore only that they had “received reliable information from a credible person and do believe” that narcotics were being illegally stored on the described premises. While recognizing that the constitutional requirement of probable cause can be satisfied by hearsay information, this Court held the *413affidavit inadequate for two reasons. First, the application failed to set forth any of the “underlying circumstances” necessary to enable the magistrate independently to judge of the validity of the informant’s conclusion that the narcotics were where he said they were. Second, the affiant-officers did not attempt to support their claim that their informant was “ 'credible’ or his information 'reliable.’ ” The Government is, however, quite right in saying that the FBI affidavit in the present case is more ample than that in Aguilar. Not only does it contain a report from an anonymous informant, but it also contains a report of an independent FBI investigation which is said to corroborate the informant’s tip. We are, then, required to delineate the manner in which Aguilar’s two-pronged test should be applied in these circumstances.

In essence, the affidavit, reproduced in full in the Appendix to this opinion, contained the following allegations:3

1. The FBI had kept track of Spinelli’s movements on five days during the month of August 1965. On four of these occasions, Spinelli was seen crossing one of two bridges leading from Illinois into St. Louis, Missouri, between 11 a. m. and 12:15 p. m. On four of the five days, Spinelli was also seen parking his car in a lot used by residents of an apartment house at 1108 Indian Circle Drive in St. Louis, between 3:30 p. m. and 4:45 p. m.4

*414On one day, Spinelli was followed further and seen to enter a particular apartment in the building.

2. An FBI check with the telephone company revealed that this apartment contained two telephones listed under the name of Grace P. Hagen, and carrying the numbers WYdown 4-0029 and WYdown 4-0136.

3. The application stated that “William Spinelli is known to this affiant and to federal law enforcement agents and local law enforcement agents as a bookmaker, an associate of bookmakers, a gambler, and an associate of gamblers.”

4. Finally, it was stated that the FBI “has been informed by a confidential reliable informant that William Spinelli is operating a handbook and accepting wagers and disseminating wagering information by means of the telephones which have been assigned the numbers WYdown 4-0029 and WYdown 4-0136.”

There can be no question that the last item mentioned, detailing the informant’s tip, has a fundamental place in this warrant application. Without it, probable cause could not be established. The first two items reflect only innocent-seeming activity and data. Spinelli’s travels to and from the apartment building and his entry into a particular apartment on one occasion could hardly be taken as bespeaking gambling activity; and there is surely nothing unusual about an apartment containing two separate telephones. Many a householder indulges himself in this petty luxury. Finally, the allegation that Spinelli was “known” to the affiant and to other federal and local law enforcement officers as a gambler and an associate of gamblers is but a bald and unilluminating assertion of suspicion that is entitled to no weight in appraising the magistrate’s decision. Nathanson v. United States, 290 U. S. 41, 46 (1933).

*415So much indeed the Government does not deny. Rather, following the reasoning of the Court of Appeals, the Government claims that the informant’s tip gives a suspicious color to the FBI’s reports detailing Spinelli’s innocent-seeming conduct and that, conversely, the FBI’s surveillance corroborates the informant’s tip, thereby entitling it to more weight. It is true, of course, that the magistrate is obligated to render a judgment based upon a common-sense reading of the entire affidavit. United States v. Ventresca, 380 U. S. 102, 108 (1965). We believe, however, that the “totality of circumstances” approach taken by the Court of Appeals paints with too broad a brush. Where, as here, the informer’s tip is a necessary element in a finding of probable cause, its proper weight must be determined by a more precise analysis.

The informer’s report must first be measured against Aguilar’s standards so that its probative value can be assessed. If the tip is found inadequate under Aguilar, the other allegations which corroborate the information contained in the hearsay report should then be considered. At this stage as well, however, the standards enunciated in Aguilar must inform the magistrate’s decision. He must ask: Can it fairly be said that the tip, even when certain parts of it have been corroborated by independent sources, is as trustworthy as a tip which would pass Aguilar’s tests without independent corroboration? Aguilar is relevant at this stage of the inquiry as well because the tests it establishes were designed to implement the long-standing principle that probable cause must be determined by a “neutral and detached magistrate,” and not by “the officer engaged in the often competitive enterprise of ferreting out crime.” Johnson v. United States, 333 U. S. 10, 14 (1948). A magistrate cannot be said to have properly discharged his constitutional duty if he relies on an informer’s tip which — even *416when partially corroborated — is not as reliable as one which passes Aguilar’s requirements when standing alone.

Applying these principles to the present case, we first consider the weight to be given the informer’s tip when it is considered apart from the rest of the affidavit. It is clear that a Commissioner could not credit it without abdicating his constitutional function. Though the affi-ant swore that his confidant was “reliable,” he offered the magistrate no reason in support of this conclusion. Perhaps even more important is the fact that Aguilar’s other test has not been satisfied. The tip does not contain a sufficient statement of the underlying circumstances from which the informer concluded that Spinelli was running a bookmaking operation. We are not told how the FBI’s source received his information — it is not alleged that the informant personally observed Spinelli at work or that he had ever placed a bet with him. Moreover, if the informant came by the information indirectly, he did not explain why his sources were reliable. Cf. Jaben v. United States, 381 U. S. 214 (1965). In the absence of a statement detailing the manner in which the information was gathered, it is especially important that the tip describe the accused’s criminal activity in sufficient detail that the magistrate may know 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.

The detail provided by the informant in Draper v. United States, 358 U. S. 307 (1959), provides a suitable benchmark. While Hereford, the Government’s informer in that case, did not state the way in which he had obtained his information, he reported that Draper had gone to Chicago the day before by train and that he would return to Denver by train with three ounces of heroin on one of two specified mornings. Moreover, *417Hereford went on to describe, with minute particularity, the clothes that Draper would be wearing upon his arrival at the Denver station. A magistrate, when confronted with such detail, could reasonably infer that the informant had gained his information in a reliable way.5 Such an inference cannot be made in the present case. Here, the only facts supplied were that Spinelli was using two specified telephones and that these phones were being used in gambling operations. This meager report could easily have been obtained from an offhand remark heard at a neighborhood bar.

Nor do we believe that the patent doubts Aguilar raises as to the report’s reliability are adequately resolved by a consideration of the allegations detailing the FBI’s independent investigative efforts. At most, these allegations indicated that Spinelli could have used the telephones specified by the informant for some purpose. This cannot by itself be said to support both the inference that the informer was generally trustworthy and that he had made his charge against Spinelli on the basis of information obtained in a reliable way. Once again, Draper provides a relevant comparison. Independent police work in that case corroborated much more than one small detail that had been provided by the informant. There, the police, upon meeting the inbound Denver train on the second morning specified by informer Hereford, saw a man whose dress corresponded precisely to Hereford’s detailed description. It was then apparent that the informant had not been fabricating his report out of whole cloth; since the report was of the sort which in common experience may be recognized as having been *418obtained in a reliable way, it was perfectly clear that probable cause had been established.

We conclude, then, that in the present case the informant’s tip — even when corroborated to the extent indicated — was not sufficient to provide the basis for a finding of probable cause. This is not to say that the tip was so insubstantial that it could not properly have counted in the magistrate’s determination. Rather, it needed some further support. When we look to the other parts of the application, however, we find nothing alleged which would permit the suspicions engendered by the informant’s report to ripen into a judgment that a crime was probably being committed. As we have already seen, the allegations detailing the FBI’s surveillance of Spinelli and its investigation of the telephone company records contain no suggestion of criminal conduct when taken by themselves — and they are not endowed with an aura of suspicion by virtue of the informer’s tip. Nor do we find that the FBI’s reports take on a sinister color when read in light of common knowledge that bookmaking is often carried on over the telephone and from premises ostensibly used by others for perfectly normal purposes. Such an argument would carry weight in a situation in which the premises contain an unusual number of telephones or abnormal activity is observed, cf. McCray v. Illinois, 386 U. S. 300, 302 (1967), but it does not fit this case where neither of these factors is present.6 All that remains to be considered is the flat statement that Spinelli was “known” to the FBI and others as a gambler. But just as a simple assertion of police suspicion is not itself a sufficient basis for a magistrate’s finding of probable cause, we do not believe it may be used to give *419additional weight to allegations that would otherwise be insufficient.

The affidavit, then, falls short of the standards set forth in Aguilar, Draper, and our other decisions that give content to the notion of probable cause.7 In holding as we have done, we do not retreat from the established propositions that only the probability, and not a prima facie showing, of criminal activity is the standard of probable cause, Beck v. Ohio, 379 U. S. 89, 96 (1964); that affidavits of probable cause are tested by much less rigorous standards than those governing the admissibility of evidence at trial, McCray v. Illinois, 386 U. S. 300, 311 (1967); that in judging probable cause issuing magistrates are not to be confined by niggardly limitations or by restrictions on the use of their common sense, United States v. Ventresca, 380 U. S. 102, 108 (1965); and that their determination of probable cause should be paid great deference by reviewing courts, Jones v. United States, 362 U. S. 257, 270-271 (1960). But we cannot sustain this warrant without diluting important safeguards that assure that the judgment of a disinterested judicial officer will interpose itself between the police and the citizenry.8

*420The judgment of the Court of Appeals is reversed and the case is remanded to that court for further proceedings consistent with this opinion.

It is so ordered.

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

APPENDIX TO OPINION OF THE COURT.

Affidavit in Support of Search Warrant.

I, Robert L. Bender, being duly sworn, depose and say that I am a Special Agent of the Federal Bureau of Investigation, and as such am authorized to make searches and seizures.

That on August 6, 1965, at approximately 11:44 a. m., William Spinelli was observed by an Agent of the Federal Bureau of Investigation driving a 1964 Ford convertible, Missouri license HC3-649, onto the Eastern approach of the Veterans Bridge leading from East St. Louis, Illinois, to St. Louis, Missouri.

That on August 11, 1965, at approximately 11:16 a. m., William Spinelli was observed by an Agent of the Federal Bureau of Investigation driving a 1964 Ford convertible, Missouri license HC3-649, onto the Eastern approach of the Eads Bridge leading from East St. Louis, Illinois, to St. Louis, Missouri.

Further, at approximately 11:18 a. m. on August 11, 1965, I observed William Spinelli driving the aforesaid Ford convertible from the Western approach of the Eads Bridge into St. Louis, Missouri.

Further, at approximately 4:40 p. m. on August 11, 1965, I observed the aforesaid Ford convertible, bearing Missouri license HC3-649, parked in a parking lot used by residents of The Chieftain Manor Apartments, approximately one block east of 1108 Indian Circle Drive.

On August 12, 1965, at approximately 12:07 p. m., *421William. Spinelli was observed by an Agent of the Federal Bureau of Investigation driving the aforesaid 1964 Ford convertible onto the Eastern approach of the Veterans Bridge from East St. Louis, Illinois, in the direction of St. Louis, Missouri.

Further, on August 12, 1965, at approximately 3:46 p. m., I observed William Spinelli driving the aforesaid 1964 Ford convertible onto the parking lot used by the residents of The Chieftain Manor Apartments approximately one block east of 1108 Indian Circle Drive.

Further, on August 12, 1965, at approximately 3:49 p. m., William Spinelli was observed by an Agent of the Federal Bureau of Investigation entering the front entrance of the two-story apartment building located at 1108 Indian Circle Drive, this building being one of The Chieftain Manor Apartments.

On August 13, 1965, at approximately 11:08 a. m., William Spinelli was observed by an Agent of the Federal Bureau of Investigation driving the aforesaid Ford convertible onto the Eastern approach of the Eads Bridge from East St. Louis, Illinois, heading towards St. Louis, Missouri.

Further, on August 13, 1965, at approximately 11:11 a. m., I observed William Spinelli driving the aforesaid Ford convertible from the Western approach of the Eads Bridge into St. Louis, Missouri.

Further, on August 13, 1965, at approximately 3:45 p. m., I observed William Spijielli driving the aforesaid 1964 Ford convertible onto the parking area used by residents of The Chieftain Manor Apartments, said parking area being approximately one block from 1108 Indian Circle Drive.

Further, on August 13, 1965, at approximately 3:55 p. m., William Spinelli was observed by an Agent of the Federal Bureau of Investigation entering the corner apartment located on the second floor in the southwest corner, known as Apartment F, of the two-story *422apartment building known and numbered as 1108 Indian Circle Drive.

On August 16, 1965, at approximately 3:22 p. m., I observed William Spinelli driving the aforesaid Ford convertible onto the parking lot used by the residents of The Chieftain Manor Apartments approximately one block east of 1108 Indian Circle Drive.

Further, an Agent of the F. B. I. observed William Spinelli alight from the aforesaid Ford convertible and walk toward the apartment building located at 1108 Indian Circle Drive.

The records of the Southwestern Bell Telephone Company reflect that there are two telephones located in the southwest corner apartment on the second floor of the apartment building located at 1108 Indian Circle Drive under the name of Grace P. Hagen. The numbers listed in the Southwestern Bell Telephone Company records for the aforesaid telephones are WYdown 4-0029 and WYdown 4-0136.

William Spinelli is known to this affiant and to federal law enforcement agents and local law enforcement agents as a bookmaker, an associate of bookmakers, a gambler, and an associate of gamblers.

The Federal Bureau of Investigation has been informed by a confidential reliable informant that William Spinelli is operating a handbook and accepting wagers and disseminating wagering information by means of the telephones which have been assigned the numbers WYdown 4-0029 and WYdown 4-0136.

/s/Robert L. Bender,

Robert L. Bender,

Special Agent, Federal Bureau of Investigation.

Subscribed and sworn to before me this 18th day of August, 1965, at St. Louis, Missouri.

/s/ William R. O’Toole.

*423Mr. Justice White,

concurring.

An investigator’s affidavit that he has seen gambling equipment being moved into a house at a specified address will support the issuance of a search warrant. The oath affirms the honesty of the statement and negatives the lie or imagination. Personal observation attests to the facts asserted — that there is gambling equipment on the premises at the named address.

But if the officer simply avers, without more, that there is gambling paraphernalia on certain premises, the warrant should not issue, even though the belief of the officer is an honest one, as evidenced by his oath, and even though the magistrate knows him to be an experienced, intelligent officer who has been reliable in the past. This much was settled in Nathanson v. United States, 290 U. S. 41 (1933), where the Court held insufficient an officer’s affidavit swearing he had cause to believe that there was illegal liquor on the premises for which the warrant was sought. The unsupported assertion or belief of the officer does not satisfy the requirement of probable cause. Jones v. United States, 362 U. S. 257, 269 (1960); Grau v. United States, 287 U. S. 124 (1932); Byars v. United States, 273 U. S. 28, 29 (1927).

What is missing in Nathanson and like cases is a statement of the basis for the affiant’s believing the facts contained in the affidavit — the good “cause” which the officer in Nathanson said he had. If an officer swears that there is gambling equipment at a certain address, the possibilities are (1) that he has seen the equipment; (2) that he has observed or perceived facts from which the presence of the equipment may reasonably be inferred; and (3) that he has obtained the information from someone else. If (1) is true, the affidavit is good. But in (2), the affidavit is insufficient unless the perceived facts are given, for it is the magistrate, not the *424officer, who is to judge the existence of probable cause. Aguilar v. Texas, 378 U. S. 108 (1964); Giordenello v. United States, 357 U. S. 480, 486 (1958); Johnson v. United States, 333 U. S. 10, 14 (1948). With respect to (3), where the officer’s information is hearsay, no warrant should issue absent good cause for crediting that hearsay. Because an affidavit asserting, without more, the location of gambling equipment at a particular address does not claim personal observation of any of the facts by the officer, and because of the likelihood that the information came from an unidentified third party, affidavits of this type are unacceptable.

Neither should the warrant issue if the officer states that there is gambling equipment in a particular apartment and that his information comes from an informant, named or unnamed, since the honesty of the informant and the basis for his report are unknown. Nor would the missing elements be completely supplied by the officer’s oath that the informant has often furnished reliable information in the past. This attests to the honesty of the informant, but Aguilar v. Texas, supra, requires something more — did the information come from observation, or did the informant in turn receive it from another? Absent additional facts for believing the informant’s report, his assertion stands no better than the oath of the officer to the same effect. Indeed, if the affidavit of an officer, known by the magistrate to be honest and experienced, stating that gambling equipment is located in a certain building is unacceptable, it would be quixotic if a similar statement from an honest informant were found to furnish probable cause. A strong argument can be made that both should be acceptable under the Fourth Amendment, but under our cases neither is. The past reliability of the informant can no more furnish probable cause for believing his *425current report than can previous experience with the officer himself.

If the affidavit rests on hearsay — an informant’s report — what is necessary under Aguilar is one of two things: the informant must declare either (1) that he has himself seen or perceived the fact or facts asserted; or (2) that his information is hearsay, but there is good reason for believing it — perhaps one of the usual grounds for crediting hearsay information. The first presents few problems: since the report, although hearsay, purports to be first-hand observation, remaining doubt centers on the honesty of the informant, and that worry is dissipated by the officer’s previous experience with the informant. The other basis for accepting the informant’s report is more complicated. But if, for example, the informer’s hearsay comes from one of the actors in the crime in the nature of admission against interest, the affidavit giving this information should be held sufficient.

I am inclined to agree with the majority that there are limited special circumstances in which an “honest” informant’s report, if sufficiently detailed, will in effect verify itself — that is, the magistrate when confronted with such detail could reasonably infer that the informant had gained his information in a reliable way. See ante, at 417. Detailed information may sometimes imply that the informant himself has observed the facts. Suppose an informant with whom an officer has had satisfactory experience states that there is gambling equipment in the living room of a specified apartment and describes in detail not only the equipment itself but also the appointments and furnishings in the apartment. Detail like this, if true at all, must rest on personal observation either of the informant or of someone else. If the latter, we know nothing of the third person’s honesty or *426sources; he may be making a wholly false report. But it is arguable that on these facts it was the informant himself who has perceived the facts, for the information reported is not usually the subject of casual, day-today conversation. Because the informant is honest and it is probable that he has viewed the facts, there is probable cause for the issuance of a warrant.

So too in the special circumstances of Draper v. United States, 358 U. S. 307 (1959), the kind of information related by the informant is not generally sent ahead of a person’s arrival in a city except to those who are intimately connected with making careful arrangements for meeting him. The informant, posited as honest, somehow had the reported facts, very likely from one of the actors in the plan, or as one of them himself. The majority’s suggestion is that a warrant could have been obtained based only on the informer’s report. I am inclined to agree, although it seems quite plain that if it may be so easily inferred from the affidavit that the informant has himself observed the facts or has them from an actor in the event, no possible harm could come from requiring a statement to that effect, thereby removing the difficult and recurring questions which arise in such situations.

Of course, Draper itself did not proceed on this basis. Instead, the Court pointed out that when the officer saw a person getting off the train at the specified time, dressed and conducting himself precisely as the informant had predicted, all but the critical fact with respect to possessing narcotics had then been verified and for that reason the officer had “reasonable grounds” to believe also that Draper was carrying narcotics. Unquestionably, verification of arrival time, dress, and gait reinforced the honesty of the informant — he had not reported a made-up story. But if what Draper stands for is that the existence of the tenth and critical fact *427is made sufficiently probable to justify the issuance of a warrant by verifying nine other facts coming from the same source, I have my doubts about that case.

In the first place, the proposition is not that the tenth fact may be logically inferred from the other nine or that the tenth fact is usually found in conjunction with the other nine. No one would suggest that just anyone getting off the 10:30 train dressed as Draper was, with a brisk walk and carrying a zipper bag, should be arrested for carrying narcotics. The thrust of Draper is not that the verified facts have independent significance with respect to proof of the tenth. The 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.

But the Court’s cases have already rejected for Fourth Amendment purposes the notion that the past reliability of an officer is sufficient reason for believing his current assertions. 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.

The tension between Draper and the Nathanson-Aguilar line of cases is evident from the course followed *428by the majority opinion. First, it is held that the report from a reliable informant that Spinelli is using two telephones with specified numbers to conduct a gambling business plus Spinelli’s reputation in police circles as a gambler does not add up to probable cause. This is wholly consistent with Aguilar and Nathanson: the informant did not reveal whether he had personally observed the facts or heard them from another and, if the latter, no basis for crediting the hearsay was presented. Nor were the facts, as Mr. Justice Harlan says, of such a nature that they normally would be obtainable only by the personal observation of the informant himself. The police, however, did not stop with the informant’s report. Independently, they established the existence of two phones having the given numbers and located them in an apartment house which Spinelli was regularly frequenting away from his home. There remained little question but that Spinelli was using the phones, and it was a fair inference that the use was not for domestic but for business purposes. The informant had claimed the business involved gambling. Since his specific information about Spinelli using two phones with particular numbers had been verified, did not his allegation about gambling thereby become sufficiently more believable if the Draper principle is to be given any scope at all? I would think so, particularly since the information from the informant which was verified was not neutral, irrelevant information but was material to proving the gambling allegation: two phones with different numbers in an apartment used away from home indicates a business use in an operation, like bookmaking, where multiple phones are needed. The Draper approach would reasonably justify the issuance of a warrant in this case, particularly since the police had some awareness of Spinelli’s past activities. The majority, how*429ever, while seemingly embracing Draper, confines that case to its own facts. Pending full-scale reconsideration of that case, on the one hand, or of the Nathanson-Aguilar cases on the other, I join the opinion of the Court and the judgment of reversal, especially since a vote to affirm would produce an equally divided Court.

Me. Justice Black,

dissenting.

In my view, this Court’s decision in Aguilar v. Texas, 378 U. S. 108 (1964), was bad enough. That decision went very far toward elevating the magistrate’s hearing for issuance of a search warrant to a full-fledged trial, where witnesses must be brought forward to attest personally to all the facts alleged. But not content with this, the Court today expands Aguilar to almost unbelievable proportions. Of course, it would strengthen the probable-cause presentation if eyewitnesses could testify that they saw the defendant commit the crime. It would be stronger still if these witnesses could explain in detail the nature of the sensual perceptions on which they based their “conclusion” that the person they had seen was the defendant and that he was responsible for the events they observed. Nothing in our Constitution, however, requires that the facts be established with that degree of certainty and with such elaborate specificity before a policeman can be authorized by a disinterested magistrate to conduct a carefully limited search.

The Fourth Amendment provides that “no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.” In this case a search warrant was issued supported by an oath and particularly describing the place to be searched and the things to be seized. The supporting oath was *430three printed pages and the full text of it is included in an Appendix to the Court’s opinion. The magistrate, I think properly, held the information set forth sufficient facts to show “probable cause” that the defendant was violating the law. Six members of the Court of Appeals also agreed that the affidavit was sufficient to show probable cause. A majority of this Court today holds, however, that the magistrate and all of these judges were wrong. In doing so, they substitute their own opinion for that of the local magistrate and the circuit judges, and reject the en banc factual conclusion of the Eighth Circuit and reverse the judgment based upon that factual conclusion. I cannot join in any such disposition of an issue so vital to the administration of justice, and dissent as vigorously as I can.

I repeat my belief that the affidavit given the magistrate was more than ample to show probable cause of the petitioner’s guilt. The affidavit meticulously set out facts sufficient to show the following:

1. The petitioner had been shown going to and coming from a room in an apartment which contained two telephones listed under the name of another person. Nothing in the record indicates that the apartment was of that large and luxurious type which could only be occupied by a person to whom it would be a “petty luxury” to have two separate telephones, with different numbers, both listed under the name of a person who did not live there.

2. The petitioner’s car had been observed parked in the apartment’s parking lot. This fact was, of course, highly relevant in showing that the petitioner was extremely interested in some enterprise which was located in the apartment.

3. The FBI had been informed by a reliable informant that the petitioner was accepting wagering information by telephones — the particular telephones located in the *431apartment the defendant had been repeatedly visiting. Unless the Court, going beyond the requirements of the Fourth Amendment, wishes to require magistrates to hold trials before issuing warrants, it is not necessary— as the Court holds — to have the affiant explain “the underlying circumstances from which the informer concluded that Spinelli was running a bookmaking operation.” Ante, at 416.

4. The petitioner was known by federal and local law enforcement agents as a bookmaker and an associate of gamblers. I cannot agree with the Court that this knowledge was only a “bald and unilluminating assertion of suspicion that is entitled to no weight in appraising the magistrate’s decision.” Ante, at 414. Although the statement is hearsay that might not be admissible in a regular trial, everyone knows, unless he shuts his eyes to the realities of life, that this is a relevant fact which, together with other circumstances, might indicate a factual probability that gambling is taking place.

The foregoing facts should be enough to constitute probable cause for anyone who does not believe that the only way to obtain a search warrant is to prove beyond a reasonable doubt that a defendant is guilty. Even Aguilar, on which the Court relies, cannot support the contrary result, at least as that decision was written before today’s massive escalation of it. In Aguilar the Court dealt with an affidavit that stated only:

“Affiants have received reliable information from a credible person and do believe that heroin . . . and other narcotics and narcotic paraphernalia are being kept at the above described premises for the purpose of sale and use contrary to the provisions of the law.” 378 U. S., at 109.

The Court held, over the dissent of Mr. Justice Clark, Mr. Justice Stewart, and myself, that this unsupported conclusion of an unidentified informant provided no basis *432for the magistrate to make an independent judgment as to the persuasiveness of the facts relied upon to show probable cause. Here, of course, we have much more, and the Court in Aguilar was careful to point out that additional information of the kind presented in the affidavit before us now would be highly relevant:

“If the fact and results of such a surveillance had been appropriately presented to the magistrate, this would, of course, present an entirely different case.” 378 U. S., at 109, n. 1.

In the present case even the two-judge minority of the court below recognized, as this Court seems to recognize today, that this additional information took the case beyond the rule of Aguilar. Six of the other circuit judges disagreed with the two dissenting judges, finding that all the circumstances considered together could support a reasonable judgment that gambling probably was taking place. I fully agree with this carefully considered opinion of the court below.

I regret to say I consider today’s decision an indefensible departure from the principles of our former cases. Less than four years ago we reaffirmed these principles in United States v. Ventresca, 380 U. S. 102, 108 (1965):

“If the teachings of the Court’s cases are to be followed and the constitutional policy served, affidavits for search warrants . . . must be tested and interpreted by magistrates and courts in a commonsense and realistic fashion. . . . Technical requirements of elaborate specificity once exacted under common law pleadings have no proper place in this area.”

See also Husty v. United States, 282 U. S. 694, 700-701 (1931).

Departures of this kind are responsible for considerable uneasiness in our lower courts, and I must say I *433am deeply troubled by the statements of Judge Gibson in the court below:

“I am, indeed, disturbed by decision after decision of our courts which place increasingly technical burdens upon law enforcement officials. I am disturbed by these decisions that appear to relentlessly chip away at the ever narrowing area of effective police operation. I believe the holdings in Aguilar, and Rugendorf v. United States, 376 U. S. 528 (1964) are sufficient to protect the privacy of individuals from hastily conceived intrusions, and I do not think the limitations and requirements on the issuance of search warrants should be expanded by setting up over-technical requirements approaching the now discarded pitfalls of common law pleadings. Moreover, if we become increasingly technical and rigid in our demands upon police officers, I fear we make it increasingly easy for criminals to operate, detected but unpunished. I feel the significant movement of the law beyond its present state is unwarranted, unneeded, and dangerous to law enforcement efficiency.” (Dissenting from panel opinion.)

The Court of Appeals in this case took a sensible view of the Fourth Amendment, and I would wholeheartedly affirm its decision.

Mapp v. Ohio, 367 U. S. 643, decided in 1961, held for the first time that the Fourth Amendment and the exclusionary rule of Weeks v. United States, 232 U. S. 383 (1914) are now applicable to the States. That Amendment provides that search warrants shall not be issued without probable cause. The existence of probable cause is a factual matter that calls for the determination of a factual question. While no statistics are immediately available, questions of probable cause to issue search *434warrants and to make arrests are doubtless involved in many thousands of cases in state courts. All of those probable-cause state cases are now potentially reviewable by this Court. It is, of course, physically impossible for this Court to review the evidence in all or even a substantial percentage of those cases. Consequently, whether desirable or not, we must inevitably accept most of the fact findings of the state courts, particularly when, as here in a federal case, both the trial and appellate courts have decided the facts the same way. It cannot be said that the trial judge and six members of the Court of Appeals committed flagrant error in finding from evidence that the magistrate had probable cause to issue the search warrant here. It seems to me that this Court would best serve itself and the administration of justice by accepting the judgment of the two courts below. After all, they too are lawyers and judges, and much closer to the practical, everyday affairs of life than we are.

Notwithstanding the Court’s belief to the contrary, I think that in holding as it does, the Court does:

“retreat from the established propositions that only the probability, and not a prima facie showing, of criminal activity is the standard of probable cause, Beck v. Ohio, 379 U. S. 89, 96 (1964); that affidavits of probable cause are tested by much less rigorous standards than those governing the admissibility of evidence at trial, McCray v. Illinois, 386 U. S. 300, 311 (1967); that in judging probable cause issuing magistrates are not to be confined by niggardly limitations or by restrictions on the use of their common sense, United States v. Ventresca, 380 U. S. 102, 108 (1965); and that their determination of probable cause should be paid great deference by reviewing courts, Jones v. United States, 362 U. S. 257, 270-271 (I960).” Ante, at 419.

*435In fact, I believe the Court is moving rapidly, through complex analyses and obfuscatory language, toward the holding that no magistrate can issue a warrant unless according to some unknown standard of proof he can be persuaded that the suspect defendant is actually guilty of a crime. I would affirm this conviction.

Mr. Justice Fortas,

dissenting.

My Brother Harlan’s opinion for the Court is animated by a conviction which I share that “[t]he security of one’s privacy against arbitrary intrusion by the police — which is at the core of the Fourth Amendment— is basic to a free society.” Wolf v. Colorado, 338 U. S. 25, 27 (1949).

We may well insist upon a sympathetic and even an indulgent view of the latitude which must be accorded to the police for performance of their vital task; but only a foolish or careless people will deduce from this that the public welfare requires or permits the police to disregard the restraints on their actions which historic struggles for freedom have developed for the protection of liberty and dignity of citizens against arbitrary state power.

As Justice Jackson (dissenting) stated in Brinegar v. United States, 338 U. S. 160, 180-181 (1949):

“[The provisions of the Fourth Amendment] 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. Uncontrolled search and seizure is one of the first and most effective weapons in the arsenal of every arbitrary government. And one need only briefly to have dwelt and worked among a people possessed of many admirable qualities but deprived of these rights to know that the *436human personality deteriorates and dignity and self-reliance disappear where homes, persons and possessions are subject at any hour to unheralded search and seizure by the police.”

History1 teaches us that this protection requires that the judgment of a judicial officer be interposed between the police, hot in pursuit of their appointed target, and the citizen;2 that the judicial officer must judge and not merely rubber-stamp; and that his judgment must be based upon judicially reliable facts adequate to demonstrate that the search is justified by the probability that it will yield the fruits or instruments of crime — or, as this Court has only recently ruled, tangible evidence of its commission.3 The exceptions to the requirement of a search warrant have always been narrowly restricted4 because of this Court’s long-standing awareness of the fundamental role of the magistrate’s judgment in the preservation of a proper balance between individual freedom and state power. See Trupiano v. United States, 334 U. S. 699, 700 (1948).

Today’s decision deals, not with the necessity of obtaining a warrant prior to search, but with the difficult problem of the nature of the showing that must be made *437before the magistrate to justify his issuance of a search warrant. While I do not subscribe to the criticism of the majority expressed by my Brother Black in dissent, I believe — with all respect — that the majority is in error in holding that the affidavit supporting the warrant in this case is constitutionally inadequate.

The affidavit is unusually long and detailed. In fact, it recites so many minute and detailed facts developed in the course of the investigation of Spinelli that its substance is somewhat obscured. It is paradoxical that this very fullness of the affidavit may be the source of the constitutional infirmity that the majority finds. Stated in language more direct and less circumstantial than that used by the FBI agent who executed the affidavit, it sets forth that the FBI has been informed that Spinelli is accepting wagers by means of telephones numbered WY 4^0029 and WY 4-0136; that Spinelli is known to the affiant agent and to law enforcement agencies as a bookmaker; that telephones numbered WY 4-0029 and WY 4-0136 are located in a certain apartment; that Spinelli was placed under surveillance and his observed movements were such as to show his use of that apartment and to indicate that he frequented the apartment on a regular basis.

Aguilar v. Texas, 378 U. S. 108 (1964), holds that the reference in an affidavit to information described only as received from “a confidential reliable informant,” standing alone, is not an adequate basis for issuance of a search warrant. The majority agrees that the “FBI affidavit in the present case is more ample than that in Aguilar,” but concludes that it is nevertheless constitutionally inadequate. The majority states that the present affidavit fails to meet the “two-pronged test” of Aguilar because (a) it does not set forth the basis for the assertion that the informer is “reliable” and (b) it fails to state the “underlying circumstances” upon which the *438informant based his conclusion that Spinelli was engaged in bookmaking.

The majority acknowledges, however, that its reference to a “two-pronged test” should not be understood as meaning that an affidavit deficient in these respects is necessarily inadequate to support a search warrant. Other facts and circumstances may be attested which will supply the evidence of probable cause needed to support the search warrant. On this general statement we are agreed. Our difference is that I believe such facts and circumstances are present in this case, and the majority arrives at the opposite conclusion.

Aguilar expressly recognized that if, in that case, the affidavit’s conclusory report of the informant’s story had been supplemented by “the fact and results of ... a surveillance . . . this would, of course, present an entirely different case.” 378 U. S., at 109, n. 1. In the present case, as I view it, the affidavit showed not only relevant surveillance, entitled to some probative weight for purposes of the issuance of a search warrant, but also additional, specific facts of significance and adequate reliability: that Spinelli was using two telephone numbers, identified by an “informant” as being used for bookmaking, in his illegal operations; that these telephones were in an identified apartment; and that Spinelli, a known bookmaker,5 frequented the apartment. Certainly, this is enough.

A policeman’s affidavit should not be judged as an entry in an essay contest. It is not “abracadabra.” 6 *439As the majority recognizes, a policeman’s affidavit is entitled to common-sense evaluation. So viewed, I conclude that the judgment of the Court of Appeals for the Eighth Circuit should be affirmed.

Mb. Justice Stewakt,

dissenting.

For substantially the reasons stated by my Brothers Black and Fobtas, I believe the warrant in this case was supported by a sufficient showing of probable cause. I would therefore affirm the judgment.

Justice Stevens

delivered the opinion of the Court.

Baltimore police officers obtained and executed a warrant to search the person of Lawrence McWebb and “the premises known as 2036 Park Avenue third floor apartment.”1 When the police applied for the warrant and when they conducted the search pursuant to the warrant, they reasonably believed that there was only one apartment on the premises described in the warrant. In fact, the third floor was divided into two apartments, one occupied by McWebb and one by respondent Garrison. Before the officers executing the warrant became aware that they were in a separate apartment occupied by respondent, they had discovered the contraband that provided the basis for respondent’s conviction for violating Maryland’s Controlled Substances Act. The question presented is whether the seizure of that contraband was prohibited by the Fourth Amendment.

The trial court denied respondent’s motion to suppress the evidence seized from his apartment, App. 46, and the Mary*81land Court of Special Appeals affirmed. 58 Md. App. 417, 473 A. 2d 514 (1984). The Court of Appeals of Maryland reversed and remanded with instructions to remand the case for a new trial. 303 Md. 385, 494 A. 2d 193 (1985).

There is no question that the warrant was valid and was supported by probable cause. Id., at 392, 494 A. 2d, at 196. The trial court found, and the two appellate courts did not dispute, that after making a reasonable investigation, including a verification of information obtained from a reliable informant, an exterior examination of the three-story building at 2036 Park Avenue, and an inquiry of the utility company, the officer who obtained the warrant reasonably concluded that there was only one apartment on the third floor and that it was occupied by McWebb. App. 41; 58 Md. App., at 433, 473 A. 2d, at 522; 303 Md., at 387-390, 494 A. 2d, at 194-195. When six Baltimore police officers executed the warrant, they fortuitously encountered McWebb in front of the building and used his key to gain admittance to the first-floor hallway and to the locked door at the top of the stairs to the third floor. As they entered the vestibule on the third floor, they encountered respondent, who was standing in the hallway area. The police could see into the interior of both Mc-Webb’s apartment to the left and respondent’s to the right, for the doors to both were open. Only after respondent’s apartment had been entered and heroin, cash, and drug paraphernalia had been found did any of the officers realize that the third floor contained two apartments. App. 41-46. As soon as they became aware of that fact, the search was discontinued. Id., at 32, 39. All of the officers reasonably believed that they were searching McWebb’s apartment.2 No further search of respondent’s apartment was made.

*82The matter on which there is a difference of opinion concerns the proper interpretation of the warrant. A literal reading of its plain language, as well as the language used in the application for the warrant, indicates that it was intended to authorize a search of the entire third floor.3 This is the construction adopted by the intermediate appellate court, see 58 Md. App., at 419, 473 A. 2d, at 515, and it also appears to be the construction adopted by the trial judge. See App. 41. One sentence in the trial judge’s oral opinion, however, lends support to the construction adopted by the Court of Appeals, namely, that the warrant authorized a search of McWebb’s apartment only.4 Under that interpretation, the Court of *83Appeals concluded that the warrant did not authorize the search of respondent’s apartment and the police had no justification for making a warrantless entry into his premises.5

The opinion of the Maryland Court of Appeals relies on Article 26 of the Maryland Declaration of Rights6 and Maryland cases as well as the Fourth Amendment to the Federal Constitution and federal cases. Rather than containing any “plain statement” that the decision rests upon adequate and independent state grounds, see Michigan v. Long, 463 U. S. 1032, 1042 (1983), the opinion indicates that the Maryland constitutional provision is construed in pari materia with the

*84Fourth Amendment.7 We therefore have jurisdiction. Because the result that the Court of Appeals reached did not appear to be required by the Fourth Amendment, we granted certiorari. 475 U. S. 1009 (1986). We reverse.

In our view, the case presents two separate constitutional issues, one concerning the validity of the warrant and the other concerning the reasonableness of the manner in which it was executed. See Dalia v. United States, 441 U. S. 238, 258 (1979). We shall discuss the questions separately.

I-H

The Warrant Clause of the Fourth Amendment categorically prohibits the issuance of any warrant except one “particularly describing the place to be searched and the persons or things to be seized.” The manifest purpose of this particularity requirement was to prevent general searches. By limiting the authorization to search to the specific areas and things for which there is probable cause to search, the requirement ensures that the search will be carefully tailored to its justifications, and will not take on the character of the wide-ranging exploratory searches the Framers intended to prohibit.8 Thus, the scope of a lawful search is “defined by the object of the search and the places in which there is probable cause to believe that it may be found. Just as probable cause to believe that a stolen lawnmower may be found in a garage will not support a warrant to search an upstairs bedroom, probable cause to believe that undocumented aliens are being transported in a van will not justify a warrantless *85search of a suitcase.” United States v. Ross, 456 U. S. 798, 824 (1982).

In this case there is no claim that the “persons or things to be seized” were inadequately described or that there was no probable cause to believe that those things might be found in “the place to be searched” as it was described in the warrant. With the benefit of hindsight, however, we now know that the description of that place was broader than appropriate because it was based on the mistaken belief that there was only one apartment on the third floor of the building at 2036 Park Avenue. The question is whether that factual mistake invalidated a warrant that undoubtedly would have been valid if it had reflected a completely accurate understanding of the building’s floor plan.

Plainly, if the officers had known, or even if they should have known, that there were two separate dwelling units on the third floor of 2036 Park Avenue, they would have been obligated to exclude respondent’s apartment from the scope of the requested warrant. But we must judge the constitutionality of their conduct in light of the information available to them at the time they acted. Those items of evidence that emerge after the warrant is issued have no bearing on whether or not a warrant was validly issued.9 Just as the discovery of contraband cannot validate a warrant invalid when issued, so is it equally clear that the discovery of facts demonstrating that a valid warrant was unnecessarily broad does not retroactively invalidate the warrant. The validity of the warrant must be assessed on the basis of the information that the officers disclosed, or had a duty to discover and to disclose, to the issuing Magistrate.10 On the basis of that *86information, we agree with the conclusion of all three Maryland courts that the warrant, insofar as it authorized a search that turned out to be ambiguous in scope, was valid when it issued.

II

The question whether the execution of the warrant violated respondent’s constitutional right to be secure in his home is somewhat less clear. We have no difficulty concluding that the officers’ entry into the third-floor common area was legal; they carried a warrant for those premises, and they were accompanied by McWebb, who provided the key that they used to open the door giving access to the third-floor common area. If the officers had known, or should have known, that the third floor contained two apartments before they entered the living quarters on the third floor, and thus had been aware of the error in the warrant, they would have been obligated to limit their search to McWebb’s apart*87ment. Moreover, as the officers recognized, they were required to discontinue the search of respondent’s apartment as soon as they discovered that there were two separate units on the third floor and therefore were put on notice of the risk that they might be in a unit erroneously included within the terms of the warrant. The officers’ conduct and the limits of the search were based on the information available as the search proceeded. While the purposes justifying a police search strictly limit the permissible extent of the search, the Court has also recognized the need to allow some latitude for honest mistakes that are made by officers in the dangerous and difficult process of making arrests and executing search warrants.11

In Hill v. California, 401 U. S. 797 (1971), we considered the validity of the arrest of a man named Miller based on the mistaken belief that he was Hill. The police had probable cause to arrest Hill and they in good faith believed that Miller was Hill when they found him in Hill’s apartment. As we explained:

“The upshot was that the officers in good faith believed Miller was Hill and arrested him. They Were quite wrong as it turned out, and subjective good-faith belief would not in itself justify either the arrest or the subsequent search. But sufficient probability, not certainty, is the touchstone of reasonableness under the Fourth Amendment and on the record before us the officers’ mistake was understandable and the arrest a reasonable response to the situation facing them at the time.” Id., at 803-804.

While Hill involved an arrest without a warrant, its underlying rationale that an officer’s reasonable misidentification *88of a person does not invalidate a valid arrest is equally applicable to an officer’s reasonable failure to appreciate that a valid warrant describes too broadly the premises to be searched. Under the reasoning in Hill, the validity of the search of respondent’s apartment pursuant to a warrant authorizing the search of the entire third floor depends on whether the officers’ failure to realize the overbreadth of the warrant was objectively understandable and reasonable. Here it unquestionably was. The objective facts available to the officers at the time suggested no distinction between McWebb’s apartment and the third-floor premises.12

For that reason, the officers properly responded to the command contained in a valid warrant even if the warrant is interpreted as authorizing a search limited to McWebb’s apartment rather than the entire third floor. Prior to the officers’ discovery of the factual mistake, they perceived McWebb’s apartment and the third-floor premises as one and the same; therefore their execution of the warrant reasonably included the entire third floor.13 Under either interpretation of the warrant, the officers’ conduct was consistent with a reasonable effort to ascertain and identify the place intended to be searched within the meaning of the Fourth Amend*89ment.14 Cf. Steele v. United States, 267 U. S. 498, 503 (1925).

The judgment of the Court of Appeals is reversed, and the case is remanded for further proceedings not inconsistent with this opinion.

It is so ordered.

Justice Blackmun,

with whom Justice Brennan and Justice Marshall join, dissenting.

Under this Court’s precedents, the search of respondent Garrison’s apartment violated the Fourth Amendment. While executing a warrant specifically limited to McWebb’s residence, the officers expanded their search to include re*90spondent’s adjacent apartment, an expansion made without a warrant and in the absence of exigent circumstances. In my view, Maryland’s highest court correctly concluded that the trial judge should have granted respondent’s motion to suppress the evidence seized as a result of this warrantless search of his apartment. Moreover, even if I were to accept the majority’s analysis of this case as one involving a mistake on the part of the police officers, I would find that the officers’ error, either in obtaining or in executing the warrant, was not reasonable under the circumstances.

H-t

The home always has received special protection m analysis under the Fourth Amendment, which protects the “right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures” (emphasis added). See Silverman v. United States, 365 U. S. 505, 511 (1961) (“At the very core [of the Fourth Amendment] stands the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion”). The Fourth Amendment, in fact, was a direct response to the colonists’ objection to searches of homes under general warrants or without warrants. See Chimel v. California, 395 U. S. 752, 761 (1969); Harris v. United States, 331 U. S. 145, 157-163 (1947) (Frankfurter, J., dissenting). In today’s society, the protection of the Amendment of course is extended to the equivalent of the traditional single-family house, such as an apartment. See, e. g., Ker v. California, 374 U. S. 23, 42 (1963).

The Court has observed that, in determining whether one has an interest protected by the Fourth Amendment, it is appropriate not to limit the analysis to the place in question, for “the Fourth Amendment protects people — and not simply ‘areas.’” Katz v. United States, 389 U. S. 347, 353 (1967). As articulated by Justice Harlan in his Katz concurrence, the proper test under the Amendment is whether “a person [has] *91exhibited an actual (subjective) expectation of privacy . . . that society is prepared to recognize as ‘reasonable.’” Id., at 361. Justice Harlan noted, however, that an answer to the question concerning what protection the Fourth Amendment gave to a particular person always “requires reference to a ‘place.’” Ibid. In his view, the home would meet this test in virtually all situations. “[A] man’s home,” he stated, “is, for most purposes, a place where he expects privacy.” Ibid. The home thus has continued to occupy its special role in Fourth Amendment analysis in the post-Aate era. See Payton v. New York, 446 U. S. 573, 585 (1980) (“[T]he ‘physical entry of the home is the chief evil against which the wording of the Fourth Amendment is directed,’” quoting United States v. United States District Court, 407 U. S. 297, 313 (1972)); United States v. Karo, 468 U. S. 705, 714-715 (1984) (“Searches and seizures inside a home without a warrant are presumptively unreasonable absent exigent circumstances”); California v. Carney, 471 U. S. 386, 407-408 (1985) (Stevens, J., dissenting) (“These places [mobile homes] may be as spartan as a humble cottage when compared to the most majestic mansion . . . but the highest and most legitimate expectations of privacy associated with these temporary abodes should command the respect of this Court”); see also Steagald v. United States, 451 U. S. 204, 211 (1981); Coolidge v. New Hampshire, 403 U. S. 443, 477-478 (1971).

The Fourth Amendment also states that “no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized” (emphasis added). The particularity-of-description requirement is satisfied where “the description is such that the officer with a search warrant can with reasonable effort ascertain and identify the place intended.” Steele v. United States, 267 U. S. 498, 503 (1925). In applying this requirement to searches, aimed at residences within multiunit buildings, such as the search in the present case, courts have declared invalid those *92warrants that fail to describe the targeted unit with enough specificity to prevent a search of all the units. See, e. g., United States v. Higgins, 428 F. 2d 232 (CA7 1970); United States v. Votteller, 544 F. 2d 1355, 1362-1363 (CA6 1976). Courts have used different criteria to determine whether a warrant has identified a unit with sufficient particularity. See, e. g., United States v. Bedford, 519 F. 2d 650, 655 (CA3 1975) (by name of occupant of apartment), cert. denied, 424 U. S. 917 (1976); Haynes v. State, 475 S. W. 2d 739, 741 (Tex. Crim. App. 1971) (by directions on how to reach a particular room); see generally 2 W. LaFave, Search and Seizure §4.5, p. 79 (1978); Crais, Sufficiency of Description of Apartment or Room to be Searched in Multiple-Occupancy Structure, 11 A. L. R. 3d 1330, 1340-1341, §5 (1967 and Supp. 1986).

Applying the above principles to this case, I conclude that the search of respondent’s apartment was improper. The words of the warrant were plain and distinctive: the warrant directed the officers to seize marijuana and drug paraphernalia on the person of McWebb and in McWebb’s apartment, i. e., “on the premises known as 2036 Park Avenue third floor apartment.” App. 9. As the Court of Appeals observed, this warrant specifically authorized a search only of Mc-Webb’s — not respondent’s — residence. 303 Md. 385, 392, 494 A. 2d 193, 196 (1985).1 In its interpretation of the war*93rant, the majority suggests that the language of this document, as well as that in the supporting affidavit, permitted a search of the entire third floor. Ante, at 82, and n. 4. It escapes me why the language in question, “third floor apartment,” when used "with reference to a single unit in a multiple-occupancy building and in the context of one person’s residence, plainly has the meaning the majority discerns, rather than its apparent and, indeed, obvious signification — one apartment located on the third floor.2 Accordingly, if, as appears to be the case, the warrant was limited in its description to the third-floor apartment of McWebb, then the search of an additional apartment — respondent’s—was war-rantless and is presumed unreasonable “in the absence of some one of a number of well defined ‘exigent circumstances.’” Coolidge v. New Hampshire, 403 U. S., at 478. Because the State has not advanced any such exception to the warrant requirement, the evidence obtained as a result of this search should have been excluded.3

*941 — I

Because the Court cannot justify the officers search under the “exceptional circumstances” rubric, it analyzes the police conduct here in terms of “mistake.” According to the Court, hindsight makes it clear that the officers were mistaken, first, in not describing McWebb’s apartment with greater specificity in the warrant, ante, at 85, and, second, in including respondent’s apartment within the scope of the execution of the warrant, ante, at 86-87. The Court’s inquiry focuses on what the officers knew or should have known at these particular junctures. The Court reasons that if, in light of the officers’ actual or imputed knowledge, their behavior was reasonable, then their mistakes did not constitute an infringement on respondent’s Fourth Amendment rights. In this case, the Court finds no Fourth Amendment violation because the officers could not reasonably have drawn the warrant with any greater particularity and because, until the moment when the officers realized that they were in fact searching two different apartments, they had no reason to believe that McWebb’s residence did not cover the entire third floor.

The majority relies upon Hill v. California, 401 U. S. 797 (1971), for its conclusion that “honest mistakes” in arrests or searches may obviate Fourth Amendment problems. Ante, at 87-88. It is doubtful whether Hill carries the preceden-tial weight that the majority would ascribe to it. Decided after Chimel v. California, 395 U. S. 752 (1969), but involving a pre-Chimel incident, Hill presented a situation where officers, who had probable cause but no warrant to arrest *95Hill, went to Hill’s apartment and found Miller instead. 401 U. S., at 799. They mistook Miller for Hill, despite the former’s protestations to the contrary, and conducted a search of Hill’s apartment, which produced the only substantial evidence later used to convict Hill for robbery. Id., at 801. In deciding that neither the arrest nor the ensuing search constituted a Fourth Amendment violation, the Court was entertaining a challenge made by Hill. The Court here, however, is faced with a Fourth Amendment claim brought by respondent, whose position is comparable to that of Miller. It may make some sense to excuse a reasonable mistake by police that produces evidence against the intended target of an investigation or warrant if the officers had probable cause for arresting that individual or searching his residence. Similar reasoning does not apply with respect to one whom probable cause has not singled out and who is the victim of the officers’ error. See Brinegar v. United States, 338 U. S. 160, 176 (1949) (“These long-prevailing standards [of probable cause] seek to safeguard citizens from rash and unreasonable interferences with privacy and from unfounded charges of crime”); cf. Ybarra v. Illinois, 444 U. S. 85, 91 (1979) (“But, a person’s mere propinquity to others independently suspected of criminal activity does not, without more, give rise to probable cause to search that person. . . . This requirement [of probable cause] cannot be undercut or avoided by simply pointing to the fact that coincidentally there exists probable cause to search or seize another or to search the premises where the person may happen to be”).

Even if one accepts the majority’s view that there is no Fourth Amendment violation where the officers’ mistake is reasonable,4 it is questionable whether that standard was *96met in this case. To repeat Justice Harlan’s observation, although the proper question in Fourth Amendment analysis is “what protection it affords to . . . people,. . . that question requires reference to a ‘place.’” Katz v. United States, 389 U. S., at 361 (concurring opinion). The “place” at issue here is a small multiple-occupancy building. Such forms of habitation are now common in this country, particularly in neighborhoods with changing populations and of declining affluence.5 Accordingly, any analysis of the “reasonableness” of *97the officers’ behavior here must be done with this context in mind.

The efforts of Detective Marcus, the officer who procured the search warrant, do not meet a standard of reasonableness, particularly considering that the detective knew the search concerned a unit in a multiple-occupancy building. See App. 34. Upon learning from his informant that Mc-Webb was selling marijuana in his third-floor apartment, Marcus inspected the outside of the building. Id., at 35. He did not approach it, however, to gather information about the configuration of the apartments. Ibid. Had he done so, he would have discovered, as did another officer on the day of executing the warrant, id., at 13, that there were seven separate mailboxes and bells on the porch outside the main entrance to the house. Although there is some dispute over whether names were affixed near these boxes and bells, id., at 13-14; Suppression Hearing Tr. M2-96 to M2-97, their existence alone puts a reasonable observer on notice that the three-story structure (with, possibly, a basement) had seven individual units. The detective, therefore, should have been aware that further investigation was necessary to eliminate the possibility of more than one unit’s being located on the third floor. Moreover, when Detective Marcus’ informant told him that he had purchased drugs in McWebb’s apartment, App. 6, it appears that the detective never thought to ask the informant whether McWebb’s apartment was the only one on the third floor. These efforts, which would have placed a slight burden upon the detective, are necessary in order to render reasonable the officer’s behavior in seeking the warrant.6

*98Moreover, even if one believed that Marcus’ efforts in providing information for issuance of the warrant were reasonable, I doubt whether the officers’ execution of the warrant could meet such a standard. In the Court’s view, the “objective facts” did not put the officers on notice that they were dealing with two separate apartments on the third floor until the moment, considerably into the search after they had rummaged through a dresser and a closet in respondent’s apartment and had discovered evidence incriminating him, when they realized their “mistake.” Ante, at 80, 88-89. The Court appears to base its conclusion that the officers’ error here was reasonable on the fact that neither McWebb nor re*99spondent ever told the officers during the search that they lived in separate apartments. See ante, at 88, n. 12.

In my view, however, the “objective facts” should have made the officers aware that there were two different apartments on the third floor well before they discovered the incriminating evidence in respondent’s apartment. Before McWebb happened to drive up while the search party was preparing to execute the warrant, one of the officers, Detective Shea, somewhat disguised as a construction worker, was already on the porch of the row house and was seeking to gain access to the locked first-floor door that permitted entrance into the building. App. 13.7 From this vantage point he had time to observe the seven mailboxes and bells; indeed, he rang all seven bells, apparently in an effort to summon some resident to open the front door to the search party. Id., at 13, 15. A reasonable officer in Detective Shea’s position, already aware that this was a multiunit building and now armed with further knowledge of the number of units in the structure, would have conducted at that time more investigation to specify the exact location of Mc-Webb’s apartment before proceeding further. For example, he might have questioned another resident of the building.

It is surprising, moreover, that the Court places so much emphasis on the failure of McWebb to volunteer information about the exact location of his apartment. When McWebb drove up, one of the police vehicles blocked his car and the officers surrounded him and his passenger as they got out. Suppression Hearing Tr. M2-15, M2-56, M2-130 to M2-131. Although the officers had no arrest warrant for McWebb, but only a search warrant for his person and apartment,8 and al*100though they testified that they did not arrest him at that time, id., at M2-14, M2-60,9 it was clear that neither Mc-Webb nor his passenger was free to leave. See App. 42, Suppression Hearing Tr. M2-157 to M2-158. In such circumstances, which strongly suggest that McWebb was already in custody, it was proper for the officers to administer to him warnings pursuant to Miranda v. Arizona, 384 U. S. 436 (1966). It would then have been reasonable for the officers, aware of the problem, from Detective Shea’s discovery, in the specificity of their warrant, to ask McWebb whether his apartment was the only one on the third floor.10 As it is, the officers made several requests of and questioned Mc-Webb, without giving him Miranda warnings, and yet failed to ask him the question, obvious in the circumstances, concerning the exact location of his apartment. Suppression Hearing Tr. M2-60, M2-131, M2-157.

Moreover, a reasonable officer would have realized the mistake in the warrant during the moments following the officers’ entrance to the third floor. The officers gained access to the vestibule separating McWebb’s and respondent’s apartments through a locked door for which McWebb supplied the key. App. 17. There, in the open doorway to his apartment, they encountered respondent, clad in pajamas and wearing a half-body cast as a result of a recent spinal operation. Id., at 16; Suppression Hearing Tr. M2-104 to M2-105. Although the facts concerning what next occurred are somewhat in dispute, see id., at M2-108, M2-167, it appears that respondent, together with McWebb and the passenger from McWebb’s car, were shepherded into McWebb’s *101apartment across the vestibule from his own. Once again, the officers were curiously silent. The informant had not led the officers to believe that anyone other than McWebb lived in the third-floor apartment; the search party had McWebb, the person targeted by the search warrant, in custody when it gained access to the vestibule; yet when they met respondent on the third floor, they simply asked him who he was but never where he lived. Id., at M2-165. Had they done so, it is likely that they would have discovered the mistake in the warrant before they began their search.

Finally and most importantly, even if the officers had learned nothing from respondent, they should have realized the error in the warrant from their initial security sweep. Once on the third floor, the officers first fanned out through the rooms to conduct a preliminary check for other occupants who might pose a danger to them. Id., at M2-63, M2-74, M2-87, M2-167. As the map of the third floor demonstrates, see 303 Md., at 396, 494 A. 2d, at 199, the two apartments were almost a mirror image of each other — each had a bathroom, a kitchen, a living room, and a bedroom. Given the somewhat symmetrical layout of the apartments, it is difficult to imagine that, in the initial security sweep, a reasonable officer would not have discerned that two apartments were on the third floor, realized his mistake, and then confined the ensuing search to McWebb’s residence.11

Accordingly, even if a reasonable error on the part of police officers prevents a Fourth Amendment violation, the mistakes here, both with respect to obtaining and executing the warrant, are not reasonable and could easily have been avoided.

I respectfully dissent.

Justice Stevens

delivered the opinion of the Court.

In Wilson v. Arkansas, 514 U. S. 927 (1995), we held that the Fourth Amendment incorporates the common-law requirement that police officers entering a dwelling must knock on the door and announce their identity and purpose before attempting forcible entry. At the same time, we recognized that the “flexible requirement of reasonableness should not be read to mandate a rigid rule of announcement that ignores countervailing law enforcement interests,” id., at 934, and left “to the lower courts the task of determining the circumstances under which an unannounced entry is reasonable under the Fourth Amendment,” id., at 936.

In this case, the Wisconsin Supreme Court concluded that police officers are never required to knock and announce their presence when executing a search warrant in a felony *388drug investigation. In so doing, it reaffirmed a pre-Wilson holding and concluded that Wilson did not preclude this per se rule. We disagree with the court’s conclusion that the Fourth Amendment permits a blanket exception to the knock-and-announce requirement for this entire category of criminal activity. But because the evidence presented to support the officers’ actions in this case establishes that the decision not to knock and announce was a reasonable one under the circumstances, we affirm the judgment of the Wisconsin court.

I

On December 31, 1991, police officers in Madison, Wisconsin, obtained a warrant to search Steiney Richards’ motel room for drugs and related paraphernalia. The search warrant was the culmination of an investigation that had uncovered substantial evidence that Richards was one of several individuals dealing drugs out of hotel rooms in Madison. The police requested a warrant that would have given advance authorization for a “no-knock” entry into the motel room, but the Magistrate explicitly deleted those portions of the warrant. App. 7, 9.

The officers arrived at the motel room at 3:40 a.m. Officer Pharo, dressed as a maintenance man, led the team. With him were several plainclothes officers and at least one man in uniform. Officer Pharo knocked on Richards’ door and, responding to the query from inside the room, stated that he was a maintenance man. With the chain still on the door, Richards cracked it open. Although there is some dispute as to what occurred next, Richards acknowledges that when he opened the door he saw the man in uniform standing behind Officer Pharo. Brief for Petitioner 6. He quickly slammed the door closed and, after waiting two or three seconds, the officers began kicking and ramming the door to gain entry to the locked room. At trial, the officers testified that they identified themselves as police while they were kicking the door in. App. 40. When they finally did break *389into the room, the officers caught Richards trying to escape through the window. They also found cash and cocaine hidden in plastic bags above the bathroom ceiling tiles.

Richards sought to have the evidence from his motel room suppressed on the ground that the officers had failed to knock and announce their presence prior to forcing entry into the room. The trial court denied the motion, concluding that the officers could gather from Richards’ strange behavior when they first sought entry that he knew they were police officers and that he might try to destroy evidence or to escape. Id., at 54. The judge emphasized that the easily disposable nature of the drugs the police were searching for further justified their decision to identify themselves as they crossed the threshold instead of announcing their presence before seeking entry. Id., at 55. Richards appealed the decision to the Wisconsin Supreme Court and that court affirmed. 201 Wis. 2d 845, 549 N. W. 2d 218 (1996).

The Wisconsin Supreme Court did not delve into the events underlying Richards’ arrest in any detail, but accepted the following facts: “[0]n December 31, 1991, police executed a search warrant for the motel room of the defendant seeking evidence of the felonious crime of Possession with Intent to Deliver a Controlled Substance in violation of Wis. Stat. § 161.41(lm) (1991-92). They did not knock and announce prior to their entry. Drugs were seized.” Id., at 849, 549 N. W. 2d, at 220.

Assuming these facts, the court proceeded to consider whether our decision in Wilson required the court to abandon its decision in State v. Stevens, 181 Wis. 2d 410, 511 N. W. 2d 591 (1994), cert. denied, 515 U. S. 1102 (1995), which held that “when the police have a search warrant, supported by probable cause, to search a residence for evidence of delivery of drugs or evidence of possession with intent to deliver drugs, they necessarily have reasonable cause to believe exigent circumstances exist” to justify a no-knock entry. 201 Wis. 2d, at 852, 549 N. W. 2d, at 221. The court concluded *390that nothing in Wilson’s acknowledgment that the knock- and-announce rule was an element of the Fourth Amendment “reasonableness” requirement would prohibit application of a per se exception to that rule in a category of cases. 201 Wis. 2d, at 854-855, 549 N. W. 2d, at 220.

In reaching this conclusion, the Wisconsin court found it reasonable — after considering criminal conduct surveys, newspaper articles, and other judicial opinions — to assume that all felony drug crimes will involve “an extremely high risk of serious if not deadly injury to the police as well as the potential for the disposal of drugs by the occupants prior to entry by the police.” Id., at 847-848, 549 N. W. 2d, at 219. Notwithstanding its acknowledgment that in “some cases, police officers will undoubtedly decide that their safety, the safety of others, and the effective execution of the warrant dictate that they knock and announce,” id., at 863, 549 N. W. 2d, at 225, the court concluded that exigent circumstances justifying a no-knock entry are always present in felony drug cases. Further, the court reasoned that the violation of privacy that occurs when officers who have a search warrant forcibly enter a residence without first announcing their presence is minimal, given that the residents would ultimately be without authority to refuse the police entry. The principal intrusion on individual privacy interests in such a situation, the court concluded, comes from the issuance of the search warrant, not the manner in which it is executed. Id., at 864-865, 549 N. W. 2d, at 226. Accordingly, the court determined that police in Wisconsin do not need specific information about dangerousness, or the possible destruction of drugs in a particular case, in order to dispense with the knock-and-announce requirement in felony drug cases.1

*391Justice Abrahamson concurred in the judgment because, in her view, the facts found by the trial judge justified a no-knock entry. Id,., at 866-868, 549 N. W. 2d, at 227. Specifically, she noted that Richards’ actions in slamming the door when he saw the uniformed man standing behind Officer Pharo indicated that he already knew that the people knocking on his door were police officers. Under these circumstances, any further announcement of their presence would have been a useless gesture. Id., at 868-869, n. 3, 549 N. W. 2d, at 228, n. 3. While agreeing with the outcome, Justice Abrahamson took issue with her colleagues’ affirmation of the blanket exception to the knock-and-announce requirement in drug felony cases. She observed that the constitutional reasonableness of a search has generally been a matter left to the court, rather than to the officers who conducted the search, and she objected to the creation of a blanket rule that insulated searches in a particular category of crime from the neutral oversight of a reviewing judge. Id., at 868-875, 549 N. W. 2d, at 228-230.

II

We recognized in Wilson that the knock-and-announce requirement could give way “under circumstances presenting a threat of physical violence,” or “where police officers have reason to believe that evidence would likely be destroyed if advance notice were given.” 514 U. S., at 936. It is indisputable that felony drug investigations may frequently involve both of these circumstances.2 The question we must *392resolve is whether this fact justifies dispensing with case-by-case evaluation of the manner in which a search was executed.3

The Wisconsin court explained its blanket exception as necessitated by the special circumstances of today’s drug culture, 201 Wis. 2d, at 863-866, 549 N. W. 2d, at 226-227, and the State asserted at oral argument that the blanket exception was reasonable in “felony drug cases because of the convergence in a violent and dangerous form of commerce of weapons and the destruction of drugs.” Tr. of Oral Arg. 26. But creating exceptions to the knock-and-announce rule based on the “culture” surrounding a general category of criminal behavior presents at least two serious concerns.4

*393First, the exception contains considerable overgeneralization. For example, while drug investigation frequently does pose special risks to officer safety and the preservation of evidence, not every drug investigation will pose these risks to a substantial degree. For example, a search could be conducted at a time when the only individuals present in a residence have no connection with the drug activity and thus will be unlikely to threaten officers or destroy evidence. Or the police could know that the drugs being searched for were of a type or in a location that made them impossible to destroy quickly. In those situations, the asserted governmental interests in preserving evidence and maintaining safety may not outweigh the individual privacy interests intruded upon by a no-knock entry.5 Wisconsin’s blanket rule imper-missibly insulates these cases from judicial review.

A second difficulty with permitting a criminal-category exception to the knock-and-announce requirement is that the *394reasons for creating an exception in one category can, relatively easily, be applied to others. Armed bank robbers, for example, are, by definition, likely to have weapons, and the fruits of their crime may be destroyed without too much difficulty. If a per se exception were allowed for each category of criminal investigation that included a considerable — albeit hypothetical — risk of danger to officers or destruction of evidence, the knock-and-announce element of the Fourth Amendment’s reasonableness requirement would be meaningless.

Thus, the fact that felony drug investigations may frequently present circumstances warranting a no-knock entry cannot remove from the neutral scrutiny of a reviewing court the reasonableness of the police decision not to knock and announce in a particular case. Instead, in each case, it is the duty of a court confronted with the question to determine whether the facts and circumstances of the particular entry justified dispensing with the knock-and-announce requirement.

In order to justify a “no-knock” entry, the police must have a reasonable suspicion that knocking and announcing their presence, under the particular circumstances, would be dangerous or futile, or that it would inhibit the effective investigation of the crime by, for example, allowing the destruction of evidence. This standard — as opposed to a probable-cause requirement — strikes the appropriate balance between the legitimate law enforcement concerns at issue in the execution of search warrants and the individual privacy interests affected by no-knock entries. Cf. Maryland v. Buie, 494 U. S. 325, 337 (1990) (allowing a protective sweep of a house during an arrest where the officers have “a reasonable belief based on specific and articulable facts that the area to be swept harbors an individual posing a danger to those on the arrest scene”); Terry v. Ohio, 392 U. S. 1, 30 (1968) (requiring a reasonable and articulable suspicion of danger to justify a patdown search). This showing is not high, but the police *395should be required to make it whenever the reasonableness of a no-knock entry is challenged.

III

Although we reject the Wisconsin court’s blanket exception to the knock-and-announce requirement, we conclude that the officers’ no-knock entry into Richards’ motel room did not violate the Fourth Amendment. We agree with the trial court, and with Justice Abrahamson, that the circumstances in this case show that the officers had a reasonable suspicion that Richards might destroy evidence if given further opportunity to do so.6

The judge who heard testimony at Richards’ suppression hearing concluded that it was reasonable for the officers executing the warrant to believe that Richards knew, after opening the door to his motel room the first time, that the men seeking entry to his room were the police. App. 54. Once the officers reasonably believed that Richards knew who they were, the court concluded, it was reasonable for them to force entry immediately given the disposable nature of the drugs. Id., at 55.

In arguing that the officers’ entry was unreasonable, Richards places great emphasis on the fact that the Magistrate who signed the search warrant for his motel room deleted the portions of the proposed warrant that would have given the officers permission to execute a no-knock entry. But this fact does not alter the reasonableness of the officers’ decision, which must be evaluated as of the time they entered the motel room. At the time the officers obtained the warrant, they did not have evidence sufficient, in the judgment of the Magistrate, to justify a no-knock warrant. Of course, *396the Magistrate could not have anticipated in every particular the circumstances that would confront the officers when they arrived at Richards’ motel room.7 These actual circumstances — petitioner’s apparent recognition of the officers combined with the easily disposable nature of the drugs— justified the officers’ ultimate decision to enter without first announcing their presence and authority.

Accordingly, although we reject the blanket exception to the knock-and-announce requirement for felony drug investigations, the judgment of the Wisconsin Supreme Court is affirmed.

It is so ordered.

Mr. Justice Stewart

delivered the opinion of the Court.

It is well settled under the Fourth and Fourteenth Amendments that a search conducted without a warrant issued upon probable cause is “per se unreasonable . . . subject only to a few specifically established and well-delineated exceptions.” Katz v. United States, 389 U. S. 347, 357; Coolidge v. New Hampshire, 403 U. S. 443, 454-455; Chambers v. Maroney, 399 U. S. 42, 51. It is equally well settled that one of the specifically established exceptions to the requirements of both a warrant and probable cause is a search that is conducted pursuant to consent. Davis v. United States, 328 U. S. 582, 593-594; Zap v. United States, 328 U. S. 624, 630. The constitutional question in the present case concerns the definition of “consent” in this Fourth and Fourteenth Amendment context.

I

The respondent was brought to trial in a California court upon a charge of possessing a check with intent to defraud.1 He moved to suppress the introduction of certain material as evidence against him on the ground that the material had been acquired through an unconstitutional search and seizure. In response to the motion, the trial judge conducted an evidentiary hearing *220where it was established that the material in question had been acquired by the State under the following circumstances:

While on routine patrol in Sunnyvale, California, at approximately 2:40 in the morning, Police Officer James Rand stopped an automobile when he observed that one headlight and its license plate light were burned out. Six men were in the vehicle. Joe Alcala and the respondent, Robert Bustamonte, were in the front seat with Joe Gonzales, the driver. Three older men were seated in the rear. When, in response to the policeman's question, Gonzales could not produce a driver’s license, Officer Rand asked if any of thé other five had any evidence of identification. Only Alcala produced a license, and he explained that the car was his brother’s. After the six occupants had stepped out of the car at the officer’s request and after two additional policemen had arrived, Officer Rand asked Alcala if he could search the car. Alcala replied, “Sure, go ahead.” Prior to the search no one was threatened with arrest and, according to Officer Rand’s uncontradicted testimony, it “was all very congenial at this time.” Gonzales testified that Alcala actually helped in the search of the car, by opening the trunk and glove compartment. In Gonzales’ words: “[T]he police officer asked Joe [Alcala], he goes, 'Does the trunk open?’ And Joe said, 'Yes.’ He went to the car and got the keys and opened up the trunk.” Wadded up under the left rear seat, the police officers found three checks that had previously been stolen from a car wash.

The trial judge denied the motion to suppress, and the checks in question were admitted in evidence ar Bustamonte’s trial. On the basis of this and other evidence he was convicted, and the California Court of Appeal for the First Appellate District affirmed the convic*221tion. 270 Cal. App. 2d 648, 76 Cal. Rptr. 17. In agreeing that the search and seizure were constitutionally valid, the appellate court applied the standard earlier formulated by the Supreme Court of California in an opinion by then Justice Traynor: “Whether in a particular case an apparent consent was in fact voluntarily given or was in submission to an express or implied assertion of authority, is a question of fact to be determined in the light of all the circumstances.” People v. Michael, 45 Cal. 2d 751, 753, 290 P. 2d 852, 854. The appellate court-found that “[i]n the instant case the prosecution met the necessary burden of showing consent . . . since there were clearly circumstances from which the trial court could ascertain that consent had been freely given without coercion or submission to authority. Not only officer Rand, but Gonzales, the driver of the automobile, testified that Alcala’s assent to the search of his brother’s automobile was freely, even casually given. At the time of the request to search the automobile the atmosphere, according to Rand, was ‘congenial’ and there had been no discussion of any crime. As noted, Gonzales said Alcala even attempted to aid in the search.” 270 Cal. App. 2d, at 652, 76 Cal. Rptr., at 20. The California Supreme Court denied review.2

Thereafter, the respondent sought a writ of habeas corpus in a federal district court. It was denied.3 On appeal, the Court of Appeals for the Ninth Circuit, relying on its prior decisions in Ciprés v. United States, 343 F. 2d 95, and Schoepflin v. United States, 391 F. 2d 390, set aside the District Court’s order. 448 F. 2d 699. The appellate court reasoned that a consent was a waiver of a person’s Fourth and Fourteenth Amendment rights, and that the State was under an obligation to demon*222strate, not only that the consent had been uncoerced, but that it had been given with an understanding that it could be freely and effectively withheld. Consent could not be found, the court held, solely from the absence of coercion and a verbal expression of assent. Since the District Court had not determined that Alcala had known that his consent could have been withheld and that he could have refused to have his vehicle searched, the Court of Appeals vacated the order denying the writ and remanded the case for further proceedings. We granted certiorari to determine whether the Fourth and Fourteenth Amendments require the showing thought necessary by the Court of Appeals. 405 U. S. 953.

II

It is important to make it clear at the outset what is not involved in this case. The respondent concedes that a search conducted pursuant to a valid consent is constitutionally permissible. In Katz v. United States, 389 U. S., at 358, and more recently in Vale v. Louisiana, 399 U. S. 30, 35, we recognized that a search authorized by consent is wholly valid. See also Davis v. United States, 328 U. S., at 593-594; Zap v. United States, 328 U. S., at 630.4 And similarly the State concedes that “[w]hen a prosecutor seeks to rely upon consent to justify the lawfulness of a search, he has the burden of proving that the consent was, in fact, freely and voluntarily given1.” Bumper v. North Carolina, 391 U. S. 543, 548. See also Johnson v. United States, 333 U. S. 10; Amos v. United States, 255 U. S. 313.

*223The precise question in this case, then, is what must the prosecution prove to demonstrate that a consent was “voluntarily” given. And upon that question there is a square conflict of views between the state and federal courts that have reviewed the search involved in the case before us. The Court of Appeals for the Ninth Circuit concluded that it is an essential part of the State’s initial burden to prove that a person knows he has a right to refuse consent. The California courts have followed the rule that voluntariness is a question of fact to be determined from the totality of all the circumstances, and that the state of a defendant’s knowledge is only one factor to be taken into account in assessing the voluntariness of a consent. See, e. g., People v. Tremayne, 20 Cal. App. 3d 1006, 98 Cal. Rptr. 193; People v. Roberts, 246 Cal. App. 2d 715, 55 Cal. Rptr. 62.

A

The most extensive judicial exposition of the meaning of “voluntariness” has been developed in those cases in which the Court has had to determine the “voluntariness” of a defendant’s confession for purposes of the Fourteenth Amendment. Almost 40 years ago, in Brown v. Mississippi, 297 U. S. 278, the Court held that a criminal conviction based upon a confession obtained by brutality and violence was constitutionally invalid under the Due Process Clause of the Fourteenth Amendment. In some 30 different cases decided during the era that intervened between Brown and Escobedo v. Illinois, 378 U. S. 478, the Court was faced with the necessity of determining whether in fact the confessions in issue had been “voluntarily” given.5 It is to that body *224of case law to which we turn for initial guidance on the meaning of “voluntariness” in the present context.6

Those cases yield no talismanic definition of “volun-tariness,” mechanically applicable to the host of situations where the question has arisen. “The notion of ‘voluntariness,’ ” Mr. Justice Frankfurter once wrote, “is itself an amphibian.” Culombe v. Connecticut, 367 U. S. 568, 604-605. It cannot be taken literally to mean a “knowing” choice. “Except where a person is unconscious or drugged or otherwise lacks capacity for conscious choice, all incriminating statements — even those made under brutal treatment — are ‘voluntary’ in the sense of representing a choice of alternatives. On the other hand, if ‘voluntariness’ incorporates notions of ‘but-for’ cause, the question should be whether the statement would have been made even absent inquiry or other official action. Under such a test, virtually no statement would be voluntary because very few people give incriminating statements in the absence of official action of some kind.” 7 It is thus evident that neither linguistics nor epistemology will provide a ready definition of the meaning of “voluntariness.”

Rather, “voluntariness” has reflected an accommodation of the complex of values implicated in police ques*225tioning of a suspect. At one end of the spectrum is the acknowledged need for police questioning as a tool for the effective enforcement of criminal laws. See Culombe v. Connecticut, supra, at 578-580. Without such investigation, those who were innocent might be falsely accused, those who were guilty might wholly escape prosecution, and many crimes would go unsolved. In short, the security of all would be diminished. Haynes v. Washington, 373 U. S. 503, 515. At the other end of the spectrum is the set of values reflecting society’s deeply felt belief that the criminal law cannot be used as an instrument of unfairness, and that the possibility of unfair and even brutal police tactics poses a real and serious threat to civilized notions of justice. “[I]n cases involving involuntary confessions, this Court enforces the strongly felt attitude of our society that important human values are sacrificed where an agency of the government, in the course of securing a conviction, wrings a confession out of an accused against his will.” Blackburn v. Alabama, 361 U. S. 199, 206-207. See also Culombe v. Connecticut, supra, at 581-584; Chambers v. Florida, 309 U. S. 227, 235-238.

This Court’s decisions reflect a frank recognition that the Constitution requires the sacrifice of neither security nor liberty. The Due Process Clause does not mandate that the police forgo all questioning, or that they be given carte blanche to extract what they can from a suspect. “The ultimate test remains that which has been the only clearly established test in Anglo-American courts for two hundred years: the test of voluntariness. Is the confession the product of an essentially free and unconstrained choice by its maker? If it is, if he has willed to confess, it may be used against him. If it is not, if his will has been overborne and his capacity for self-determination critically impaired, the use of his *226confession offends due process.” Culombe v. Connecticut, supra, at 602.

In determining whether a defendant’s will was overborne in a particular case, the Court has assessed the totality of all the surrounding circumstances — both the characteristics of the accused and the details of the interrogation. Some of the factors taken into account have included the youth of the accused, e. g., Haley v. Ohio, 332 U. S. 596; his lack of education, e. g., Payne v. Arkansas, 356 U. S. 560; or his low intelligence, e. g., Fikes v. Alabama, 352 U. S. 191; the lack of any advice to the accused of his constitutional rights, e. g., Davis v. North Carolina, 384 U. S. 737; the length of detention, e. g., Chambers v. Florida, supra; the repeated and prolonged nature of the questioning, e. g., Ashcraft v. Tennessee, 322 U. S. 143; and the use of physical punishment such as the deprivation of food or sleep, e. g., Reck v. Pate, 367 U. S. 433.8 In all of these cases, the Court determined the factual circumstances surrounding the confession, assessed the psychological impact on the accused, and evaluated the legal significance of how the accused reacted. Culombe v. Connecticut, supra, at 603.

The significant fact about all of these decisions is that none of them turned on the presence or absence of a single controlling criterion; each reflected a careful scrutiny of all the surrounding circumstances. See Miranda v. Arizona, 384 U. S. 436, 508 (Harlan, J., dissenting) ; id., at 534-535 (White, J., dissenting). In none of them did the Court rule that the Due Process Clause required the prosecution to prove as part of its *227initial burden that the defendant knew he had a right to refuse to answer the questions that were put. While the state of the accused's mind, and the failure of the police to advise the accused of his rights, were certainly factors to be evaluated in assessing the “voluntariness” of an accused's responses, they were not in and of themselves determinative. See, e. g., Davis v. North Carolina, supra; Haynes v. Washington, supra, at 510-511; Culombe v. Connecticut, supra, at 610; Turner v. Pennsylvania, 338 U. S. 62, 64.

B

Similar considerations lead us to agree with the courts of California that the question whether a consent to a search was in fact “voluntary” or was the product of duress or coercion, express or implied, is a question of fact to be determined from the totality of all the circumstances. While knowledge of the right to refuse consent is one factor to be taken into account, the government need not establish such knowledge as the sine qua non of an effective consent. As with police questioning, two competing concerns must be accommodated in determining the meaning of a “voluntary” consent — the legitimate need for such searches and the equally important requirement of assuring the absence of coercion.

In situations where the police have some evidence of illicit activity, but lack probable cause to arrest or search, a search authorized by a valid consent may be the only means of obtaining important and reliable evidence.9 In the present case for example, while the police had reason to stop the car for traffic violations, the State does not contend that there was probable cause to search the vehicle or that the search was incident to a valid arrest *228of any of the occupants.10 Yet, the search yielded tangible evidence that served as a basis for a prosecution, and provided some assurance that others, wholly innocent of the crime, were not mistakenly brought to trial. And in those cases where there is probable cause to arrest or search, but where the police lack a warrant, a consent search may still be valuable. If the search is conducted and proves fruitless, that in itself may convince the police that an arrest with its possible stigma and embarrassment is unnecessary, or that a far more extensive search pursuant to a warrant is not justified. In short, a search pursuant to consent may result in considerably less inconvenience for the subject of the search, and, properly conducted, is a constitutionally permissible and wholly legitimate aspect of effective police activity.

But the Fourth and Fourteenth Amendments require that a consent not be coerced, by explicit or implicit means, by implied threat.or covert force. For, no matter how subtly the coercion was applied, the resulting “consent” would be no more than a pretext for the unjustified police intrusion against which the Fourth Amendment is directed. In the words of the classic admonition in Boyd v. United States, 116 U. S. 616, 635:

“It may be that it is the obnoxious thing in its mildest and least repulsive form; but illegitimate and unconstitutional practices get their first footing in that way, namely, by silent approaches and slight deviations from legal modes of procedure. This can only be obviated by adhering to the rule that constitutional provisions for the security of person and property should be liberally construed. A close *229and literal construction 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 encroachments thereon.”

The problem of reconciling the recognized legitimacy of consent searches with the requirement that they be free from any aspect of official coercion cannot be resolved by any infallible touchstone. To approve such searches without the most careful scrutiny would sanction the possibility of official coercion; to place artificial restrictions upon such searches would jeopardize their basic validity. Just as was true with confessions, the requirement of a “voluntary” consent reflects a fair accommodation of the constitutional requirements involved. In examining all the surrounding circumstances to determine if in fact the consent to search was coerced, account must be taken of subtly coercive police questions, as well as the possibly vulnerable subjective state of the person who consents. Those searches that are the product of police coercion can thus be filtered out without undermining the continuing validity of consent searches. In sum, there is no reason for us to depart in the area of consent searches, from the traditional definition of “voluntariness.”

The approach of the Court of Appeals for the Ninth Circuit finds no support in any of our decisions that have attempted to define the meaning of “voluntariness.” Its ruling, that the State must affirmatively prove that the subject of the search knew that he had a right to refuse consent, would, in practice, create serious doubt whether consent searches could continue to be conducted. There might be rare cases where it could be proved from the record that a person in fact affirmatively knew of his *230right to refuse — such as a case where he announced to the police that if he didn't sign the consent form, “you [police] are going to get a search warrant;” 11 or a case where by prior experience and training a person had clearly and convincingly demonstrated such knowledge.12 But more commonly where there was no evidence of any coercion, explicit or implicit, the prosecution would nevertheless be unable to demonstrate that the subject of the search in fact had known of his right to refuse consent.

The very object of the inquiry — the nature of a person's subjective understanding — underlines the difficulty of the prosecution's burden under the rule applied by the Court of Appeals in this case. Any defendant who was the subject of a search authorized solely by his consent could effectively frustrate the introduction into evidence of the fruits of that search by simply failing to testify that he in fact knew he could refuse to consent. And the near impossibility of meeting this prosecutorial burden suggests why this Court has never accepted any such litmus-paper test of voluntariness. It is instructive to recall the fears of then Justice Traynor of the California Supreme Court:

“[I]t is not unreasonable for officers to seek interviews with suspects or witnesses or to call upon them at their homes for such purposes. Such inquiries, although courteously made and not accompanied with any assertion of a right to enter or search or secure answers, would permit the criminal to defeat his prosecution by voluntarily revealing all of the evidence against him and then contending that he acted only in response to an implied assertion of *231unlawful authority.” People v. Michael, 45 Cal. 2d, at 754, 290 P. 2d, at 854.

One alternative that would go far toward proving that the subject of a search did know he had a right to refuse consent would be to advise him of that right before eliciting his consent. That, however, is a suggestion that has been almost universally repudiated by both federal13 and state courts,14 and, we think, rightly so. For it would be thoroughly impractical to impose on the normal consent search the detailed requirements of an effective warning. Consent searches are part of the standard investigatory techniques of law enforcement *232agencies. They normally occur on the highway, or in a person’s home or office, and under informal and unstructured conditions. The circumstances that prompt the initial request to search may develop quickly or be a logical extension of investigative police questioning. The police may seek to investigate further suspicious circumstances or to follow up leads developed in questioning persons at the scene of a crime. These situations are a far cry from the structured atmosphere of a trial where, assisted by counsel if he chooses, a defendant is informed of his trial rights. Cf. Boykin v. Alabama, 395 U. S. 238, 243. And, while surely a closer question, these situations are still immeasurably far removed from “custodial interrogation” where, in Miranda v. Arizona, supra, we found that the Constitution required certain now familiar warnings as a prerequisite to police interrogation. Indeed, in language applicable to the typical consent search, we refused to extend the need for warnings:

“Our decision is not intended to hamper the traditional function of police officers in investigating crime. . . . When an individual is in custody on probable cause, the police may, of course, seek out evidence in the field to be used at trial against him. Such investigation may include inquiry of persons not under restraint. General on-the-scene questioning as to facts surrounding a crime or other general questioning of citizens in the fact-finding process is not affected by our holding. It is an act of responsible citizenship for individuals to give whatever information they may have to aid in law enforcement.” 384 U. S., at 477-478.

Consequently, we cannot accept the position of the Court of Appeals in this case that proof of knowledge of the right to refuse consent is a necessary prerequisite *233to demonstrating a “voluntary” consent. Rather, it is only by analyzing all the circumstances of an individual consent that it can be ascertained whether in fact it was voluntary or coerced. It is this careful sifting of the unique facts and circumstances of each case that is evidenced in our prior decisions involving consent searches.

For example, in Davis v. United States, 328 U. S. 582, federal agents enforcing wartime gasoline-rationing regulations, arrested a filling station operator and asked to see his rationing coupons. He eventually unlocked a room where the agents discovered the coupons that formed the basis for his conviction. The District Court found that the petitioner had consented to the search — that although he had at first refused to turn the coupons over, he had soon been persuaded to do so and that force or threat of force had not been employed to persuade him. Concluding that it could not be said that this finding was erroneous, this Court, in an opinion by Mr. Justice Douglas that looked to all the circumstances surrounding the consent, affirmed the judgment of conviction: “The public character of the property, the fact that the demand was made during business hours at the place of business where the coupons were required to be kept, the existence of the right to inspect, the nature of the request, the fact that the initial refusal to turn the coupons over was soon followed by acquiescence in the demand — these circumstances all support the conclusion of the District Court.” Id., at 593-594. See also Zap v. United States, 328 U. S. 624.

Conversely, if under all the circumstances it has appeared that the consent was not given voluntarily — that it was coerced by threats or force, or granted only in submission to a claim of lawful authority — then we have found the consent invalid and the search unreasonable. See, e. g., Bumper v. North Carolina, 391 U. S., at 548-549; Johnson v. United States, 333 U. S. 10; Amos v. *234 United States, 255 U. S. 313. In Bumper, a 66-year-old Negro widow, who lived in a house located in a rural area at the end of an isolated mile-long dirt road, allowed four white law enforcement officials to search her home after they asserted they had a warrant to search the house. We held the alleged consent to be invalid, noting that “[w]hen a law enforcement officer claims authority to search a home under a warrant, he announces in effect that the occupant has no right to resist the search. The situation is instinct with coercion — albeit colorably lawful coercion. Where there is coercion there cannot be consent.” 391 U. S., at 550.

Implicit in all of these cases is the recognition that knowledge of a right to refuse is not a prerequisite of a voluntary consent. If the prosecution were required to demonstrate such knowledge, Davis and Zap could not have found consent without evidence of that knowledge. And similarly if the failure to prove such knowledge were sufficient to show an ineffective consent, the Amos, Johnson, and Bumper opinions would surely have focused upon the subjective mental state of the person who consented. Yet they did not.

In short, neither this Court’s prior cases, nor the traditional definition of “voluntariness” requires proof of knowledge of a right to refuse as the sine qua non of an effective consent to a search.15

*235c

It is said, however, that a “consent” is a “waiver” of a person’s rights under the Fourth and Fourteenth Amendments. The argument is that by allowing the police to conduct a search, a person “waives” whatever right he had to prevent the police from searching. It is argued that under the doctrine of Johnson v. Zerbst, 304 U. S. 458, 464, to establish such a “waiver” the State must demonstrate “an intentional relinquishment or abandonment of a known right or privilege.”

But these standards were enunciated in Johnson in the context of the safeguards of a fair criminal trial. Our cases do not reflect an uncritical demand for a knowing and intelligent waiver in every situation where a person has failed to invoke a constitutional protection. As Mr. Justice Black once observed for the Court: “ 'Waiver’ is a vague term used for a great variety of purposes, good and bad, in the law.” Green v. United States, 355 U. S. 184, 191. With respect to procedural due process, for example, the Court has acknowledged that waiver is possible, while explicitly leaving open the question whether a “knowing and intelligent” waiver need be shown.16 See D. H. Overmyer Co. v. Frick Co., *236405 U. S. 174, 185-186; Fuentes v. Shevin, 407 TJ. S. 67, 9A-96.17

The requirement of a “knowing” and “intelligent” waiver was articulated in a case involving the validity of a defendant’s decision to forgo a right constitutionally guaranteed to protect a fair trial and the reliability of the truth-determining process. Johnson v. Zerbst, supra, dealt with the denial of counsel in a federal criminal trial. There the Court held that under the Sixth Amendment a criminal defendant is entitled to the assistance of counsel, and that if he lacks sufficient funds to retain counsel, it is the Government’s obligation to furnish him with a lawyer. As Mr. Justice Black wrote for the Court: “The Sixth Amendment stands as a constant admonition that if the constitutional safeguards it provides be lost, justice will not ‘still be done.’ It embodies a realistic recognition of the obvious truth that the average defendant does not have the professional legal skill to protect himself when brought before a tribunal with power to take his life or liberty, wherein the prosecution is presented by experienced and learned counsel. That which is simple, orderly and necessary to the lawyer, to the untrained layman may appear intricate, complex and mysterious.” 304 TJ. S., at 462-463 (footnote omitted). To preserve the fairness of the trial process the Court established an appropriately heavy burden on the Government before waiver could be found — “an in*237tentional relinquishment or abandonment of a known right or privilege.” Id., at 464.

Almost without exception, the requirement of a knowing and intelligent waiver has been applied only to those rights which the Constitution guarantees to a criminal defendant in order to preserve a fair trial.18 Hence, and hardly surprisingly in view of the facts of Johnson itself, the standard of a knowing and intelligent waiver has most often been applied to test the validity of a waiver of counsel, either at trial,19 or upon a guilty plea.20 And the Court has also applied the Johnson criteria to assess the effectiveness of a waiver of other trial rights such as the right to confrontation,21 to a jury trial,22 and to a speedy trial,23 and the right to be free from *238twice being placed in jeopardy.24 Guilty pleas have been carefully scrutinized to determine whether the accused knew and understood all the rights to which he would be entitled at trial, and that he had intentionally chosen to forgo them.25 And the Court has evaluated the knowing and intelligent nature of the waiver of trial rights in trial-type situations, such as the waiver of the privilege against compulsory self-incrimination before an administrative agency26 or a congressional committee,27 or the waiver of counsel in a juvenile proceeding.28

The guarantees afforded a criminal defendant at trial also protect him at certain stages before the actual trial, and any alleged waiver must meet the strict standard of an intentional relinquishment of a “known” right. But the “trial” guarantees that have been applied to the “pre*239trial” stage of the criminal process are similarly designed to protect the fairness of the trial itself.

Hence, in United States v. Wade, 388 U. S. 218, and Gilbert v. California, 388 U. S. 263, the Court held “that a post-indictment pretrial lineup at which the accused is exhibited to identifying witnesses is a critical stage of the criminal prosecution; that police conduct of such a lineup without notice to and in the absence of his counsel denies the accused his Sixth [and Fourteenth] Amendment right to counsel . . . Id., at 272. Accordingly, the Court indicated that the standard of a knowing and intelligent waiver must be applied to test the waiver of counsel at such a lineup. See United States v. Wade, supra, at 237. The Court stressed the necessary interrelationship between the presence of counsel at a post-indictment lineup before trial and the protection of the trial process itself:

“Insofar as the accused's conviction may rest on a courtroom identification in fact the fruit of a suspect pretrial identification which the accused is helpless to subject to effective scrutiny at trial, the accused is deprived of that right of cross-examination which is an essential safeguard to his right to confront the witnesses against him. Pointer v. Texas, 380 U. S. 400. And even though cross-examination is a precious safeguard to a fair trial, it cannot be viewed as an absolute assurance of accuracy and reliability. Thus in the present context, where so many variables and pitfalls exist, the first line of defense must be the prevention of unfairness and the lessening of the hazards of eyewitness identification at the lineup itself. The trial which might determine the accused’s fate may well not be that in the courtroom but that at the pretrial confrontation, with the State aligned against the accused, the *240witness the sole jury, and the accused unprotected against the overreaching, intentional or unintentional, and with little or no effective appeal from the judgment there rendered by the witness — ‘that's the man.’ ” Id., at 235-236.

And in Miranda v. Arizona, 384 U. S. 436, the Court found that custodial interrogation by the police was inherently coercive, and consequently held that detailed warnings were required to protect the privilege against compulsory self-incrimination. The Court made it clear that the basis for decision was the need to protect the fairness of the trial itself:

“That counsel is present when statements are taken from an individual during interrogation obviously enhances the integrity of the fact-finding processes in court. The presence of an attorney, and the warnings delivered to the individual, enable the defendant under otherwise compelling circumstances to tell his story without fear, effectively, and in a way that eliminates the evils in the interrogation process. Without the protections flowing from adequate warnings and the rights of counsel, ‘all the careful safeguards erected around the giving of testimony, whether by an accused or any other witness, would become empty formalities in a procedure where the most compelling possible evidence of guilt, a confession, would have already been obtained at the unsupervised pleasure of the police.’ ” Id., at 466.

The standards of Johnson were, therefore, found to be a necessary prerequisite to a finding of a valid waiver. See 384 U. S., at 475-479. Cf. Escobedo v. Illinois, 378 U. S., at 490 n. 14.29

*241There is a vast difference between those rights that protect a fair criminal trial and the rights guaranteed under the Fourth Amendment. Nothing, either in the purposes behind requiring a “knowing” and “intelligent” waiver of trial rights, or in the practical application of such a requirement suggests that it ought to be extended to the constitutional guarantee against unreasonable searches and seizures.

A strict standard of waiver has been applied to those rights guaranteed to a criminal defendant to insure that he will be accorded the greatest possible opportunity to utilize every facet of the constitutional model of a fair criminal trial. Any trial conducted in derogation of that model leaves open the possibility that the trial reached an unfair result precisely because all the protections specified in the Constitution were not provided. A prime example is the right to counsel. For without that right, a wholly innocent accused faces the real and substantial danger that simply because of his lack of legal expertise he may be convicted. As Mr. Justice Harlan once wrote: “The sound reason why [the right to counsel] is so freely extended for a criminal trial is the severe injustice risked by confronting an untrained defendant with a range of technical points of law, evidence, and tactics familiar to the prosecutor but not to *242himself.” Miranda v. Arizona, supra, at 514 (dissenting opinion). The Constitution requires that every effort be made to see to it that a defendant in a criminal case has not unknowingly relinquished the basic protections that the Framers thought indispensable to a fair trial.30

The protections of the Fourth Amendment are of a wholly different order, and have nothing whatever to do with promoting the fair ascertainment of truth at a criminal trial. Rather, as Mr. Justice Frankfurter’s opinion for the Court put it in Wolf v. Colorado,, 338 U. S. 25, 27, the Fourth Amendment protects the “security of one’s privacy against arbitrary intrusion by the police . . . .” In declining to apply the exclusionary rule of Mapp v. Ohio, 367 U. S. 643, to convictions that had become final before rendition of that decision, the Court emphasized that “there is no likelihood of unreliability or coercion present in a search-and-seizure case,” Linkletter v. Walker, 381 U. S. 618, 638. In Link-letter, the Court indicated that those cases that had been given retroactive effect went to “the fairness of the trial — the very integrity of the fact-finding process. Here . . . the fairness of the trial is not under attack.” Id., at 639. The Fourth Amendment “is not an adjunct to the ascertainment of truth.” The guarantees of the Fourth Amendment stand “as a protection of quite different constitutional values — values reflecting the concern of our society for the right of each individual to be let alone. To recognize this is no more than to accord those values undiluted respect.” Tehan v. United States ex rel. Shott, 382 U. S. 406, 416.

Nor can it even be said that a search, as opposed to an eventual trial, is somehow “unfair” if a person consents to a search. While the Fourth and Fourteenth *243Amendments limit the circumstances under which the police can conduct a search, there is nothing constitutionally suspect in a person’s voluntarily allowing a search. The actual conduct of the search may be precisely the same as if the police had obtained a warrant. And, unlike those constitutional guarantees that protect a defendant at trial, it cannot be said every reasonable presumption ought to be indulged against voluntary relinquishment. We have only recently stated: “[I]t 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.” Coolidge v. New Hampshire, 403 U. S., at 488. Rather, the community has a real interest in encouraging consent, for the resulting search may yield necessary evidence for the solution and prosecution of crime, evidence that may insure that a wholly innocent person is not wrongly charged with a criminal offense.

Those cases that have dealt with the application of the Johnson v. Zerbst rule make clear that it would be next to impossible to apply to a consent search the standard of “an intentional relinquishment or abandonment of a known right or privilege.” 31 To be true to Johnson *244and its progeny, there must be examination into the knowing and understanding nature of the waiver, an examination that was designed for a trial judge in the structured atmosphere of a courtroom. As the Court expressed it in Johnson:

"The constitutional right of an accused to be represented by counsel invokes, of itself, the protection of a trial court, in which the accused — whose life or liberty is at stake — is without counsel. This protecting duty imposes the serious and weighty responsibility upon the trial judge of determining whether there is an intelligent and competent waiver by the accused. While an accused may waive the right to counsel, whether there is a proper waiver should be clearly determined by the trial court, and it would be fitting and appropriate for that determination to appear upon the record.” 304 U. S., at 465.32

*245It would be unrealistic to expect that in the informal, unstructured context of a consent search, a policeman, upon pain of tainting the evidence obtained, could make the detailed type of examination demanded by Johnson. And, if for this reason a diluted form of “waiver” were found acceptable, that would itself be ample recognition of the fact that there is no universal standard that must be applied in every situation where a person forgoes a constitutional right.33

Similarly, a “waiver” approach to consent searches would be thoroughly inconsistent with our decisions that have approved “third party consents.” In Coolidge v. New Hampshire, 403 U. S., at 487-490, where a wife surrendered to the police guns and clothing belonging to her husband, we found nothing constitutionally impermissible in the admission of that evidence at trial since the wife had not been coerced. Frazier v. Cupp, 394 U. S. 731, 740, held that evidence seized from the defendant's duffel bag in a search authorized by his cousin’s consent was admissible at trial. We found that the defendant had assumed the risk that his cousin, with whom he shared the bag, would allow the police to search it. See also Abel v. United States, 362 U. S. 217. And *246in Hill v. California, 401 U. S. 797, 802-805, we held that the police had validly seized evidence from the petitioner’s apartment incident to the arrest of a third party, since the police had probable cause to arrest the petitioner and reasonably, though mistakenly, believed the man they had arrested was he. Yet it is inconceivable that the Constitution could countenance the waiver of a defendant’s right to counsel by a third party, or that a waiver could be found because a trial judge reasonably, though mistakenly, believed a defendant had waived his right to plead not guilty.34

In short, there is nothing in the purposes or application of the waiver requirements of Johnson v. Zerbst that justifies, much less compels, the easy equation of a knowing waiver with a consent search. To make such an equation is to generalize from the broad rhetoric of some of our decisions, and to ignore the substance of the differing constitutional guarantees. We decline to follow what one judicial scholar has termed “the domino method of constitutional adjudication . . . wherein every explanatory statement in a previous opinion is made the basis for extension to a wholly different situation.” 35

D

Much of what has already been said disposes of the argument that the Court’s decision in the Miranda case requires the conclusion that knowledge of a right to refuse is an indispensable element of a valid consent. The considerations that informed the Court’s holding in Miranda are simply inapplicable in the present case. *247In Miranda the Court found that the techniques of police questioning and the nature of custodial surroundings produce an inherently coercive situation. The Court concluded that “[ujnless adequate protective devices are employed to dispel the compulsion inherent in custodial surroundings, no statement obtained from the defendant can truly be the product of his free choice.” 384 U. S., at 458. And at another point the Court noted that “without proper safeguards the process of in-custody interrogation of persons suspected or accused of crime contains inherently compelling pressures which work to undermine the individual’s will to resist and to compel him to speak where he would not otherwise do so freely.” Id., at 467.

In this case, there is no evidence of any inherently coercive tactics — either from the nature of the police questioning or the environment in which it took place. Indeed, since consent searches will normally occur on a person’s own familiar territory, the specter of incommunicado police interrogation in some remote station house is simply inapposite.36 There is no reason to believe, under circumstances such as are present here, that the response to a policeman’s question is presumptively coerced; and there is, therefore, no reason to reject the traditional test for determining the voluntariness of a person’s response. Miranda, of course, did not reach investigative questioning of a person not in custody, which is most directly analogous to the situation of a consent search, and it assuredly did not indicate that such questioning ought to be deemed inherently coercive. See su-pra, at 232.

It is also argued that the failure to require the Government to establish knowledge as a prerequisite to a valid *248consent, will relegate the Fourth Amendment to the special province of “the sophisticated, the knowledgeable and the privileged.” We cannot agree. The traditional definition of voluntariness we accept today has always taken into account evidence of minimal schooling, low intelligence, and the lack of any effective warnings to a person of his,rights; and the voluntariness of any statement taken under those conditions has been carefully scrutinized to determine whether it was in fact voluntarily given.37

E

Our decision today is a narrow one. We hold only that when the subject of a search is not in custody and the State attempts to justify a search on the basis of his consent, the Fourth and Fourteenth Amendments require that it demonstrate that the consent was in fact voluntarily given, and not the result of duress or coercion, express or implied. Voluntariness is a question of fact *249to be determined from all the circumstances, and while the subject’s knowledge of a right to refuse is a factor to be taken into account, the prosecution is not required to demonstrate such knowledge as a prerequisite to establishing a voluntary consent.38 Because the California court followed these principles in affirming the respondent’s conviction, and because the Court of Appeals for the Ninth Circuit in remanding for an evidentiary hearing required more, its judgment must be reversed.

It is so ordered.

Mr. Justice Blackmun,

concurring.

I join the Court’s opinion and its judgment.

At the time Kaufman v. United States, 394 U. S. 217 (1969), was decided, I, as a member of the Court of Appeals (but not of its panel) whose order was there reversed, found myself in agreement with the views expressed by Mr. Justice Harlan, writing for himself and my Brother Stewart in dissent. Id., at 242. My attitude has not changed in the four years that have passed since Kaufman was decided.

Although I agree with nearly all that Mr. Justice Powell has to say in his detailed and persuasive concurring opinion, post, p. 250, I refrain from joining it at this time because, as Mr. Justice Stewart’s opinion reveals, it is not necessary to reconsider Kaufman in order to decide the present case.

*250Mr. Justice Powell,

with whom The Chief Justice and Mr. Justice Rehnquist join, concurring.

While I join the opinion of the Court, it does not address what seems to me the overriding issue briefed and argued in this case: the extent to which federal habeas corpus should be available to a state prisoner seeking to exclude evidence from an allegedly unlawful search and seizure. I would hold that federal collateral review of a state prisoner’s Fourth Amendment claims — claims which rarely bear on innocence — should be confined solely to the question of,whether the petitioner was provided a fair opportunity to raise and have adjudicated the question in state courts. In view of the importance of this issue to our system of criminal justice, I think it appropriate to express my views.

I

Although petitions for federal habeas corpus assert a wide variety of constitutional questions, we are concerned in this case only with a Fourth Amendment claim that an unlawful search occurred and that the state court erred in failing to exclude the evidence obtained therefrom. A divided court in Kaufman v. United States, 394 U. S. 217 (1969), held that collateral review of search-and-seizure claims was appropriate on motions filed by federal prisoners under 28 U. S. C. § 2255. Until Kaufman, a substantial majority of the federal courts of appeals had considered that claims of unlawful search and seizure “ 'are not proper matters to be presented by a motion to vacate sentence under § 2255 ....’” Id., at 220. The rationale of this view was fairly summarized by the Court:

“The denial of Fourth Amendment protection against unreasonable searches and seizures, the Gov*251ernment’s argument runs, is of a different nature from denials of other constitutional rights which we have held subject to collateral attack by federal prisoners. For unlike a claim of denial of effective counsel or of violation of the privilege against self incrimination, as examples, a claim of illegal search and seizure does not impugn the integrity of the fact-finding process or challenge evidence as inherently unreliable; rather, the exclusion of illegally seized evidence is simply a prophylactic device intended generally to deter Fourth Amendment violations by law enforcement officers.” Id., at 224.

In rejecting this rationale, the Court noted that under prior decisions “the federal habeas remedy extends to state prisoners alleging that unconstitutionally obtained evidence was admitted against them at trial,”1 and concluded that there was no basis for restricting “access by federal prisoners with illegal search-and-seizure claims to federal collateral remedies, while placing no similar restriction on access by state prisoners.” Id., at 225-226. In short, on petition for habeas corpus or collateral review filed in a federal district court, whether by state prisoners under 28 U. S. C. § 2254 or federal prisoners under § 2255, the present rule is that Fourth Amendment claims may be asserted and the exclusionary rule must be applied in precisely the same manner as on direct review. Neither the history or purpose of habeas corpus, the desired prophylactic utility of the exclusionary rule as applied to Fourth Amendment claims, nor any sound reason relevant to the administration of criminal justice in our federal system justifies such a power.

*252II

The federal review involved in this Fourth Amendment case goes well beyond the traditional purpose of the writ of habeas corpus. Much of the present perception of habeas corpus stems from a revisionist view of the historic function that writ was meant to perform. The critical historical argument has focused on the nature of the writ at the time of its incorporation in our Constitution and at the time of the Habeas Corpus Act of 1867, the direct ancestor of contemporary habeas corpus statutes.2 In Fay v. Nota, 372 U. S. 391, 426 (1963), the Court interpreted the writ’s historic position as follows:

"At the time the privilege of the writ was written into the Federal Constitution it was settled that the writ lay to test any restraint contrary to fundamental law, which in England stemmed ultimately from Magna Charta but in this country was embodied in the written Constitution. Congress in 1867 sought to provide a federal forum for state prisoners having constitutional defenses by extending the habeas corpus powers of the federal courts to their constitutional maximum. Obedient to this purpose, we have consistently held that federal court *253jurisdiction is conferred by the allegation of an unconstitutional restraint and is not defeated by anything that may occur in the state court proceedings.”

If this were a correct interpretation of the relevant history, the present wide scope accorded the writ would have arguable support, despite the impressive reasons to the contrary. But recent scholarship has cast grave doubt on Fay’s version of the writ’s historic function.

It has been established that both the Framers of the Constitution and the authors of the 1867 Act expected that the scope of habeas corpus would be determined with reference to the writ’s historic, common-law development.3 Mr. Chief Justice Marshall early referred to the common-law conception of the writ in determining its constitutional and statutory scope, Ex parte Bollman, 4 Cranch 75, 93-94 (1807); Ex parte Watkins, 3 Pet. 193, 201-202 (1830), and Professor Oaks has noted that “when the 1867 Congress provided that persons restrained of their liberty in violation of the Constitution could obtain a writ of habeas corpus from a federal court, it undoubtedly intended — except to the extent the legislation provided otherwise — to incorporate the common-law uses and functions of this remedy.” 4

It thus becomes important to understand exactly what was the common-law scope of the writ both when embraced by our Constitution and incorporated into the Habeas Corpus Act of 1867. Two respected scholars have recently explored precisely these questions.5 Their efforts *254have been both meticulous and revealing. Their conclusions differ significantly from those of the Court in Fay v. Noia, that habeas corpus traditionally has been available “to remedy any kind of governmental restraint contrary to fundamental law.” 372 U. S., at 405.

The considerable evidence marshaled by these scholars need not be restated here. Professor Oaks makes a convincing case that under the common law of habeas corpus at the time of the adoption of the Constitution, “once a person had been convicted by a superior court of general jurisdiction, a court disposing of a habeas corpus petition could not go behind the conviction for any purpose other than to verify the formal jurisdiction of the committing court.” 6 Certainly that was what Mr. Chief Justice Marshall understood when he stated:

“This writ {habeas corpus] is, as has been said, in the nature of a writ of error which brings up the body of the prisoner with the cause of commitment. The court can undoubtedly inquire into the sufficiency of that cause; but if it be the judgment of a court of competent jurisdiction, especially a judgment withdrawn by law from the revision of this court, is not that judgment in itself sufficient cause? Can the court, upon this writ, look beyond the judgment, and re-examine the charges on which it was rendered. A judgment, in its nature, concludes the subject on which it is rendered, and pronounces the law of the case. The judgment of a court of record whose jurisdiction is final, is as conclusive on all the world as the judgment of this court would be. It is as conclusive on this court as it is on other courts. It puts an end to inquiry concerning the fact, by deciding it.” Ex parte Watkins, 3 Pet., at 202-203.

*255The respect shown under common law for the finality of the judgment of a committing court at the time of the Constitution and in the early 19th century did not, of course, explicitly contemplate the operation of habeas corpus in the context of federal-state relations. Federal habeas review for state prisoners was not available until passage of the Habeas Corpus Act of 1867. Yet there is no evidence that Congress intended that Act to jettison the respect theretofore shown by a reviewing court for prior judgments by a court of proper jurisdiction. The Act “received only the most perfunctory attention and consideration in the Congress; indeed, there were complaints that its effects could not be understood at all.” 7 In fact, as Professor Bator notes, it would require overwhelming evidence, which simply is not present, to conclude that the 1867 Congress intended “to tear habeas corpus entirely out of the context of its historical meaning and scope and convert it into an ordinary writ of error with respect to all federal questions in all criminal cases.” 8 Rather, the House Judiciary Committee when it reviewed the Act in 1884 understood that it was not “contemplated by its framers or . . . properly . . . construed to authorize the overthrow of the final judgments of the State courts of general jurisdiction, by the inferior Federal judges. ...”9

Much, of course, has transpired since that first Habeas Corpus Act. See Fay v. Noia, 372 U. S., at 449-463 (Harlan, J., dissenting). The scope of federal habeas corpus for state prisoners has evolved from a quite limited inquiry into whether the committing state court had jurisdiction, Andrews v. Swartz, 156 U. S. 272 (1895); In re *256 Moran, 203 U. S. 96 (1906), to whether the applicant had been given an adequate opportunity in state court to raise his constitutional claims, Frank v. Mangum, 237 U. S. 309 (1915); and finally to actual redetermination in federal court of state court rulings on a wide variety of constitutional contentions, Brown v. Allen, 344 U. S. 443 (1953). No one would now suggest that this Court be imprisoned by every particular of habeas corpus as it existed in the late 18th and 19th centuries. But recognition of that reality does not liberate us from all historical restraint. The historical evidence demonstrates that the purposes of the writ, at the time of the adoption of the Constitution, were tempered by a due regard for the finality of the judgment of the committing court. This regard was maintained substantially intact when Congress, in the Habeas Corpus Act of 1867, first extended federal habeas review to the delicate interrelations of our dual court systems.

Ill

Recent decisions, however, have tended to depreciate the importance of the finality of prior judgments in criminal cases. Kaufman, 394 U. S., at 228; Sanders v. United States, 373 U. S. 1, 8 (1963); Fay, supra, at 424. This trend may be a justifiable evolution of the use of habeas corpus where the one in state custody raises a constitutional claim bearing on his innocence. But the justification for disregarding the historic scope and function of the writ is measurably less apparent in the typical Fourth Amendment claim asserted on collateral attack. In this latter case, a convicted defendant is most often asking society to redetermine a matter with no bearing at all on the basic justice of his incarceration.

Habeas corpus indeed should provide the added assurance for a free society that no innocent man suffers an unconstitutional loss of liberty. The Court in Fay described *257habeas corpus as a remedy for “whatever society deems to be intolerable restraints,” and recognized that those to whom the writ should be granted “are persons whom society has grievously wronged and for whom belated liberation is little enough compensation.” Id., at 401-402, 441. The Court there acknowledged that the central reason for the writ lay in remedying injustice to the individual. Recent commentators have recognized the same core concept, one noting that “where person-al liberty is involved, a democratic society . . . insists that it is less important to reach an unshakable decision than to do justice (emphasis added),”10 and another extolling the use of the writ in Leyra v. Denno, 347 U. S. 556 (1954), with the assertion that “[b]ut for federal habeas corpus, these two men would have gone to their deaths for crimes of which they were found not guilty.” 11

I am aware that history reveals no exact tie of the writ of habeas corpus to a constitutional claim relating to innocence or guilt. Traditionally, the writ was unavailable even for many constitutional pleas grounded on a claimant’s innocence, while many contemporary proponents of expanded employment of the writ would permit its issuance for one whose deserved confinement was never in doubt. We are now faced, however, with the task of accommodating the historic respect for the finality of the judgment of a committing court with recent Court expansions of the role of the writ. This accommodation can best be achieved, with due regard to all of the values implicated, by recourse to the central reason for habeas corpus: the affording of means, *258through an extraordinary writ, of redressing an unjust incarceration.

Federal habeas review of search and seizure claims is rarely relevant to this reason. Prisoners raising Fourth Amendment claims collaterally usually are quite justly detained. The evidence obtained from searches and seizures is often “the clearest proof of guilt” with a very high content of reliability.12 Rarely is there any contention that the search rendered the evidence unreliable or that its means cast doubt upon the prisoner’s guilt. The words of Mr. Justice Black drive home the point:

“A claim of illegal search and seizure under the Fourth Amendment is crucially different from many other constitutional rights; ordinarily the evidence seized can in no way have been rendered untrustworthy by the means of its seizure and indeed often this evidence alone establishes beyond virtually any shadow of a doubt that the defendant is guilty.” Kaufman v. United States, 394 U. S., at 237 (1969) (dissenting opinion).

Habeas corpus review of search and seizure claims thus brings a deficiency of our system of criminal justice into sharp focus: a convicted defendant asserting no constitutional claim bearing on innocence and relying solely on an alleged unlawful search, is now entitled to federal habeas review of state conviction and the likelihood of release if the reviewing court concludes that the search was unlawful. That federal courts would actually redetermine constitutional claims bearing no relation to the prisoner’s innocence with the possibility of releasing him from custody if the search is held unlawful not only defeats our societal interest in a rational legal system but serves no compensating ends of personal justice.

*259IV

This unprecedented extension of habeas corpus far beyond its historic bounds and in disregard of the writ’s central purpose is an anomaly in our system sought to be justified only by extrinsic reasons which will be addressed in Part Y of this opinion. But first let us look at the costs of this anomaly — costs in terms of serious intrusions on other societal values. It is these other values that have been subordinated — not to further justice on behalf of arguably innocent persons but all too often to serve mechanistic rules quite unrelated to justice in a particular case. Nor are these neglected values unimportant to justice in the broadest sense or to our system of Government. They include (i) the most effective utilization of limited judicial resources, (ii) the necessity of finality in criminal trials, (iii) the minimization of friction between our federal and state systems of justice, and (iv) the maintenance of the constitutional balance upon which the doctrine of federalism is founded.

When raised on federal habeas, a claim generally has been considered by two or more tiers of state courts. It is the solemn duty of these courts, no less than federal ones, to safeguard personal liberties and consider federal claims in accord with federal law. The task which federal courts are asked to perform on habeas is thus most often one that has or should have been done before. The presumption that “if a job can be well done once, it should not be done twice” is sound and one calculated to utilize best “the intellectual, moral, and political resources involved in the legal system.” 13

*260Those resources are limited but demand on them constantly increases. There is an insistent call on federal courts both in civil actions, many novel and complex, which affect intimately the lives of great numbers of people and in original criminal trials and appeals which deserve our most careful attention.14 To the extent the federal courts are required to re-examine claims on collat*261eral attack,15 they deprive primary litigants of their prompt availability and mature reflection. After all, the resources of our system are finite: their overextension jeopardizes the care and quality essential to fair adjudication.

The present scope of federal habeas corpus also has worked to defeat the interest of society in a rational point of termination for criminal litigation. Professor Amsterdam has identified some of the finality interests at stake in collateral proceedings:

“They involve (a) duplication of judicial effort; (b) delay in setting the criminal proceeding at rest; (c) inconvenience and possibly danger in transporting a prisoner to the sentencing court for hearing; (d) postponed litigation of fact, hence litigation which will often be less reliable in reproducing the facts (i) respecting the postconviction claim itself, and (ii) respecting the issue of guilt if the collateral attack succeeds in a form which allows retrial. . . .”

He concluded that:

“[I]n combination, these finality considerations amount to a more or less persuasive argument against the cognizability of any particular collateral *262claim, the strength of the argument depending upon the nature of the claim, the manner' of its treatment (if any) in the conviction proceedings, and the circumstances under which collateral litigation must be had.” 16

No effective judicial system can afford to concede the continuing theoretical possibility that there is error in every trial and that every incarceration is unfounded. At some point the law must convey to those in custody that a wrong has been committed, that consequent punishment has been imposed, that one should no longer look back with the view to resurrecting every imaginable basis for further litigation but rather should look forward to rehabilitation and to becoming a constructive citizen.17

Nowhere should the merit of this view be more self-evident than in collateral attack on an allegedly unlawful search and seizure, where the petitioner often asks society to redetermine a claim with no relationship at all to the justness of his confinement. Professor Amsterdam has noted that “for reasons which are common to all search and seizure claims,” he “would hold even a slight finality interest sufficient to deny the collateral remedy.” 18 But, in fact, a strong finality interest militates against allow*263ing collateral review of search-and-seizure claims. Apart from the duplication of resources inherent in most habeas corpus proceedings, the validity of a search-and-seizure claim frequently hinges on a complex matrix of events which may be difficult indeed for the habeas court to disinter especially where, as often happens, the trial occurred years before the collateral attack and the state record is thinly sketched.19

Finally, the present scope of habeas corpus tends to undermine the values inherent in our federal system of government. To the extent that every state criminal judgment is to be subject indefinitely to broad and repetitive federal oversight, we render the actions of state courts a serious disrespect in derogation of the constitutional balance between the two systems.20 The present expansive scope of federal habeas review has prompted no small friction between state and federal judiciaries. Justice Paul C. Reardon of the Massachusetts Supreme *264Judicial Court and then President of the National Center for State Courts, in identifying problems between the two systems, noted bluntly that “[t]he first, without question, is the effect of Federal habeas corpus proceedings on State courts.” He spoke of the “humiliation of review from the full bench of the highest State appellate court to a single United States District Court judge.” Such broad federal habeas powers encourage in his view the “growing denigration of the State courts and their functions in the public mind.” 21 In so speaking Justice Reardon echoed the words of Professor Bator:

“I could imagine nothing more subversive of a judge’s sense of responsibility, of the inner subjective conscientiousness which is so essential a part of the difficult and subtle art of judging well, than an in*265discriminate acceptance of the notion that all the shots will always be called by someone else.” 22

In my view, this Court has few more pressing responsibilities than to restore the mutual respect and the balanced .sharing of responsibility between the state and federal courts which our tradition and the Constitution itself so wisely contemplate. This can be accomplished without retreat from our inherited insistence that the writ of habeas corpus retain its full vitality as a means of redressing injustice.

This case involves only a relatively narrow aspect of the appropriate reach of habeas corpus. The specific issue before us, and the only one that need be decided at this time, is the extent to which a state prisoner may obtain federal habeas corpus review of a Fourth Amendment claim. Whatever may be formulated as a more comprehensive answer to the important broader issues (whether by clarifying legislation or in subsequent decisions), Mr. Justice Black has suggested what seems to me to be the appropriate threshold requirement in a case of this kind:

“I would always require that the convicted defendant raise the kind of constitutional claim that casts some shadow of a doubt on his guilt.” Kaufman v. United States, 394 U. S., at 242 (dissenting opinion).

In a perceptive analysis, Judge Henry J. Friendly expressed a similar view. He would draw the line against habeas corpus review in the absence of a “colorable claim of innocence”:

“[W]ith a few important exceptions, convictions should be subject to collateral attack only when *266the prisoner supplements his constitutional plea with a colorable claim of innocence.” 23

Where there is no constitutional claim bearing on innocence, the inquiry of the federal court on habeas review of a state prisoner’s Fourth Amendment claim should be confined solely to the question whether the defendant was provided a fair opportunity in the state courts to raise and have adjudicated the Fourth Amendment claim. Limiting the scope of habeas review in this manner would reduce the role of the federal courts in determining the merits of constitutional claims with no relation to a petitioner’s innocence and contribute to the restoration of recently neglected values to their proper place in our criminal justice system.

Y

The importance of the values referred to above is not questioned. What, then, is the reason which has prompted this Court in recent decisions to extend habeas corpus to Fourth Amendment claims largely in disregard of its history as well as these values? In addressing Mr. Justice Black’s dissenting view that constitutional claims raised collaterally should be relevant to the petitioner’s innocence, the majority in Kaufman noted:

“It [Mr. Justice Black’s view] brings into question the propriety of the exclusionary rule itself. The application of that rule is not made to turn on the *267existence of a possibility of innocence; rather, exclusion of illegally obtained evidence is deemed necessary to protect the right of all citizens, not merely the citizen on trial, to be secure against unreasonable searches and seizures.” 394 U. S., at 229. (Emphasis added.)

The exclusionary rule has occasioned much criticism, largely on grounds that its application permits guilty defendants to go free and law-breaking officers to go unpunished.24 The oft-asserted reason for the rule is to deter illegal searches and seizures by the police, Elkins v. United States, 364 U. S. 206, 217 (1960); Mapp v. Ohio, 367 TJ. S. 643, 656 (1961) ; Linkletter v. Walker, 381 U. S. 618, 636 (1965); Terry v. Ohio, 392 U. S. 1, 29 (1968).25 *268The efficacy of this deterrent function, however, has been brought into serious question by recent empirical research. Whatever the rule’s merits on an initial trial and appeal26 — a question not in issue here — the case for *269collateral application of the rule is an anemic one. On collateral attack, the exclusionary rule retains its major liabilities while the asserted benefit of the rule dissolves. For whatever deterrent function the rule may serve when applied on trial and appeal becomes greatly attenuated when, months or years afterward, the claim surfaces for collateral review. The impermissible conduct has long since occurred, and the belated wrist slap of state police by federal courts harms no one but society on whom the convicted criminal is newly released.27

Searches and seizures are an opaque area of the law: flagrant Fourth Amendment abuses will rarely escape detection but there is a vast twilight zone with respect to which one Justice has stated that our own “decisions . . . are hardly notable for their predictability,” 28 and another has observed that this Court was “ 'bifurcating elements too infinitesimal to be split.’ ” 29 Serious Fourth Amendment infractions can be dealt with by state judges or by this Court on direct review. But the nonfrivolous Fourth Amendment claims that survive for collateral attack are most likely to be in this grey, twilight area, where the law is difficult for courts to apply, let alone for the policeman on the beat to understand. This is. *270precisely the type of case where the deterrent function of the exclusionary rule is least efficacious, and where there is the least justification for freeing a duly convicted defendant.30

Our decisions have not encouraged the thought that what may be an appropriate constitutional policy in one context automatically becomes such for all times and all seasons. In Linkletter v. Walker, 381 U. S., at 629, the Court recognized the compelling practical considerations against retroactive application of the exclusionary rule. Rather than viewing the rule as having eternal constitutional verity, the Court decided to

“weigh the merits and demerits in each case by looking to the prior history of the rule in question, its purpose and effect, and whether retrospective operation will further or retard its operation. We believe that this approach is particularly correct with reference to the Fourth Amendment’s prohibitions as to unreasonable searches and seizures.” Id., at 629.

Such a pragmatic approach compelled the Court to conclude that the rule’s deterrent function would not be advanced by its retrospective application:

“The misconduct of the police prior to Mapp has already occurred and will not be corrected by releasing the prisoners involved. . . . Finally, the ruptured privacy of the victims’ homes and effects cannot be restored. Reparation comes too late.” Id., at 637.

See also Desist v. United States, 394 U. S. 244 (1969).

The same practical, particularized analysis of the exclusionary rule’s necessity also was evident in Walder v. United States, 347 U. S. 62 (1954), when the Court per*271mitted the Government to utilize unlawfully seized evidence to impeach the credibility of a defendant who had first testified broadly in his own defense. The Court held, in effect, that the policies protected by the exclusionary rule were outweighed in this case by the need to prevent perjury and assure the integrity of proceedings at trial. The Court concluded that to apply the exclusionary rule in such circumstances “would be a perversion of the Fourth Amendment.” Id., at 65. The judgment in Walder revealed most pointedly that the policies behind the exclusionary rule are neither absolute nor all-encompassing, but rather must be weighed and balanced against a competing and more compelling policy, namely the need for effective determination of truth at trial.

In sum: the case for the exclusionary rule varies with the setting in which it is imposed. It makes little sense to extend the Mapp exclusionary rule to a federal habeas proceeding where its asserted deterrent effect must be least efficacious, and its obvious harmful consequences persist in full force.

VI

The final inquiry is whether the above position conforms to 28 U. S. C. § 2254 (a) which provides:

“The Supreme Court, a Justice thereof, a circuit judge, or a district court shall entertain an application for a writ of habeas corpus in behalf of a person in custody pursuant to the judgment of a State court only on the ground that he is in custody in violation of the Constitution or laws or treaties of the United States.”

The trend in recent years has witnessed a proliferation of constitutional rights, “a vast expansion of the claims of error in criminal cases for which a resourceful defense lawyer can find a constitutional basis.” 31 Federal ha-*272beas jurisdiction has been extended far beyond anyone’s expectation or intendment when the concept of “custody in violation of the Constitution,” now in § 2254 (a), first appeared in federal law over a century ago.32

Mr. Justice Black was clearly correct in noting that “not every conviction based in part on a denial of a constitutional right is subject to attack by habeas corpus or § 2255 proceedings after a conviction has become final.” Kaufman, 394 U. S., at 232 (dissenting opinion). No evidence exists that Congress intended every allegation of a constitutional violation to afford an appropriate basis for collateral review: indeed, the latest revisions of the Federal Habeas Corpus statute in 1966 33 and the enactment of § 2254 (a) came at the time a majority of the courts of appeals held that claims of unlawful search and seizure “ ‘are not proper matters to be presented by a motion to vacate sentence under § 2255 but can only be properly presented by appeal from the conviction.’ ” Id., at 220, quoting Warren v. United States, 311 F. 2d 673, 675 (CA8 1963).34 Though the precise discussion in Kaufman concerned the claims of federal prisoners under § 2255, the then-existing principle of a distinction between review of search-and-seizure claims in direct and collateral proceedings clearly existed.

There is no indication that Congress intended to wipe out this distinction. Indeed, the broad purpose of the 1966 amendments pointed in the opposite direction. The report of the Senate Judiciary Committee notes that:

“Although only a small number of these [habeas] applications have been found meritorious, the ap*273plications in their totality have imposed a heavy burden on the Federal courts. . . . The bill seeks to alleviate the unnecessary burden by introducing a greater degree of finality of judgments in habeas corpus proceedings.” S. Rep. No. 1797, 89th Cong., 2d Sess., 2 (1966).35

The House Report states similarly that:

“While in only a small number of these applications have the petitioners been successful, they nevertheless have not only imposed an unnecessary burden on the work of the Federal courts but have also greatly interfered with the procedures and processes of the State courts by delaying, in many cases, the proper enforcement of their judgments.” H. R. Rep. No. 1892, 89th Cong., 2d Sess., 5 (1966).

This most recent congressional expression on the scope of federal habeas corpus reflected the sentiment, shared alike by judges and legislators, that the writ has overrun its historical banks to inundate the dockets of federal courts and denigrate the role of state courts. Though Congress did not address the precise question at hand, nothing in §2254 (a), the state of the law at the time of its adoption, or the historical uses of the language “custody in violation of the Constitution” from which § 2254 (a) is derived,36 compels a holding that rulings of state courts on claims of unlawful search and *274seizure must be reviewed and redetermined in collateral proceedings.

YII

Perhaps no single development of the criminal law has had consequences so profound as the escalating use, over the past two decades, of federal habeas corpus to reopen and readjudicate state criminal judgments. I have commented in Part IV above on the far-reaching consequences: the burden on the system,37 in terms of demands on the courts, prosecutors, defense attorneys, and other personnel and facilities; the absence of efficiency and finality in the criminal process, frustrating both the deterrent function of the law and the effectiveness of rehabilitation ; the undue subordination of state courts, with the resulting exacerbation of state-federal relations; and the subtle erosion of the doctrine of federalism itself. Perhaps the single most disquieting consequence of open-ended habeas review is reflected in the prescience of Mr. Justice Jackson’s warning that “[i]t must prejudice the occasional meritorious application to be buried in a flood of worthless ones.” 38

If these consequences flowed from the safeguarding of constitutional claims of innocence they should, of course, be accepted as a tolerable price to pay for cherished standards of justice at the same time that efforts are pursued to find more rational procedures. Yet, as illustrated by the case before us today, the question on habeas corpus is *275too rarely whether the prisoner was innocent of the crime for which he was convicted39 and too frequently whether some evidence of undoubted probative value has been admitted in violation of an exclusionary rule ritualistically applied without due regard to whether it has the slightest likelihood of achieving its avowed prophylactic purpose.

It is this paradox of a system, which so often seems to subordinate substance to form, that increasingly provokes criticism and lack of confidence. Indeed, it is difficult to explain why a system of criminal justice deserves respect which allows repetitive reviews of convictions long since held to have been final at the end of the normal process of trial and appeal where the basis for re-examination is not even that the convicted defendant was innocent. There has been a halo about the “Great Writ” that no one would wish to dim. Yet one must wonder whether the stretching of its use far beyond any justifiable purpose will not in the end weaken rather than strengthen the writ’s vitality.

Me. Justice Douglas,

dissenting.

I agree with the Court of Appeals that “verbal assent” to a search is not enough, that the fact that consent was given to the search does not imply that the suspect knew that the alternative of a refusal existed. 448 F. 2d 699, 700. As that court stated:

“[U]nder many circumstances a reasonable person might read an officer's ‘May I’ as the courteous ex*276pression of a demand backed, by force of law.” Id., at 701.

A considerable constitutional guarantee rides on this narrow issue. At the time of the search there was no probable cause to believe that the car contained contraband or other unlawful articles. The car was stopped only because a headlight and the license plate light were burned out. The car belonged to Alcala’s brother, from whom it was borrowed, and Alcala had a driver’s license. Traffic citations were appropriately issued. The car was searched, the present record showing that Alcala consented. But whether Alcala knew he had the right to refuse, we do not know. All the Court of Appeals did was to remand the case to the District Court for a finding — and if necessary, a hearing on that issue.

I would let the case go forward on that basis. The long, time-consuming contest in this Court might well wash out. At least we could be assured that, if it came back, we would not be rendering an advisory opinion. Had I voted to grant this petition, I would suggest we dismiss it as improvidently granted. But, being in the minority, I am bound by the Rule of Four.

Mr. Justice Brennan,

dissenting.

The Fourth Amendment specifically guarantees “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures . . . .” We have consistently held that governmental searches conducted pursuant to a validly obtained warrant or reasonably incident to a valid arrest do not violate this guarantee. Here, however, as the Court itself recognizes, no search warrant was obtained and the State does not even suggest “that there was probable cause to search the vehicle or that the search was incident to a valid arrest of any of the occupants.” Ante, *277at 227-228. As a result, the search of the vehicle can be justified solely on the ground that the owner’s brother gave his consent — that is, that he waived his Fourth Amendment right “to be secure” against an otherwise “unreasonable” search. The Court holds today that an individual can effectively waive this right even though he is totally ignorant of the fact that, in the absence of his consent, such invasions of his privacy would be constitutionally prohibited. It wholly escapes me how our citizens can meaningfully be said to have waived something as precious as.a constitutional guarantee without ever being aware of its existence. In my view, the Court’s conclusion is supported neither by “linguistics,” nor by “epistemology,” nor, indeed, by “common sense.” I respectfully dissent.

Mr. Justice Marshall,

dissenting.

Several years ago, Mr. Justice Stewart reminded us that “[t]he Constitution guarantees ... a society of free choice. Such a society presupposes the capacity of its members to choose.” Ginsberg v. New York, 390 U. S. 629, 649 (1968) (concurring in result). I would have thought that the capacity to choose necessarily depends upon knowledge that there is a choice to be made. But today the Court reaches the curious result that one can choose to relinquish a constitutional right— the right to be free of unreasonable searches — without knowing that he has the alternative of refusing to accede to a police request to search.1 I cannot agree, and therefore dissent.

*278I

1 believe that the Court misstates the true issue in this case. That issue is not, as the Court suggests, whether the police overbore Alcala’s will in eliciting his consent, but rather, whether a simple statement of assent to search, without more,2 should be sufficient to permit the police to search and thus act as a relinquishment of Alcala’s constitutional right to exclude the police.3 This Court has always scrutinized with great care claims that a person has forgone the opportunity to assert constitutional rights. See, e. g., Fuentes v. Shevin, 407 U. S. 67 (1972); D. H. Overmyer Co. v. Frick Co., 405 U. S. 174 (1972); Boykin v. Alabama, 395 U. S. 238 (1969); Carnley v. Cochran, 369 U. S. 506 (1962). I see no reason to give the claim that a person consented to a search any less rigorous scrutiny. Every case in this Court involving this kind of search has heretofore spoken *279of consent as a waiver.4 See, e. g., Amos v. United States, 255 TJ. S. 313, 317 (1921); Zap v. United States, 328 U. S. 624, 628 (1946); Johnson v. United States, 333 U. S. 10, 13 (1948).5 Perhaps one skilled in lin*280guistics or epistemology can disregard those comments, but I find them hard to ignore.

To begin, it is important to understand that the opinion of the Court is misleading in its treatment of the issue here in three ways. First, it derives its criterion for determining when a verbal statement of assent to search operates as a relinquishment of a person’s right to preclude entry from a justification of consent searches that is inconsistent with our treatment in earlier cases of exceptions to the requirements of the Fourth Amendment, and that is not responsive to the unique nature of the consent-search exception. Second, it applies a standard of voluntariness that was developed in a very different context, where the standard was based on policies different from those involved in this case. Third, it mischaracterizes our prior cases involving consent searches.

A

The Court assumes that the issue in this case is: what are the standards by which courts are to determine that consent is voluntarily given? It then imports into the law of search and seizure standards developed to decide entirely different questions about coerced confessions.6

The Fifth Amendment, in terms, provides that no person “shall be compelled in any criminal case to be a witness against himself.” Nor is the interest protected by the Due Process Clause of the Fourteenth Amendment any different. The inquiry in a case where a confession is challenged as having been elicited in an unconstitutional manner is, therefore, whether the behavior *281of the police amounted to compulsion of the defendant.7 Because of the nature of the right to be free of compulsion, it would be pointless to ask whether a defendant knew of it before he made a statement; no sane person would knowingly relinquish a right to be free of compulsion. Thus, the questions of compulsion and of violation of the right itself are inextricably intertwined. The cases involving coerced confessions, therefore, pass over the question of knowledge of that right as irrelevant, and turn directly to the question of compulsion.

Miranda v. Arizona, 384 U. S. 436 (1966), confirms this analysis. There the Court held that certain warnings must be given to suspects prior to their interrogation so that the inherently coercive nature of in-custody questioning would be diminished by the suspect’s knowledge that he could remain silent. But, although those warnings, of course, convey information about various rights of the accused, the information is intended only to protect the suspect against acceding to the other coercive aspects of police interrogation. While we would not ordinarily think that a suspect could waive his right to be free of coercion, for example, we do permit suspects to waive the rights they are informed of by police warnings, on the belief that such information in itself sufficiently decreases the chance that a statement would be elicited by compulsion. Id., at 475-476. Thus, nothing the defendant did in the cases involving coerced confessions was taken to operate as a relinquishment of his rights; certainly the fact that the defendant made *282a statement was never taken to be a relinquishment of the right to be free of coercion.8

B

In contrast, this case deals not with “coercion,” but with “consent,” a subtly different concept to which different standards have been applied in the past. Freedom from coercion is a substantive right, guaranteed by the Fifth and Fourteenth Amendments. Consent, however, is a mechanism by which substantive requirements, otherwise applicable, are avoided. In the context of the Fourth Amendment, the relevant substantive requirements are that searches be conducted only after evidence justifying them has been submitted to an impartial magistrate for a determination of probable cause. There are, of course, exceptions to these requirements based on a variety of exigent circumstances that make it impractical to invalidate a search simply because the police failed to get a warrant.9 But none of the exceptions *283relating to the overriding needs of law enforcement are applicable when a search is justified solely by consent. On the contrary, the needs of law enforcement are significantly more attenuated, for probable cause to search may be lacking but a search permitted if the subject’s consent has been obtained. Thus, consent searches are permitted, not because such an exception to the requirements of probable cause and warrant is essential to proper law enforcement, but because we permit our citizens to choose whether or not they wish to exercise their constitutional rights. Our prior decisions simply do not support the view that a meaningful choice has been made solely because no coercion was brought to bear on the subject.

For example, in Bumper v. North Carolina, 391 U. S. 543 (1968), four law enforcement officers went to the home of Bumper’s grandmother. They announced that they had a search warrant, and she permitted them to enter. Subsequently, the prosecutor chose not to rely on the warrant, but attempted to justify the search by the woman’s consent. We held that consent could not be established “by showing no more than acquiescence to a claim of lawful authority,” id., at 548-549. We did not there inquire into all the circumstances, but focused on a single fact, the claim of authority, even though the grandmother testified that no threats were made. Id., at 547 n. 8. It may be that, on the facts of that case, her consent was under all the circumstances involuntary, but it is plain that we did not apply the test adopted by the Court today. And, whatever the posture of the case when it reached this Court, it could *284not be said that the police in Bumper acted in a threatening or coercive manner, for they did have the warrant they said they had; the decision not to rely on it was made long after the search, when the case came into court.10

That case makes it clear that police officers may not courteously order the subject of a search simply to stand aside while the officers carry out a search they have settled on. Yet there would be no coercion or brutality in giving that order. No interests that the Court today recognizes would be damaged in such a search. Thus, all the police must do is conduct what will inevitably be a charade of asking for consent. If they display any firmness at all, a verbal expression of assent will undoubtedly be forthcoming. I cannot believe that the protections of the Constitution mean so little.

II

My approach to the case is straightforward and, to me, obviously required by the notion of consent as a relinquishment of Fourth Amendment rights. I am at a loss to understand why consent “cannot be taken literally to mean a 'knowing’ choice.” Ante, at 224. In fact, I have difficulty in comprehending how a decision made without knowledge of available alternatives can be treated as a choice at all.

If consent to search means that a person has chosen to forgo his right to exclude the police from the place they seek to search, it follows that his consent cannot *285be considered a meaningful choice unless he knew that he could in fact exclude the police. The Court appears, however, to reject even the modest proposition that, if the subject of a search convinces the trier of fact that he did not know of his right to refuse assent to a police request for permission to search, the search must be held unconstitutional. For it says only that “knowledge of the right to refuse consent is one factor to be taken into account.” Ante, at 227. I find this incomprehensible. I can think of no other situation in which we would say that a person agreed to some course of action if he convinced us that he did not know that there was some other course he might have pursued. I would therefore hold, at a minimum, that the prosecution may not rely on a purported consent to search if the subject of the search did not know that he could refuse to give consent. That, I think, is the import of Bumper v. North Carolina, supra. Where the police claim authority to search yet in fact lack such authority, the subject does not know that he may permissibly refuse them entry, and it is this lack of knowledge that invalidates the consent.

If one accepts this view, the question then is a simple one: must the Government show that the subject knew of his rights, or must the subject show that he lacked such knowledge?

I think that any fair allocation of the burden would require that it be placed on the prosecution. On- this question, the Court indulges in what might be called the “straw man” method of adjudication. The Court responds to this suggestion by overinflating the burden. And, when it is suggested that the prosecution’s burden of proof could be easily satisfied if the police informed the subject of his rights, the Court responds by refusing to require the police to make a “detailed” inquiry. Ante, at 245. If the Court candidly faced the real *286question of allocating the burden of proof, neither of these maneuvers would be available to it.

If the burden is placed on the defendant, all the subject can do is to testify that he did not know of his rights. And I doubt that many trial judges will find for the defendant simply on the basis of that testimony. Precisely because the evidence is very hard to come by, courts have traditionally been reluctant to require a party to prove negatives such as the lack of knowledge. See, e. g., 9 J. Wigmore, Evidence 274 (3d ed. 1940); F. James, Civil Procedure § 7.8 (1965); E. Morgan, Some Problems of Proof Under the Anglo-American System of Litigation 75-76 (1956).

In contrast, there are several ways by which the subject’s knowledge of his rights may be shown. The subject may affirmatively demonstrate such knowledge by his responses at the time the search took place, as in United States v. Curíale, 414 F. 2d 744 (CA2 1969). Where, as in this case, the person giving consent is someone other than the defendant, the prosecution may require him to testify under oath. Denials of knowledge may be disproved by establishing that the subject had, in the recent past, demonstrated his knowledge of his rights, for example, by refusing entry when it was requested by the police. The prior experience or training of the subject might in some cases support an inference that he knew of his right to exclude the police.

The burden on the prosecutor would disappear, of course, if the police, at the time they requested consent to search, also told the subject that he had a right to refuse consent and that his decision to refuse would be respected. The Court’s assertions to the contrary notwithstanding, there is nothing impractical about this method of satisfying the prosecution’s burden of proof.11 *287It must be emphasized that the decision about informing the subject of his rights would lie with the officers seeking consent. If they believed that providing such information would impede their investigation, they might simply ask for consent, taking the risk that at some later date the prosecutor would be unable to prove that the subject knew of his rights or that some other basis for the search existed.

The Court contends that if an officer paused to inform the subject of his rights, the informality of the exchange would be destroyed. I doubt that a simple statement by an officer of an individual’s right to refuse consent would do much to alter the informality of the exchange, except to alert the subject to a fact that he surely is entitled to know. It is not without significance that for many years the agents of the Federal Bureau of Investigation have routinely informed subjects of their right to refuse consent, when they request consent to search. Note, Consent Searches: A Reappraisal After Miranda v. Arizona, 67 Col. L. Rev. 130, 143 n. 75 (1967) (citing letter from J. Edgar Hoover). The reported cases in which the police have informed subjects of their right to refuse consent show, also, that the information can be given without disrupting the casual flow of events. See, e. g., United States v. Miller, 395 F. 2d 116 (CA7 1968). What evidence there is, then, rather strongly suggests that nothing disastrous would happen if the police, before requesting consent, informed the subject that he had *288a right to refuse consent and that his refusal would be respected.12

I must conclude, with some reluctance, that when the Court speaks of practicality, what it really is talking of is the continued ability of the police to capitalize on the ignorance of citizens so as to accomplish by subterfuge what they could not achieve by relying only on the knowing relinquishment of constitutional rights. Of course it would be “practical” for the police to ignore the commands of the Fourth Amendment, if by practicality we mean that more criminals will be apprehended, even though the constitutional rights of innocent people also go by the board. But such a practical advantage is achieved only at the cost of permitting the police to disregard the limitations that the Constitution places on their behavior, a cost that a constitutional democracy cannot long absorb.

I find nothing in the opinion of the Court to dispel my belief that, in such a case, as the Court of Appeals for *289the Ninth Circuit said, “[u]nder many circumstances a reasonable person might read an officer’s ‘May I’ as the courteous expression of a demand backed by force of law.” 448 F. 2d, at 701. Most cases, in my view, are akin to Bumper v. North Carolina, 391 U. S. 543 (1968) : consent is ordinarily given as acquiescence in an implicit claim of authority to search. Permitting searches in such circumstances, without any assurance at all that the subject of the search knew that, by his consent, he was relinquishing his constitutional rights, is something that I cannot believe is sanctioned by the Constitution.

W-i I — H 1 — 1

The proper resolution of this case turns, I believe, on a realistic assessment of the nature of the interchange between citizens and the police, and of the practical import of allocating the burden of proof in one way rather than another. The Court seeks to escape such assessments by escalating its rhetoric to unwarranted heights, but no matter how forceful the adjectives the Court uses, it cannot avoid being judged by how well its image of these interchanges accords with reality. Although the Court says without real elaboration that it “cannot agree,” ante, at 248, the holding today confines the protection of the Fourth Amendment against searches conducted without probable cause to the sophisticated, the knowledgeable, and, I might add, the few.13 In the final analysis, the Court now sanctions a game of blindman’s buff, in which the police always have the upper hand, for the sake of nothing more than the convenience of *290the police. But the guarantees of the Fourth Amendment were never intended to shrink before such an ephemeral and changeable interest. The Framers of the Fourth Amendment struck the balance against this sort of convenience and in favor of certain basic civil rights. It is not for this Court to restrike that balance because of its own views of the needs of law enforcement officers. I fear that that is the effect of the Court's decision today.

It is regrettable that the obsession with validating searches like that conducted in this case, so evident in the Court’s hyperbole, has obscured the Court’s vision of how the Fourth Amendment was designed to govern the relationship between police and citizen in our society. I believe that experience and careful reflection show how narrow and inaccurate that vision is, and I respectfully dissent.

*179Justice Scalia delivered

the opinion of the Court.

In United States v. Matlock, 415 U. S. 164 (1974), this Court reaffirmed that a warrantless entry and search by law enforcement officers does not violate the Fourth Amendment’s proscription of “unreasonable searches and seizures” if the officers have obtained the consent of a third party who possesses common authority over the premises. The present case presents an issue we expressly reserved in Matlock, see id., at 177, n. 14: Whether a warrantless entry is valid when based upon the consent of a third party whom the police, at the time of the entry, reasonably believe to possess common authority over the premises, but who in fact does not do so.

I

Respondent Edward Rodriguez was arrested in his apartment by law. enforcement officers and charged with possession of illegal drugs. The police gained entry to the apartment with the consent and assistance of Gail Fischer, who had lived there with respondent for several months. The relevant facts leading to the arrest are as follows.

On July 26, 1985, police were summoned to the residence of Dorothy Jackson on South Wolcott in Chicago. They were met by Ms. Jackson’s daughter, Gail Fischer, who showed signs of a severe beating. She told the officers that she had been assaulted by respondent Edward Rodriguez earlier that day in an apartment on South California Avenue. Fischer stated that Rodriguez was then asleep in the apartment, and she consented to travel there with the police in order to unlock the door with her key so that the officers could enter and arrest him. During this conversation, Fischer several times referred to the apartment on South California as “our” apartment, and said that she had clothes and furniture there. It is unclear whether she indicated that she currently lived at the apartment, or only that she used to live there.

*180The police officers drove to the apartment on South California, accompanied by Fischer. They did not obtain an arrest warrant for Rodriguez, nor did they seek a search warrant for the apartment. At the apartment, Fischer unlocked the door with her key and gave the officers permission to enter. They moved through the door into the living room, where they observed in plain view drug paraphernalia and containers filled with white powder that they believed (correctly, as later analysis showed) to be cocaine. They proceeded to the bedroom, where they found Rodriguez asleep and discovered additional containers of white powder in two open attaché cases. The officers arrested Rodriguez and seized the drugs and related paraphernalia.

Rodriguez was charged with possession of a controlled substance with intent to deliver. He moved to suppress all evidence seized at the time of his arrest, claiming that Fischer had vacated the apartment several weeks earlier and had no authority to consent to the entry. The Cook County Circuit Court granted the motion, holding that at the time she consented to the entry Fischer did not have common authority over the apartment. The Court concluded that Fischer was not a “usual resident” but rather an “infrequent visitor” at the apartment on South California, based upon its findings that Fischer’s name was not on the lease, that she did not contribute to the rent, that she was not allowed to invite others to the apartment on her own, that she did not have access to the apartment when respondent was away, and that she had moved some of her possessions from the apartment. The Circuit Court also rejected the State’s contention that, even if Fischer did not possess common authority over the premises, there was no Fourth Amendment violation if the police reasonably believed at the time of their entry that Fischer possessed the authority to consent.

The Appellate Court of Illinois affirmed the Circuit Court in all respects. The Illinois Supreme Court denied the State’s petition for leave to appeal, 125 Ill. 2d 572, 537 *181N. E. 2d 816 (1989), and we granted certiorari. 493 U. S. 932 (1989).

II

The Fourth Amendment generally prohibits the warrant-less entry of a person’s home, whether to make an arrest or to search for specific objects. Payton v. New York, 445 U. S. 573 (1980); Johnson v. United States, 333 U. S. 10 (1948). The prohibition does not apply, however, to situations in which voluntary consent has been obtained, either from the individual whose property is searched, see Schneckloth v. Bustamonte, 412 U. S. 218 (1973), or from a third party who possesses common authority over the premises, see United States v. Matlock, supra, at 171. The State of Illinois contends that that exception applies in the present case.

As we stated in Matlock, supra, at 171, n. 7, “[cjommon authority” rests “on mutual use of the property by persons generally having joint access or control for most purposes . . . .” The burden of establishing that common authority rests upon the State. On the basis of this record, it is clear that burden was not sustained. The evidence showed that although Fischer, with her two small children, had lived with Rodriguez beginning in December 1984, she had moved out on July 1, 1985, almost a month before the search at issue here, and had gone to live with her mother. She took her and her children’s clothing with her, though leaving behind some furniture and household effects. During the period after July 1 she sometimes spent the night at Rodriguez’s apartment, but never invited her friends there, and never went there herself when he was not home. Her name was not on the lease nor did she contribute to the rent. She had a key to the apartment, which she said at trial she had taken without Rodriguez’s knowledge (though she testified at the preliminary hearing that Rodriguez had given her the key). On these facts the State has not established that, with respect to the South California apartment, Fischer had *182“joint access or control for most purposes.” To the contrary, the Appellate Court’s determination of no common authority over the apartment was obviously correct.

1 — l 1 — 1 1 — 1

A

The State contends that, even if Fischer did not in fact have authority to give consent, it suffices to validate the entry that the law enforcement officers reasonably believed she did. Before reaching the merits of that contention, we must consider a jurisdictional objection: that the decision below rests on an adequate and independent state ground. Respondent asserts that the Illinois Constitution provides greater protection than is afforded under the Fourth Amendment, and that the Appellate Court relied upon this when it determined that a reasonable belief by the police officers was insufficient.

When a state-court decision is clearly based on state law that is both adequate and independent, we will not review the decision. Michigan v. Long, 463 U. S. 1032, 1041 (1983). But when “a state court decision fairly appears to rest primarily on federal law, or to be interwoven with the federal law,” we require that it contain a “‘plain statement’ that [it] rests upon adequate and independent state grounds,” id., at 1040, 1042; otherwise, “we will accept as the most reasonable explanation that the state court decided the case the way it did because it believed that federal law required it to do so.” Id., at 1041. Here, the Appellate Court’s opinion contains no “plain statement” that its decision rests on state law. The opinion does not rely on (or even mention) any specific provision of the Illinois Constitution, nor even the Illinois Constitution generally. Even the Illinois cases cited by the opinion rely upon no constitutional provisions other than the Fourth and Fourteenth Amendments of the United States Constitution. We conclude that the Appellate Court of Illinois rested its decision on federal law.

*183B

On the merits of the issue, respondent asserts that permitting a reasonable belief of common authority to validate an entry would cause a defendant’s Fourth Amendment rights to be “vicariously waived.” Brief for Respondent 32. We disagree.

We have been unyielding in our insistence that a defendant’s waiver of his trial rights cannot be given effect unless it is “knowing” and “intelligent.” Colorado v. Spring, 479 U. S. 564, 574-575 (1987); Johnson v. Zerbst, 304 U. S. 458 (1938). We would assuredly not permit, therefore, evidence seized in violation of the Fourth Amendment to be introduced on the basis of a trial court’s mere “reasonable belief” — derived from statements by unauthorized persons — that the defendant has waived his objection. But one must make a distinction between, on the one hand, trial rights that derive from the violation of constitutional guarantees and, on the other hand, the nature of those constitutional guarantees themselves. As we said in Schneckloth:

“There is a vast difference between those rights that protect a fair criminal trial and the rights guaranteed under the Fourth Amendment. Nothing, either in the purposes behind requiring a ‘knowing’ and ‘intelligent’ waiver of trial rights, or in the practical application of such a requirement suggests that it ought to be extended to the constitutional guarantee against unreasonable searches and seizures.” 412 U. S., at 241.

What Rodriguez is assured by the trial right of the exclusionary rule, where it applies, is that no evidence seized in violation of the Fourth Amendment will be introduced at his trial unless he consents. What he is assured by the Fourth Amendment itself, however, is not that no government search of his house will occur unless he consents; but that no such search will occur that is “unreasonable." U. S. Const., Arndt. 4. There are various elements, of course, *184that can make a search of a person’s house “reasonable” — one of which is the consent of the person or his cotenant.. The essence of respondent’s argument is that we should impose upon this element a requirement that we have not imposed upon other elements that regularly compel government officers to exercise judgment regarding the facts: namely, the requirement that their judgment be not only responsible but correct.

The fundamental objective that alone validates all un-consented government searches is, of course, the seizure of persons who have committed or are about to commit crimes, or of evidence related to crimes. But “reasonableness,” with respect to this necessary element, does not demand that the government be factually correct in its assessment that that is what a search will produce. Warrants need only be supported by “probable cause,” which demands no more than a proper “assessment of probabilities in particular factual contexts . . . .” Illinois v. Gates, 462 U. S. 213, 232 (1983). If a magistrate, based upon seemingly reliable but factually inaccurate information, issues a warrant for the search of a house in which the sought-after felon is not present, has never been present, and was never likely to have been present, the owner of that house suffers one of the inconveniences we all expose ourselves to as the cost of living in a safe society; he does not suffer a violation of the Fourth Amendment.

Another element often, though not invariably, required in order to render an unconsented search “reasonable” is, of course, that the officer be authorized by a valid warrant. Here also we have not held that “reasonableness” precludes error with respect to those factual judgments that law enforcement officials are expected to make. In Maryland v. Garrison, 480 U. S. 79 (1987), a warrant supported by probable cause with respect to one apartment was erroneously issued for an entire floor that was divided (though not clearly) into two apartments. We upheld the search of the apartment not properly covered by the warrant. We said:

*185“[T]he validity of the search of respondent’s apartment pursuant to a warrant authorizing the search of the entire third floor depends on whether the officers’ failure to realize the overbreadth of the warrant was objectively understandable and reasonable. Here it unquestionably was. The objective facts available to the officers at the time suggested no distinction between [the suspect’s] apartment and the third-floor premises.” Id., at 88.

The ordinary requirement of a warrant is sometimes supplanted by other elements that render the unconsented search “reasonable.” Here also we have not held that the Fourth Amendment requires factual accuracy. A warrant is not needed, for example, where the search is incident to an arrest. In Hill v. California, 401 U. S. 797 (1971), we upheld a search incident to an arrest, even though the arrest was made of the wrong person. We said:

“The upshot was that the officers in good faith believed Miller was Hill and arrested him. They were quite wrong as it turned out, and subjective good-faith belief would not in itself justify either the arrest or the subsequent search. But sufficient probability, not certainty, is the touchstone of reasonableness under the Fourth Amendment and on the record before us the officers’ mistake was understandable and the arrest a reasonable response to the situation facing them at the time.” Id., at 803-804.

It would be superfluous to multiply these examples. It is apparent that in order to satisfy the “reasonableness” requirement of the Fourth Amendment, what is generally demanded of the many factual determinations that must regularly be made by agents of the government — whether the magistrate issuing a warrant, the police officer executing a warrant, or the police officer conducting a search or seizure under one of the exceptions to the warrant requirement — is not that they always be correct, but that they always be rea*186sonable. As we put it in Brinegar v. United States, 338 U. S. 160, 176 (1949):

“Because many situations which confront officers in the course of executing their duties are more or less ambiguous, room must be allowed for some mistakes on their part. But the mistakes must be those of reasonable men, acting on facts leading sensibly to their conclusions of probability.”

We see no reason to depart from this general rule with respect to facts bearing upon the authority to consent to a search. Whether the basis for such authority exists is the sort of recurring factual question to which law enforcement officials must be expected to apply their judgment; and all the Fourth Amendment requires is that they answer it reasonably. The Constitution is no more violated when officers enter without a warrant because they reasonably (though erroneously) believe that the person who has consented to their entry is a resident of the premises, than it is violated when they enter without a warrant because they reasonably (though erroneously) believe they are in pursuit of a violent felon who is about to escape. See Archibald v. Mosel, 677 F. 2d 5 (CA1 1982).*

*187 Stoner v. California, 376 U. S. 483 (1964), is in our view not to the contrary. There, in holding that police had improperly entered the defendant’s hotel room based on the consent of a hotel clerk, we stated that “the rights protected by the Fourth Amendment are not to be eroded ... by unrealistic doctrines of ‘apparent authority.’” Id., at 488. It is ambiguous, of course, whether the word “unrealistic” is descriptive or limiting — that is, whether we were condemning as unrealistic all reliance upon apparent authority, or whether we were condemning only such reliance upon apparent authority as is unrealistic. Similarly ambiguous is the opinion’s earlier statement that “there [is no] substance to the claim that the search was reasonable because the police, relying upon the night clerk’s expressions of consent, had a reasonable basis for the belief that the clerk had authority to consent to the search.” Ibid. Was there no substance to it because it failed as a matter of law, or because the facts could not possibly support it? At one point the opinion does seem to speak clearly:

“It is important to bear in mind that it was the petitioner’s constitutional right which was at stake here, and not the night clerk’s nor the hotel’s. It was a right, therefore, which only the petitioner could waive by word or deed, either directly or through an agent.” Id., at 489.

But as we have discussed, what is at issue when a claim of apparent consent is raised is not whether the right to be free of searches has been waived, but whether the right to be free of unreasonable searches has been violated. Even if one does not think the Stoner opinion had this subtlety in mind, the supposed clarity of its foregoing statement is immediately compromised, as follows:

*188“It is true that the night clerk clearly and unambiguously consented to the search. But there is nothing in the record to indicate that the police had any basis whatsoever to believe that the night clerk had been authorized by the petitioner to permit the police to search the petitioner’s room.” Ibid, (emphasis added).

The italicized language should have been deleted, of course, if the statement two sentences earlier meant that an appearance of authority could never validate a search. In the last analysis, one must admit that the rationale of Stoner was ambiguous — and perhaps deliberately so. It is at least a reasonable reading of the case, and perhaps a preferable one, that the police could not rely upon the obtained consent because they knew it came from a hotel clerk, knew that the room was rented and exclusively occupied by the defendant, and could not reasonably have believed that the former had general access to or control over the latter. Similarly ambiguous in its implications (the Court’s opinion does not even allude to, much less discuss the effects of, “reasonable belief”) is Chapman v. United States, 365 U. S. 610 (1961). In sum, we were correct in Matlock, 415 U. S., at 177, n. 14, when we regarded the present issue as unresolved.

As Stoner demonstrates, what we hold today does not suggest that law enforcement officers may always accept a person’s invitation to enter premises. Even when the invitation is accompanied by an explicit assertion that the person lives there, the surrounding circumstances could conceivably be such that a reasonable person would doubt its truth and not act upon it without further inquiry. As with other factual determinations bearing upon search and seizure, determination of consent to enter must “be judged against an objective standard: would the facts available to the officer at the moment . . . ‘warrant a man of reasonable caution in the belief’ ” that the consenting party had authority over the premises? Terry v. Ohio, 392 U. S. 1, 21-22 (1968). If not, then war-*189rantless entry without further inquiry is unlawful unless authority actually exists. But if so, the search is valid.

* * *

In the present case, the Appellate Court found it unnecessary to determine whether the officers reasonably believed that Fischer had the authority to consent, because it ruled as a matter of law that a reasonable belief could not validate the entry. Since we find that ruling to be in error, we remand for consideration of that question. The judgment of the Illinois Appellate Court is reversed, and the case is remanded for further proceedings not inconsistent with this opinion.

So ordered.

Justice Marshall,

with whom Justice Brennan and Justice Stevens join, dissenting.

Dorothy Jackson summoned police officers to her house to report that her daughter Gail Fischer had been beaten. Fischer told police that Ed Rodriguez, her boyfriend, was her assaulter. During an interview with Fischer, one of the officers asked if Rodriguez dealt in narcotics. Fischer did not respond. Fischer did agree, however, to the officers’ request to let them into Rodriguez’s apartment so that they could arrest him for battery. The police, without a warrant and despite the absence of an exigency, entered Rodriguez’s home to arrest him. As a result of their entry, the police discovered narcotics that the State subsequently sought to introduce in a drug prosecution against Rodriguez.

The majority agrees with the Illinois Appellate Court’s determination that Fischer did not have authority to consent to the officers’ entry of Rodriguez’s apartment. Ante, at 181-182. The Court holds that the warrantless entry into Rodriguez’s home was nonetheless valid if the officers reasonably believed that Fischer had authority to consent. Ante this page. The majority’s defense of this position rests on a misconception of the basis for third-party consent searches. That *190such searches do not give rise to claims of constitutional violations rests not on the premise that they are “reasonable” under the Fourth Amendment, see ante, at 183-184, but on the premise that a person may voluntarily limit his expectation of privacy by allowing others to exercise authority over his possessions. Cf. Katz v. United States, 389 U. S. 347, 351 (1967) (“What a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection”). Thus, an individual’s decision to permit another “joint access [to] or control [over the property] for most purposes,” United States v. Matlock, 415 U. S. 164, 171, n. 7 (1974), limits that individual’s reasonable expectation of privacy and to that extent limits his Fourth Amendment protections. Cf. Rakas v. Rlinois, 439 U. S. 128, 148 (1978) (because passenger in car lacked “legitimate expectation of privacy in the glove compartment,” Court did not decide whether search would violate Fourth Amendment rights of someone who had such expectation). If an individual has not so limited his expectation of privacy, the police may not dispense with the safeguards established by the Fourth Amendment.

The baseline for the reasonableness of a search or seizure in the home is the presence of a warrant. Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602 (1989). Indeed, “searches and seizures inside a home without a warrant are presumptively unreasonable.” Payton v. New York, 445 U. S. 573, 586 (1980). Exceptions to the warrant requirement must therefore serve “compelling” law enforcement goals. Mincey v. Arizona, 437 U. S. 385, 394 (1978). Because the sole law enforcement purpose underlying third-party consent searches is avoiding the inconvenience of securing a warrant, a departure from the warrant requirement is not justified simply because an officer reasonably believes a third party has consented to a search of the defendant’s home. In holding otherwise, the majority ignores our longstanding view that “the informed and deliberate determina*191tions of magistrates ... as to what searches and seizures are permissible under the Constitution are to be preferred over the hurried action of officers and others who may happen to make arrests.” United States v. Lefkowitz, 285 U. S. 452, 464 (1932).

I

The Fourth Amendment provides that “[t]he right of the people to be secure in their . . . houses . . . shall not be violated.” We have recognized that the “physical entry of the home is the chief evil against which the wording of the Fourth Amendment is directed.” United States v. United States District Court, Eastern District of Michigan, 407 U. S. 297, 313 (1972). We have further held that “a search or seizure carried out on a suspect’s premises without a warrant is per se unreasonable, unless the police can show that it falls within one of a carefully defined set of exceptions.” Coolidge v. New Hampshire, 403 U. S. 443, 474 (1971). Those exceptions must be crafted in light of the warrant requirement’s purposes. As this Court stated in McDonald v. United States, 335 U. S. 451 (1948):

“The presence of a search warrant serves a high function. Absent some grave emergency, the Fourth Amendment has interposed a magistrate between the citizen and the police. This was done not to shield criminals nor to make the home a safe haven for illegal activities. It was done so that an objective mind might weigh the need to invade that privacy in order to enforce the law. The right of privacy was deemed too precious to entrust to the discretion of those whose job is the detection of crime and the arrest of criminals.” Id., at 455-456.

The Court has tolerated departures from the warrant requirement only when an exigency makes a warrantless search imperative to the safety of the police and of the community. See, e. g., id., at 456 (“We cannot be true to that *192constitutional requirement and excuse the absence of a search warrant without a showing by those who seek exemption from the constitutional mandate that the exigencies of the situation made that course imperative”); Warden v. Hayden, 387 U. S. 294 (1967) (hot pursuit); Chimel v. California, 395 U. S. 752 (1969) (interest in officers’ safety justifies search incident to an arrest); Michigan v. Tyler, 436 U. S. 499, 509 (1978) (“compelling need for official action and no time to secure a warrant” justifies warrantless entry of burning building). The Court has often heard, and steadfastly rejected, the invitation to carve out further exceptions to the warrant requirement for searches of the home because of the burdens on police investigation and prosecution of crime. Our rejection of such claims is not due to a lack of appreciation of the difficulty and importance of effective law enforcement, but rather to our firm commitment to “the view of those who wrote the Bill of Rights that the privacy of a person’s home and property may not be totally sacrificed in the name of maximum simplicity in enforcement of the criminal law.” Mincey, supra, at 393 (citing United States v. Chadwick, 433 U. S. 1, 6-11 (1977)).

In the absence of an exigency, then, warrantless home searches and seizures are unreasonable under the Fourth Amendment. The weighty constitutional interest in preventing unauthorized intrusions into the home overrides any law enforcement interest in relying on the reasonable but potentially mistaken belief that a third party has authority to consent to such a search or seizure. Indeed, as the present case illustrates, only the minimal interest in avoiding the inconvenience of obtaining a warrant weighs in on the law enforcement side.

Against this law enforcement interest in expediting arrests is “the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion.” Silverman v. United States, 365 U. S. 505, 511 (1961). To be sure, in some cases in which police officers reasonably rely on a *193third party’s consent, the consent will prove valid, no intrusion will result, and the police will have been spared the inconvenience of securing a warrant. But in other cases, such as this one, the authority claimed by the third party will be false. The reasonableness of police conduct must be measured in light of the possibility that the target has not consented. Where “[n]o reason is offered for not obtaining a search warrant except the inconvenience to the officers and some slight delay necessary to prepare papers and present the evidence to a magistrate,” the Constitution demands that the warrant procedure be observed. Johnson v. United States, 333 U. S. 10, 15 (1948). The concerns of expediting police work and avoiding paperwork “are never very convincing reasons and, in these circumstances, certainly are not enough to by-pass the constitutional requirement.” Ibid. In this case, as in Johnson, “[n]o suspect was fleeing or likely to take flight. The search was of permanent premises, not of a movable vehicle. No evidence or contraband was threatened with removal or destruction .... If the officers in this case were excused from the constitutional duty of presenting their evidence to a magistrate, it is difficult to think of a case in which it should be required.” Ibid.

Unlike searches conducted pursuant to the recognized exceptions to the warrant requirement, see supra, at 191-192, third-party consent searches are not based on an exigency and therefore serve no compelling social goal. Police officers, when faced with the choice of relying on consent by a third party or securing a warrant, should secure a warrant and must therefore accept the risk of error should they instead choose to rely on consent.

II

Our prior cases discussing searches based on third-party consent have never suggested that such searches are “reasonable.” In United States v. Matlock, this Court upheld a warrantless search conducted pursuant to the consent of a *194third party who was living with the defendant. The Court rejected the defendant’s challenge to the search, stating that a person who permits others to have “joint access or control for most purposes . . . assume[s] the risk that [such persons] might permit the common area to be searched.” 415 U. S., at 171, n. 7; see also Frazier v. Cupp, 394 U. S. 731, 740 (1969) (holding that defendant who left a duffel bag at another’s house and allowed joint use of the bag “assumed the risk that [the person] would allow someone else to look inside”). As the Court’s assumption-of-risk analysis makes clear, third-party consent limits a person’s ability to challenge the reasonableness of the search only because that person voluntarily has relinquished some of his expectation of privacy by sharing access or control over his property with another person.

A search conducted pursuant to an officer’s reasonable but mistaken belief that a third party had authority to consent is thus on an entirely different constitutional footing from one based on the consent of a third party who in fact has such authority. Even if the officers reasonably believed that Fischer had authority to consent, she did not, and Rodriguez’s expectation of privacy was therefore undiminished. Rodriguez accordingly can challenge the warrantless intrusion into his home as a violation of the Fourth Amendment. This conclusion flows directly from Stoner v. California, 376 U. S. 483 (1964). There, the Court required the suppression of evidence seized in reliance on a hotel clerk’s consent to a war-rantless search of a guest’s room. The Court reasoned that the guest’s right to be free of unwarranted intrusion “was a right. . . which only [he] could waive by word or deed, either directly or through an agent.” Id., at 489. Accordingly, the Court rejected resort to “unrealistic doctrines of ‘apparent authority’ ” as a means of upholding the search to which the guest had not consented. Id., at 488.1

*195III

Acknowledging that the third party in this case lacked authority to consent, the majority seeks to rely on cases suggesting that reasonable but mistaken factual judgments by police will not invalidate otherwise reasonable searches. The majority reads these cases as establishing a “general rule” that “what is generally demanded of the many factual determinations that must regularly be made by agents of the government — whether the magistrate issuing a warrant, the police officer executing a warrant, or the police officer conducting a search or seizure under one of the exceptions to the *196warrant requirement — is not that they always be correct, but that they always be reasonable.” Ante, at 185-186.

The majority’s assertion, however, is premised on the erroneous assumption that third-party consent searches are generally reasonable. The cases the majority cites thus provide no support for its holding. In Brinegar v. United States, 338 U. S. 160 (1949), for example, the Court confirmed the unremarkable proposition that police need only probable cause, not absolute certainty, to justify the arrest of a suspect on a highway. As Brinegar makes clear, the possibility of factual error is built into the probable cause standard, and such a standard, by its very definition, will in some cases result in the arrest of a suspect who has not actually committed a crime. Because probable cause defines the reasonableness of searches and seizures outside of the home, a search is reasonable under the Fourth Amendment whenever that standard is met, notwithstanding the possibility of “mistakes” on the part of police. Id., at 176. In contrast, our cases have already struck the balance against warrantless home intrusions in the absence of an exigency. See supra, at 191-192. Because reasonable factual errors by law enforcement officers will not validate unreasonable searches, the reasonableness of the officer’s mistaken belief that the third party had authority to consent is irrelevant.2

*197The majority’s reliance on Maryland v. Garrison, 480 U. S. 79 (1987), is also misplaced. In Garrison, the police obtained a valid warrant for the search of the “third floor apartment” of a building whose third floor in fact housed two apartments. Id., at 80. Although the police had probable cause to search only one of the apartments, they entered both apartments because “[t]he objective facts available to the officers at the time suggested no distinction between [the apartment for which they legitimately had the warrant and the entire third floor].” Id., at 88. The Court held that the officers’ reasonable mistake of fact did not render the search unconstitutional. Id., at 88-89. As in Brinegar, the Court’s decision was premised on the general reasonableness of the type of police action involved. Because searches based on warrants are generally reasonable, the officers’ reasonable mistake of fact did not render their search “unreasonable.” This reasoning is evident in the Court’s conclusion that little would be gained by adopting additional burdens “over and above the bedrock requirement that, with the exceptions we have traced in our cases, the police may conduct searches only pursuant to a reasonably detailed warrant.” Garrison, supra, at 89, n. 14.

Garrison, like Brinegar, thus tells us nothing about the reasonableness under the Fourth Amendment of a warrant-less arrest in the home based on an officer’s reasonable but mistaken belief that the third party consenting to the arrest was empowered to do so. The majority’s glib assertion that “[i]t would be superfluous to multiply” its citations to cases like Brinegar, Hill, and Garrison, ante, at 185, is thus correct, but for a reason entirely different than the majority suggests. Those cases provide no illumination of the issue raised in this case, and further citation to like cases would be *198as superfluous as the discussion on which the majority’s conclusion presently depends.

IV

Our cases demonstrate that third-party consent searches are free from constitutional challenge only to the extent that they rest on consent by a party empowered to do so. The majority’s conclusion to the contrary ignores the legitimate expectations of privacy on which individuals are entitled to rely. That a person who allows another joint access to his property thereby limits his expectation of privacy does not justify trampling the rights of a person who has not similarly relinquished any of his privacy expectation.

Instead of judging the validity of consent searches, as we have in the past, based on whether a defendant has in fact limited his expectation of privacy, the Court today carves out an additional exception to the warrant requirement for third-party consent searches without pausing to consider whether “ ‘the exigencies of the situation’ make the needs of law enforcement so compelling that the warrantless search is objectively reasonable under the Fourth Amendment,” Mincey, 437 U. S., at 394 (citations omitted). Where this free-floating creation of “reasonable” exceptions to the warrant requirement will end, now that the Court has departed from the balancing approach that has long been part of our Fourth Amendment jurisprudence, is unclear. But by allowing a person to be subjected to a warrantless search in his home without his consent and without exigency, the majority has taken away some of the liberty that the Fourth Amendment was designed to protect.

*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.

Chief Justice Rehnquist

delivered the opinion of the Court.

On February 10, 1984, a police officer in Boulder, Colorado, arrested respondent Steven Lee Bertine for driving while under the influence of alcohol. After Bertine was taken into custody and before the arrival of a tow truck to take Bertine’s van to an impoundment lot,1 a backup officer *369inventoried the contents of the van. The officer opened a closed backpack in which he found controlled substances, cocaine paraphernalia, and a large amount of cash. Bertine was subsequently charged with driving while under the influence of alcohol, unlawful possession of cocaine with intent to dispense, sell, and distribute, and unlawful possession of methaqualone. We are asked to decide whether the Fourth Amendment prohibits the State from proving these charges with the evidence discovered during the inventory of Ber-tine’s van. We hold that it does not.

The backup officer inventoried the van in accordance with local police procedures, which require a detailed inspection and inventory of impounded vehicles. He found the backpack directly behind the frontseat of the van. Inside the pack, the officer observed a nylon bag containing metal canisters. Opening the canisters, the officer discovered that they contained cocaine, methaqualone tablets, cocaine paraphernalia, and $700 in cash. In an outside zippered pouch of the backpack, he also found $210 in cash in a sealed envelope. After completing the inventory of the van, the officer had the van towed to an impound lot and brought the backpack, money, and contraband to the police station.

After Bertine was charged with the offenses described above, he moved to suppress the evidence found during the inventory search on the ground, inter alia, that the search of the closed backpack and containers exceeded the permissible scope of such a search under the Fourth Amendment. The Colorado trial court ruled that probable causé supported Bertine’s arrest and that the police officers had made the decisions to impound the vehicle and to conduct a thorough inventory search in good faith. Although noting that the inventory of the vehicle was performed in a “somewhat slipshod” manner, the District Court concluded that “the search of the backpack was done for the purpose of protecting the *370owner’s property, protection of the police from subsequent claims of loss or stolen property, and the protection of the police from dangerous instrumentalities.” App. 81-83. The court observed that the standard procedures for impounding vehicles mandated a “detailed inventory involving the opening of containers and the listing of [their] contents.” Id., at 81. Based on these findings, the court determined that the inventory search did not violate Bertine’s rights under the Fourth Amendment of the United States Constitution. Id., at 83. The court, nevertheless, granted Bertine’s motion to suppress, holding that the inventory search violated the Colorado Constitution.

On the State’s interlocutory appeal, the Supreme Court of Colorado affirmed. 706 P. 2d 411 (1985). In contrast to the District Court, however, the Colorado Supreme Court premised its ruling on the United States Constitution. The court recognized that in South Dakota v. Opperman, 428 U. S. 364 (1976), we had held inventory searches of automobiles to be consistent with the Fourth Amendment, and that in Illinois v. Lafayette, 462 U. S. 640 (1983), we had held that the inventory search of personal effects of an arrestee at a police station was also permissible under that Amendment. The Supreme Court of Colorado felt, however, that our decisions in Arkansas v. Sanders, 442 U. S. 753 (1979), and United States v. Chadwick, 433 U. S. 1 (1977), holding searches of closed trunks and suitcases to violate the Fourth Amendment, meant that Opperman and Lafayette did not govern this case.2

We granted certiorari to consider the important and recurring question of federal law decided by the Colorado Supreme *371Court.3 475 U. S. 1081 (1986). As that court recognized, inventory searches are now a well-defined exception to the warrant requirement of the Fourth Amendment. See Lafayette, supra, at 643; Opperman, supra, at 367-376. The policies behind the warrant requirement are not implicated in an inventory search, Opperman, 428 U. S., at 370, n. 5, nor is the related concept of probable cause:

“The standard of probable cause is peculiarly related to criminal investigations, not routine, noncriminal procedures. . . . The probable-cause approach is unhelpful when analysis centers upon the reasonableness of routine administrative caretaking functions, particularly when no claim is made that the protective procedures are a subterfuge for criminal investigations.” Ibid.

See also United States v. Chadwick, supra, at 10, n. 5. For these reasons, the Colorado Supreme Court’s reliance on Arkansas v. Sanders, supra, and United States v. Chadwick, supra, was incorrect. Both of these cases concerned searches solely for the purpose of investigating criminal conduct, with the validity of the searches therefore dependent on the application of the probable-cause and warrant requirements of the Fourth Amendment.

By contrast, an inventory search may be “reasonable” under the Fourth Amendment even though it is not conducted pursuant to a warrant based upon probable cause. In *372 Opperman, this Court assessed the reasonableness of an inventory search of the glove compartment in an abandoned automobile impounded by the police. We found that inventory procedures serve to protect an owner’s property while it is in the custody of the police, to insure against claims of lost, stolen, or vandalized property, and to guard the police from danger. In light of these strong governmental interests and the diminished expectation of privacy in an automobile, we upheld the search. In reaching this decision, we observed that our cases accorded deference to police caretaking procedures designed to secure and protect vehicles and their contents within police custody. See Cooper v. California, 386 U. S. 58, 61-62 (1967); Harris v. United States, 390 U. S. 234, 236 (1968); Cady v. Dombrowski, 413 U. S. 433, 447-448 (1973).4

In our more recent decision, Lafayette, a police officer conducted an inventory search of the contents of a shoulder bag in the possession of an individual being taken into custody. In deciding whether this search was reasonable, we recognized that the search served legitimate governmental interests similar to those identified in Opperman. We determined that those interests outweighed the individual’s Fourth Amendment interests and upheld the search.

In the present case, as in Opperman and Lafayette, there was no showing that the police, who were following standardized procedures, acted in bad faith or for the sole purpose of investigation. In addition, the governmental interests justifying the inventory searches in Opperman and Lafayette are *373nearly the same as those which obtain here. In each case, the police were potentially responsible for the property taken into their custody. By securing the property, the police protected the property from unauthorized interference. Knowledge of the precise nature of the property helped guard against claims of theft, vandalism, or negligence. Such knowledge also helped to avert any danger to police or others that may have been posed by the property.5

The Supreme Court of Colorado opined that Lafayette was not controlling here because there was no danger of introducing contraband or weapons into a jail facility. Our opinion in Lafayette, however, did not suggest that the station-house setting of the inventory search was critical to our holding in that case. Both in the present case and in Lafayette, the common governmental interests described above were served by the inventory searches.

The Supreme Court of Colorado also expressed the view that the search in this case was unreasonable because Bertine’s van was towed to a secure, lighted facility and because Bertine himself could have been offered the opportunity to make other arrangements for the safekeeping of his property. But the security of the storage facility does not completely eliminate the need for inventorying; the police may still wish to protect themselves or the owners of the lot against false claims of theft or dangerous instrumentalities. And while giving Bertine an opportunity to make alterna*374tive arrangements would undoubtedly have been possible, we said in Lafayette:

“[T]he real question is not what ‘could have been achieved,’ but whether the Fourth Amendment requires such steps ....

“The reasonableness of any particular governmental activity does not necessarily or invariably turn on the existence of alternative ‘less intrusive’ means.” Lafayette, 462 U. S., at 647 (emphasis in original).

See Cady v. Dombrowski, supra, at 447; United States v. Martinez-Fuerte, 428 U. S. 543, 557, n. 12 (1976). We conclude that here, as in Lafayette, reasonable police regulations relating to inventory procedures administered in good faith satisfy the Fourth Amendment, even though courts might as a matter of hindsight be able to devise equally reasonable rules requiring a different procedure.6

The Supreme Court of Colorado also thought it necessary to require that police, before inventorying a container, weigh the strength of the individual’s privacy interest in the container against the possibility that the container might serve as a repository for dangerous or valuable items. We think that such a requirement is contrary to our decisions in *375 Opperman and Lafayette, and by analogy to our decision in United States v. Ross, 456 U. S. 798 (1982):

“Even if less intrusive means existed of protecting some particular types of property, it would be unreasonable to expect police officers in the everyday course of business to make fine and subtle distinctions in deciding which containers or items may be searched and which must be sealed as a unit.” Lafayette, supra, at 648.

“When a legitimate search is under way, and when its purpose and its limits have been precisely defined, nice distinctions between closets, drawers, and containers, in the case of a home, or between glove compartments, upholstered seats, trunks, and wrapped packages, in the case of a vehicle, must give way to the interest in the prompt and efficient completion of the task at hand.” United States v. Ross, supra, at 821.

We reaffirm these principles here: “‘[a] single familiar standard is essential to guide police officers, who have only limited time and expertise to reflect on and balance the social and individual interests involved in the specific circumstances they confront.’ ” Lafayette, supra, at 648 (quoting New York v. Belton, 453 U. S. 454, 458 (1981)).

Bertine finally argues that the inventory search of his van was unconstitutional because departmental regulations gave the police officers discretion to choose between impounding his van and parking and locking it in a public parking place. The Supreme Court of Colorado did not rely on this argument in reaching its conclusion, and we reject it. Nothing in Opperman or Lafayette prohibits the exercise of police discretion so long as that discretion is exercised according to standard criteria and on the basis of something other than suspicion of evidence of criminal activity. Here, the discretion afforded the Boulder police was exercised in light of *376standardized criteria, related to the feasibility and appropriateness of parking and locking a vehicle rather than impounding it.7 There was no showing that the police chose to impound Bertine’s van in order to investigate suspected criminal activity.

While both Opperman and Lafayette are distinguishable from the present case on their facts, we think that the principles enunciated in those cases govern the present one. The judgment of the Supreme Court of Colorado is therefore

Reversed.

Justice Blackmun,

with whom Justice Powell and Justice O’Connor join, concurring.

The Court today holds that police officers may open closed containers while conducting a routine inventory search of an impounded vehicle. I join the Court’s opinion, but write separately to underscore the importance of having such inventories conducted only pursuant to standardized police procedures. The underlying rationale for allowing an inventory exception to the Fourth Amendment warrant rule is that police officers are not vested with discretion to determine the scope of the inventory search. See South Dakota v. Opperman, 428 U. S. 364, 382-383 (1976) (Powell, J., concurring). This absence of discretion ensures that inventory searches will not be used as a purposeful and general means of discovering evidence of crime. Thus, it is permis*377sible for police officers to open closed containers in an inventory search only if they are following standard police procedures that mandate the opening of such containers in every impounded vehicle. As the Court emphasizes, the trial court in this case found that the Police Department’s standard procedures did mandate the opening of closed containers and the fisting of their contents. See ante, at 374, n. 6.

Justice Marshall,

with whom Justice Brennan joins, dissenting.

Recognizing that “both Opperman and Lafayette are distinguishable from the present case on their facts,” ante, at 376, the majority applies the balancing test enunciated in those cases to uphold as reasonable the inventory of a closed container in a car impounded when its driver was placed under arrest. However, the distinctive facts of this case require a different result. This search — it cannot legitimately be labeled an inventory — was unreasonable and violated the Fourth Amendment. Unlike the inventories in South Dakota v. Opperman, 428 U. S. 364 (1976), and Illinois v. Lafayette, 462 U. S. 640 (1983), it was not conducted according to standardized procedures. Furthermore, the governmental interests justifying the intrusion are significantly weaker than the interests identified in either Opperman or Lafayette and the expectation of privacy is considerably stronger.

I

As the Court acknowledges, ante, at 374, and n. 6, and 375-376, inventory searches are reasonable only if conducted according to standardized procedures. In both Opperman and Lafayette, the Court relied on the absence of police discretion in determining that the inventory searches in question were reasonable. Chief Justice Burger’s opinion in Opperman repeatedly referred to this standardized nature of inventory procedures. See 428 U. S., at 369, 372, 376. Justice Powell’s concurring opinion in that case also *378stressed that “no significant discretion is placed in the hands of the individual officer: he usually has no choice as to the subject of the search or its scope.” Id., at 384 (footnote omitted). Similarly, the Court in Lafayette emphasized the standardized procedure under which the station-house inventory was conducted. See 462 U. S., at 646, 647, 648; see also id., at 649 (Marshall, J., concurring in judgment). In assessing the reasonableness of searches conducted in limited situations such as these, where we do not require probable cause or a warrant, we have consistently emphasized the need for such set procedures: “standardless and unconstrained discretion is the evil the Court has discerned when in previous cases it has insisted that the discretion of the official in the field be circumscribed, at least to some extent.” Delaware v. Prouse, 440 U. S. 648, 661 (1979). See Almeida-Sanchez v. United States, 413 U. S. 266, 270 (1973); Cady v. Dombrowski, 413 U. S. 433, 443 (1973); Harris v. United States, 390 U. S. 234, 235 (1968); Camara v. Municipal Court, 387 U. S. 523, 532-533 (1967).

The Court today attempts to evade these clear prohibitions on unfettered police discretion by declaring that “the discretion afforded the Boulder police was exercised in light of standardized criteria, related to the feasibility and appropriateness of parking and locking a vehicle rather than impounding it.” Ante, at 375-376. This vital assertion is flatly contradicted by the record in this case. The officer who conducted the inventory, Officer Reichenbach, testified at the suppression hearing that the decision not to “park and lock” respondent’s vehicle was his “own individual discretionary decision.” Tr. 76. Indeed, application of these supposedly standardized “criteria” upon which the Court so heavily relies would have yielded a different result in this case. Since there was ample public parking adjacent to the intersection where respondent was stopped, consideration of “feasibility” would certainly have militated in favor of the “park and lock” *379option, not against it. I do not comprehend how consideration of “appropriateness” serves to channel a field officer’s discretion; nonetheless, the “park and lock” option would seem particularly appropriate in this case, where respondent was stopped for a traffic offense and was not likely to be in custody for a significant length of time.

Indeed, the record indicates that no standardized criteria limit a Boulder police officer’s discretion. According to a departmental directive,1 after placing a driver under arrest, an officer has three options for disposing of the vehicle. First, he can allow a third party to take custody.2 Second, the officer or the driver (depending on the nature of the arrest) may take the car to the nearest public parking facility, lock it, and take the keys.3 Finally, the officer can do what was done in *380this case: impound the vehicle, and search and inventory its contents, including closed containers.4

Under the first option, the police have no occasion to search the automobile. Under'the “park and lock” option, “[c]losed containers that give no indication of containing either valuables or a weapon may not be opened and the contents searched (i. e., inventoried).” App. 92-93 (emphasis added). Only if the police choose the third option are they entitled to search closed containers in the vehicle. Where the vehicle is not itself evidence of a crime,5 as in this case, the police apparently have totally unbridled discretion as to which procedure to use. See 706 P. 2d 411, 413, n. 3 (Colo. 1985) (“[T]he Boulder Police Department’s regulations and rules do not require that an automobile be inventoried and searched in accordance with the procedures followed in this *381case”). Consistent with this conclusion, Officer Reichenbach testified that such decisions were left to the discretion of the officer on the scene. App. 60.

Once a Boulder police officer has made this initial completely discretionary decision to impound a vehicle, he is given little guidance as to which areas to search and what sort of items to inventory. The arresting officer, Officer Toporek, testified at the suppression hearing as to what items would be inventoried: “That would I think be very individualistic as far as what an officer may or may not go into. I think whatever arouses his suspicious [sic] as far as what may be contained in any type of article in the car.” Id., at 78. In application, these so-called procedures left the breadth of the “inventory” to the whim of the individual officer. Clearly, “[t]he practical effect of this system is to leave the [owner] subject to the discretion of the official in the field.” Camara v. Municipal Court, 387 U. S., at 532.

Inventory searches are not subject to the warrant requirement because they are conducted by the government as part of a “community caretaking” function, “totally divorced from the detection, investigation, or acquisition of evidence relating to the violation of a criminal statute.” Cady v. Dombrowski, 413 U. S., at 441. Standardized procedures are necessary to ensure that this narrow exception is not improperly used to justify, after the fact, a warrantless investigative foray. Accordingly, to invalidate a search that is conducted without established procedures, it is not necessary to establish that the police actually acted in bad faith, or that the inventory was in fact a “pretext.” By allowing the police unfettered discretion, Boulder’s discretionary scheme, like the random spot checks in Delaware v. Prouse, is unreasonable because of the “‘grave danger’ of abuse of discretion.” 440 U. S., at 662.

II

In South Dakota v. Opperman, 428 U. S. 364 (1976), and Illinois v. Lafayette, 462 U. S. 640 (1983), both of which *382involved inventories conducted pursuant to standardized procedures, we balanced the individual’s expectation of privacy against the government’s interests to determine whether the search was reasonable. Even if the search in this case did constitute a legitimate inventory, it would nonetheless be unreasonable under this analysis.

A

The Court greatly overstates the justifications for the inventory exception to the Fourth Amendment. Chief Justice Burger, writing for the majority in Opperman, relied on three governmental interests to justify the inventory search of an unlocked glove compartment in an automobile impounded for overtime parking: (i) “the protection of the owner’s property while it remains in police custody”; (ii) “the protection of the police against claims or disputes over lost or stolen property”; and (iii) “the protection of the police from potential danger.” 428 U. S., at 369. The majority finds that “nearly the same” interests obtain in this case. See ante, at 373. As Justice Powell’s concurring opinion in Opperman reveals, however, only the first of these interests is actually served by an automobile inventory search.

The protection-against-claims interest did not justify the inventory search either in Opperman, see 428 U. S., at 378, n. 3 (Powell, J., concurring), or in this case. As the majority apparently concedes, ante, at 373, the use of secure im-poundment facilities effectively eliminates this concern.6 As *383to false claims, “inventories are [not] a completely effective means of discouraging false claims, since there remains the possibility of accompanying such claims with an assertion that an item was stolen prior to the inventory or was intentionally omitted from the police records.” 428 U. S., at 378-379 (Powell, J., concurring). See also id., at 391, and nn. 9 and 10 (Marshall, J., dissenting); 2 W. LaFave, Search and Seizure § 5.5, p. 360, n. 50 (1978 and Supp. 1986).

Officer Reichenbach’s inventory in this case would not have protected the police against claims lodged by respondent, false or otherwise. Indeed, the trial court’s characterization of the inventory as “slip-shod” is the height of understatement. For example, Officer Reichenbach failed to list $150 in cash found in respondent’s wallet or the contents of a sealed envelope marked “rent,” $210, in the relevant section of the property form. Tr. 40-41; App. 41-42. His reports make no reference to other items of value, including respondent’s credit cards, and a converter, a hydraulic jack, and a set of tire chains, worth a total of $125. Tr. 41, 62-63. The $700 in cash found in respondent’s backpack, along with the contraband, appeared only on a property form completed later by someone other than Officer Reichenbach. Id., at 81-82. The interior of the vehicle was lef t in disarray, id., at 99, and the officer “inadvertently” retained respondent’s keys — including his house keys — for two days following his arrest. Id., at 116, 133-134.

The third interest — protecting the police from potential danger — failed to receive the endorsement of a majority of the Court in Opperman. After noting that “there is little danger associated with impounding unsearched vehicles,” Justice Powell recognized that “there does not appear to be any effective way of identifying in advance those circumstances or classes of automobile impoundments which represent a greater risk.” 428 U. S., at 378. See also id., at 390 (Marshall, J., dissenting) (safety rationale “cannot justify the search of every car upon the basis of undifferentiated pos*384sibility of harm”). As with the charge of overtime parking in Opperman, there is nothing in the nature of the offense for which respondent was arrested that suggests he was likely to be carrying weapons, explosives, or other dangerous items. Cf. Cady v. Dombrowski, 413 U. S., at 436-437 (police reasonably believed that the defendant’s service revolver was in the car). Not only is protecting the police from dangerous instrumentalities an attenuated justification for most automobile inventory searches, but opening closed containers to inventory the contents can only increase the risk. In the words of the District Court in United States v. Cooper, 428 F. Supp. 652, 654-655 (SD Ohio 1977): “The argument that the search was necessary to avoid a possible booby-trap is . . . easily refuted. No sane individual inspects for booby-traps by simply opening the container.”

Thus, only the government’s interest in protecting the owner’s property actually justifies an inventory search of an impounded vehicle. See 428 U. S., at 379 (Powell, J., concurring); id., at 391 (Marshall, J., dissenting). While I continue to believe that preservation of property does not outweigh the privacy and security interests protected by the Fourth Amendment, I fail to see how preservation can even be asserted as a justification for the search in this case. In Opperman, the owner of the impounded car was not available to safeguard his possessions, see id., at 375, and it could plausibly be argued that, in his absence, the police were entitled to act for his presumed benefit. See also Cady v. Dombrowski, supra, at 436 (comatose defendant). When the police conducted the inventory in Opperman, they could not predict how long the car would be left in their possession. See 428 U. S., at 379 (Powell, J., concurring) (“[M]any owners might leave valuables in their automobiles temporarily that they would not leave there unattended for the several days that police custody may last”); cf. Cooper v. California, 386 U. S. 58, 61 (1967) (police retained car for four months pending forfeiture; length of time considered by the Court in as*385sessing reasonableness of inventory). In this case, however, the owner was “present to make other arrangements for the safekeeping of his belongings,” Opperman, 428 U. S., at 375, yet the police made no attempt to ascertain whether in fact he wanted them to “safeguard” his property. Furthermore, since respondent was charged with a traffic offense, he was unlikely to remain in custody for more than a few hours. He might well have been willing to leave his valuables unattended in the locked van for such a short period of time. See Tr. 110 (had he been given the choice, respondent indicated at the suppression hearing that he “would have parked [the van] in the lot across the street [and] [h]ad somebody come and get it”).

Thus, the government’s interests in this case are weaker than in Opperman, but the search here is much more intrusive. Opperman did not involve a search of closed containers or other items that “ ‘touch upon intimate areas of an individual’s personal affairs,’” 428 U. S., at 380, and n. 7 (Powell, J., concurring) (quoting California Bankers Assn. v. Shultz, 416 U. S. 21, 78-79 (1974) (Powell, J., concurring)); nor can the Court’s opinion be read to authorize the inspection of “containers which might themselves be sealed, removed and secured without further intrusion.” 428 U. S., at 388, n. 6 (Marshall, J., dissenting). To expand the Opperman rationale to include containers in which the owner clearly has a reasonable expectation of privacy, the Court relies on Illinois v. Lafayette, 462 U. S. 640 (1983). Such reb-anee is fundamentally misplaced, however; the inventory in Lafayette was justified by considerations which are totally absent in this context.

In Lafayette, we upheld a station-house inventory search of an arrestee’s shoulder bag. Notwithstanding the Court’s assertions to the contrary, ante, at 373, the inventory in that case was justified primarily by compelling governmental interests unique to the station house, preincarceration context. There is a powerful interest in preventing the introduction *386of contraband or weapons into a jail.7 “Arrested persons have also been known to injure themselves — or others — with belts, knives, drugs, or other items on their person while being detained. Dangerous instrumentalities — such as razor blades, bombs, or weapons — can be concealed in innocent-looking articles taken from the arrestee’s possession.” 462 U. S., at 646. Removing such items from persons about to be incarcerated is necessary to reasonable jail security; once these items have been identified and removed, “inventorying them is an entirely reasonable administrative procedure.” Ibid. Although Lafayette also involved the property justifications relied on in Opperman, I do not believe it can fairly be read to expand the scope of inventory searches where the pressing security concerns of the station house are absent.

B

Not only are the government’s interests weaker here than in Opperman and Lafayette, but respondent’s privacy interest is greater. In upholding the search in Opperman, the Court emphasized the fact that the defendant had a diminished expectation of privacy in his automobile, due to “pervasive and continuing governmental regulation and controls, including periodic inspection and licensing requirements” and “the obviously public nature of automobile travel.” 428 U. S., at 368. See also id., at 379 (Powell, J., concurring); but see id., at 386-388 (Marshall, J., dissenting). Similarly, in Lafayette, the Court emphasized the *387fact that the defendant was in custody at the time the inventory took place. 462 U. S., at 645-646.

Here the Court completely ignores respondent’s expectation of privacy in his backpack. Whatever his expectation of privacy in his automobile generally, our prior decisions clearly establish that he retained a reasonable expectation of privacy in the backpack and its contents. See Arkansas v. Sanders, 442 U. S. 753, 762 (1979) (“[L]uggage is a common repository for one’s personal effects, and therefore is inevitably associated with the expectation of privacy”); United States v. Chadwick, 433 U. S. 1, 13 (1977) (“[A] person’s expectations of privacy in personal luggage are substantially greater than in an automobile”). Indeed, the Boulder police officer who conducted the inventory acknowledged that backpacks commonly serve as repositories for personal effects.8 Thus, even if the governmental interests in this case were the same as those in Opperman, they would nonetheless be outweighed by respondent’s comparatively greater expectation of privacy in his luggage.

f — i HH I — I

In Coolidge v. New Hampshire, 403 U. S. 443, 461-462 (1971), a plurality of this Court stated: “The word ‘automobile’ is not a talisman in whose presence the Fourth Amendment fades away and disappears.” By upholding the search in this case, the Court not only ignores that principle, but creates another talisman to overcome the requirements of the Fourth Amendment — the term “inventory.” Accordingly, I dissent.

Justice O’Connor

delivered the opinion of the Court.

In Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990), and United States v. Martinez-Fuerte, 428 U. S. 543 (1976), we held that brief, suspicionless seizures at highway checkpoints for the purposes of combating drunk driving and intercepting illegal immigrants were constitutional. We now consider the constitutionality of a highway checkpoint program whose primary purpose is the discovery and interdiction of illegal narcotics.

I

In August 1998, the city of Indianapolis began to operate vehicle checkpoints bn Indianapolis roads in an effort to interdict unlawful drugs. The city conducted six such roadblocks between August and November that year, stopping *351,161 vehicles and arresting 104 motorists. Fifty-five arrests were for drug-related crimes, while 49 were for offenses unrelated to drugs. Edmond v. Goldsmith, 183 F. 3d 659, 661 (CA7 1999). The overall “hit rate” of the program was thus approximately nine percent.

The parties stipulated to the facts concerning the operation of the checkpoints by the Indianapolis Police Department (IPD) for purposes of the preliminary injunction proceedings instituted below. At each checkpoint location, the police stop a predetermined number of vehicles. Approximately 30 officers are stationed at the checkpoint. Pursuant to written directives issued by the chief of police, at least one officer approaches the vehicle, advises the driver that he or she is being stopped briefly at a drug checkpoint, and asks the driver to produce a license and registration. The officer also looks for signs of impairment and conducts an open-view examination of the vehicle from the outside. A narcotics-detection dog walks around the outside of each stopped vehicle.

The directives instruct the officers that they may conduct a search only by consent or based on the appropriate quantum of particularized suspicion. The officers must conduct each stop in the same manner until particularized suspicion develops, and the officers have no discretion to stop any vehicle out of sequence. The city agreed in the stipulation to operate the checkpoints in such a way as to ensure that the total duration of each stop, absent reasonable suspicion or probable cause, would be five minutes or less.

The affidavit of Indianapolis Police Sergeant Marshall DePew, although it is technically outside the parties’ stipulation, provides further insight concerning the operation of the checkpoints. According to Sergeant DePew, checkpoint locations are selected weeks in advance based on such considerations as area crime statistics and traffic flow. The checkpoints are generally operated during daylight hours and are identified with lighted signs reading, “ ‘NARCOTICS *36CHECKPOINT_MILE AHEAD, NARCOTICS K-9 IN USE, BE PREPARED TO STOP.’” App. to Pet. for Cert. 57a. Once a group of cars has been stopped, other traffic proceeds without interruption until all the stopped cars have been processed or diverted for further processing. Sergeant DePew also stated that the average stop for a vehicle not subject to further processing lasts two to three minutes or less.

Respondents James Edmond and Joell Palmer were each stopped at a narcotics checkpoint in late September 1998. Respondents then filed a lawsuit on behalf of themselves and the class of all motorists who had been stopped or were subject to being stopped in the future at the Indianapolis drug checkpoints. Respondents claimed that the roadblocks violated the Fourth Amendment of the United States Constitution and the search and seizure provision of the Indiana Constitution. Respondents requested declaratory and in-junctive relief for the class, as well as damages and attorney’s fees for themselves.

Respondents then moved for a preliminary injunction. Although respondents alleged that the officers who stopped them did not follow the written directives, they agreed to the stipulation concerning the operation of the checkpoints for purposes of the preliminary injunction proceedings. The parties also stipulated to certification of the plaintiff class. The United States District Court for the Southern District ■ of Indiana agreed to class certification and denied the motion for a preliminary injunction, holding that the checkpoint program did not violate the Fourth Amendment. Edmond v. Goldsmith, 38 F. Supp. 2d 1016 (1998). A divided panel of the United States Court of Appeals for the Seventh Circuit reversed, holding that the checkpoints contravened the Fourth Amendment. 183 F. 3d 659 (1999). The panel denied rehearing. We granted certiorari, 528 U. S. 1153 (2000), and now affirm.

*37II

The Fourth Amendment requires that searches and seizures be reasonable. A search or seizure is ordinarily unreasonable in the absence of individualized suspicion of wrongdoing. Chandler v. Miller, 520 U. S. 305, 308 (1997). While such suspicion is not an “irreducible” component of reasonableness, Martinez-Fuerte, 428 U. S., at 561, we have recognized only limited circumstances in which the usual rule does not apply. For example, we have upheld certain regimes of suspicionless searches where the program was designed to serve “special needs, beyond the normal need for law enforcement.” See, e. g., Vernonia School Dist. 47J v. Acton, 515 U. S. 646 (1995) (random drug testing of studentathletes); Treasury Employees v. Von Raab, 489 U. S. 656 (1989) (drug tests for United States Customs Service employees seeking transfer or promotion to certain positions); Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602 (1989) (drug and alcohol tests for railway employees involved in train accidents or found to be in violation of particular safety regulations). We have also allowed searches for certain administrative purposes without particularized suspicion of misconduct, provided that those searches are appropriately limited. See, e. g., New York v. Burger, 482 U. S. 691, 702-704 (1987) (warrantless administrative inspection of premises of “closely regulated” business); Michigan v. Tyler, 436 U. S. 499, 507-509, 511-512 (1978) (administrative inspection of fire-damaged premises to determine cause of blaze); Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523, 534-539 (1967) (administrative inspection to ensure compliance with city housing code).

We have alsoseizures of motorists at a fixed Border Patrol checkpoint designed to intercept illegal aliens, Martinez-Fuerte, supra, and at a sobriety checkpoint aimed at removing drunk drivers from the road, Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990). In addition, in Delaware v. Prouse, 440 U. S. 648, 663 (1979), *38we suggested that a similar type of roadblock with the purpose of verifying drivers’ licenses and vehicle registrations would be permissible. In none of these cases, however, did we indicate approval of a checkpoint program whose primary purpose was to detect evidence of ordinary criminal wrongdoing.

In Martinez-Fuerte, we challenges to stops at two permanent immigration checkpoints located on major United States highways less than 100 miles from the Mexican border. We noted at the outset the particular context in which the constitutional question arose, describing in some detail the “formidable law enforcement problems” posed by the northbound tide of illegal entrants into the United States. 428 U. S., at 551-554. These problems had also been the focus of several earlier cases addressing the constitutionality of other Border Patrol traffic-checking operations. See United States v. Ortiz, 422 U. S. 891 (1975); United States v. Brignoni-Ponce, 422 U. S. 873 (1975); Almeida-Sanchez v. United States, 413 U. S. 266 (1973). In Martinez-Fuerte, we found that the balance tipped in favor of the Government’s interests in policing the Nation’s borders. 428 U. S., at 561-564. In so finding, we emphasized the difficulty of effectively containing illegal immigration at the border itself. Id., at 556. We also stressed the impracticality of the particularized study of a given car to discern whether it was transporting illegal aliens, as well as the relatively modest degree of intrusion entailed by the stops. Id., at 556-564.

Our subsequent cases specifically related to the need to police the border were a significant factor in our Martinez-Fuerte decision. For example, in United States v. Montoya de Hernandez, 473 U. S. 531, 538 (1985), we counted Martinez-Fuerte as one of a number of Fourth Amendment cases that “reflect longstanding concern for the protection of the integrity of the border.” Although the stops in Martinez-Fuerte did not occur at the *39border itself, the checkpoints were located near the border and served a border. control function made necessary by the difficulty of guarding the border’s entire length. See Martinez-Fuerte, supra, at 556.

In Sitz, we evaluated the constitutionality of a Michigan highway sobriety checkpoint program. The Sitz checkpoint involved brief, suspicionless stops of motorists so that police officers could detect signs of intoxication and remove impaired drivers from the road. 496 U. S., at 447-448. Motorists who exhibited signs of intoxication were diverted for a license and registration check and, if warranted, further sobriety tests. Id., at 447. This checkpoint program was clearly aimed at reducing the immediate hazard posed by the presence of drunk drivers on the highways, and there was an obvious connection between the imperative of highway safety and the law enforcement practice at issue. The gravity of the drunk driving problem and the magnitude of the State’s interest in getting drunk drivers off the road weighed heavily in our determination that the program was constitutional. See id., at 451.

In Prouse, we invalidated a discretionary, suspicionless stop for a spot check of a motorist’s driver’s license and vehicle registration. The officer’s conduct' in that case was unconstitutional primarily on account of his exercise of “stand-ardless and unconstrained discretion.” 440 U. S., at 661. We nonetheless acknowledged the States’ “vital interest in ensuring that only those qualified to do so are permitted to operate motor vehicles, that these vehicles are fit for safe operation, and hence that licensing, registration, and vehicle inspection requirements are being observed.” Id., at 658. Accordingly, we suggested that “[questioning of all oncoming traffic at roadblock-type stops” would be a lawful means of serving this interest in highway safety. Id., at 668.

We furtherwe considered the purposes of such a hypothetical roadblock to be distinct from a general purpose of investigating crime. The State prof*40fered the additional interests of “the apprehension of stolen motor vehicles and of drivers under the influence of alcohol or narcotics” in its effort to justify the discretionary spot check. Id,, at 659, n. 18. We attributed the entirety of the latter interest to the State’s interest in roadway safety. Ibid. We also noted that the interest in apprehending stolen vehicles may be partly subsumed by the interest in roadway safety. Ibid. We observed, however, that “[t]he remaining governmental interest in controlling automobile thefts is not distinguishable from the general interest in crime control.” Ibid. Not only does the common thread of highway safety thus run through Sitz and Prouse, but Prouse itself reveals a difference in the Fourth Amendment significance of highway safety interests and the general interest in crime control.

III

It is well established that a vehicle stop at a highway checkpoint effectuates a seizure within the meaning of the Fourth Amendment. See, e. g., Sitz, supra, at 450. The fact that officers walk a narcotics-detection dog around the exterior of each car at the Indianapolis checkpoints does not transform the seizure into a search. See United States v. Place, 462 U. S. 696, 707 (1983). Just as in Place, an exterior sniff of an automobile does not require entry into the car and is not designed to disclose any information other than the presence or absence of narcotics. See ibid. Like the dog sniff in Place, a sniff by a dog that simply walks around a car is “much less intrusive than a typical search.” Ibid. Cf. United States v. Turpin, 920 F. 2d 1377, 1385 (CA8 1990). Rather, what principally distinguishes these checkpoints from those we have previously approved is their primary purpose.

As petitioners gram unquestionably has the primary purpose of interdicting illegal narcotics. In their stipulation of facts, the parties repeatedly refer to the checkpoints as “drug checkpoints” and *41describe them as “being operated by the City of Indianapolis in an effort to interdict unlawful drugs in Indianapolis.” App. to Pet. for Cert. 51a-52a. In addition, the first document attached to the parties’ stipulation is entitled “DRUG CHECKPOINT CONTACT OFFICER DIRECTIVES BY ORDER OF THE CHIEF OF POLICE.” Id., at 53a. These directives instruct officers to “[a]dvise the citizen that they are being stopped briefly at a drug checkpoint.” Ibid. The second document attached to the stipulation is entitled “1998 Drug Road Blocks” and contains a statistical breakdown of information relating to the checkpoints conducted. Id., at 55a. Further, according to Sergeant DePew, the checkpoints are identified with lighted signs reading, “‘NARCOTICS CHECKPOINT _ MILE AHEAD, NARCOTICS K-9 IN USE, BE PREPARED TO STOP.’” Id., at 57a. Finally, both the District Court and the Court of Appeals recognized that the primary purpose of the roadblocks is the interdiction of narcotics. 38 F. Supp. 2d, at 1026 (noting that both parties “stress the primary purpose of the roadblocks as the interdiction of narcotics” and that “[t]he IPD has made it clear that the purpose for its checkpoints is to interdict narcotics traffic”); 183 F. 3d, at 665 (observing that “the City concedes that its proximate goal is to catch drug offenders”).

We have never approved a checkpoint program whose primary purpose was to detect evidence of ordinary criminal wrongdoing. Rather, our checkpoint cases have recognized only limited exceptions to the general rule that a seizure must be accompanied by some measure of individualized suspicion. We suggested in Prouse that we would not credit the “general interest in crime control” as justification for a regime of suspicionless stops. 440 U. S., at 659, n. 18. Consistent with this suggestion, each of the checkpoint programs that we have approved was designed primarily to serve purposes closely related to the problems of policing the border or the necessity of ensuring roadway safety. Because the *42primary purpose of the Indianapolis narcotics checkpoint program is to uncover evidence of ordinary criminal wrongdoing, the program contravenes the Fourth Amendment.

Petitioners propose ways detection purpose of the instant checkpoint program may instead resemble the primary purposes of the checkpoints in Sitz and Martinez-Fuerte. Petitioners state that the checkpoints in those cases had the same ultimate purpose of arresting those suspected of committing crimes. Brief for Petitioners 22. Securing the border and apprehending drunk drivers are, of course, law enforcement activities, and law enforcement officers employ arrests and criminal prosecutions in pursuit of these goals. See Sitz, 496 U. S., at 447, 450; Martinez-Fuerte, 428 U. S., at 545-550. If we were to rest the case at this high level of generality, there would be little check on the ability of the authorities to construct roadblocks for almost any conceivable law enforcement purpose. Without drawing the line at roadblocks designed primarily to serve the general interest in crime control, the Fourth Amendment would do little to prevent such intrusions from becoming a routine part of American life.

Petitioners also emphasize severe ture of the drug problem as justification for the checkpoint program. Brief for Petitioners 14-17, 31. There is no doubt that traffic in illegal narcotics creates social harms of the first magnitude. Cf. Von Raab, 489 U. S., at 668. The law enforcement problems that the drug trade creates likewise remain daunting and complex, particularly in light of the myriad forms of spin-off crime that it spawns. Cf. Montoya de Hernandez, 473 U. S., at 538. The same can be said of various other illegal activities, if only to a lesser degree. But the gravity of the threat alone cannot be dispositive of questions concerning what means law enforcement officers may employ to pursue a given purpose. Rather, in determining whether individualized suspicion is required, we must consider the nature of the interests threatened and their con-*43neetion to the particular law enforcement practices at issue. We are particularly reluctant to recognize exceptions to the general rule of individualized suspicion where governmental authorities primarily pursue their general crime control ends.

Nor can the narcotics-interdiction purpose of the checkpoints be rationalized in terms of a highway safety concern similar to that present in Sitz. The detection and punishment of almost any criminal offense serves broadly the safety of the community, and our streets would no doubt be safer but for the scourge of illegal drugs. Only with respect to a smaller class of offenses, however, is society confronted with the type of immediate, vehicle-bound threat to life and limb that the sobriety checkpoint in Sitz was designed to eliminate.

Petitioners also liken the anticontraband agenda of the Indianapolis checkpoints to the antismuggling purpose of the checkpoints in Martinez-Fuerte. Brief for Petitioners 15-16. Petitioners cite this Court’s conclusion in Martinez-Fuerte that the flow of traffic was too heavy to permit “particularized study of a given car that would enable it to be identified as a possible carrier of illegal aliens,” 428 U. S., at 557, and claim that this logic has even more force here. The problem with this argument is that the same logic prevails any time a vehicle is employed to conceal contraband or other evidence of a crime. This type of connection to the roadway is very different from the close connection to roadway safety that was present in Sitz and Prouse. Further, the Indianapolis checkpoints are far removed from the border context that was crucial in Martinez-Fuerte. While the difficulty of examining each passing car was an important factor in validating the law enforcement technique employed in Martinez-Fuerte, this factor alone cannot justify a regime of suspicionless searches or seizures. Rather, we must look more closely at the nature of the public interests that such a regime is designed principally to serve.

*44The primary purpose of the Indianapolis narcotics checkpoints is in the end to advance “the general interest in crime control,” Prouse, 440 U. S., at 659, n. 18. We decline to suspend the usual requirement of individualized suspicion where the police seek to employ a checkpoint primarily for the ordinary enterprise of investigating crimes. We cannot sanction stops justified only by the generalized and ever-present possibility that interrogation and inspection may reveal that any given motorist has committed some crime.

Of course, are enforcement checkpoint where the primary purpose would otherwise, but for some emergency, relate to ordinary crime control. For example, as the Court of Appeals noted, the Fourth Amendment would almost certainly permit an appropriately tailored roadblock set up to thwart an imminent terrorist attack or to catch a dangerous criminal who is likely to flee by way of a particular route. See 183 F. 3d, at 662-663. The exigencies created by these scenarios are far removed from the circumstances under which authorities might simply stop cars as a matter of course to see if there just happens to be a felon leaving the jurisdiction. While we do not limit the purposes that may justify a checkpoint program to any rigid set of categories, we decline to approve a program whose primary purpose is ultimately indistinguishable from the general interest in crime control.1

*45Petitioners argue that our prior cases preclude an inquiry into the purposes of the checkpoint program. For example, they cite Whren v. United States, 517 U. S. 806 (1996), and Bond v. United States, 529 U. S. 334 (2000), to support the proposition that “where the government articulates and pursues a legitimate interest for a suspicionless stop, courts should not look behind that interest to determine whether the government’s ‘primary purpose’ is valid.” Brief for Petitioners 34; see also id., at 9. These cases, however, do not control the instant situation.

In Whren, we held that an individual officer’s subjective intentions are irrelevant to the Fourth Amendment validity of a traffic stop that is justified objectively by probable cause to believe that a traffic violation has occurred. 517 U. S., at 810-813. We observed that our prior cases “foreclose any argument that the constitutional reasonableness of traffic stops depends on the actual motivations of the individual officers involved.” Id., at 813. In so holding, we expressly distinguished eases where we had addressed the validity of searches conducted in the absence of probable cause. See id., at 811-812 (distinguishing Florida v. Wells, 495 U. S. 1, 4 (1990) (stating that “an inventory search must not be a ruse for a general rummaging in order to discover incriminating evidence”), Colorado v. Bertine, 479 U. S. 367, 372 (1987) (suggesting that the absence of bad faith and the lack of a purely investigative purpose were relevant to the validity of an inventory search), and Burger, 482 U. S., at 716-717, n. 27 (observing that a valid administrative inspection conducted with neither a warrant nor probable cause did not appear to be a pretext for gathering evidence of violations of the penal laws)).

Whren therefore reinforces the principle that, while “[sjubjective intentions play no role in ordinary, probable-cause Fourth Amendment analysis,” 517 U. S., at 813, programmatic purposes may be relevant to the validity of Fourth Amendment intrusions undertaken pursuant to a *46general scheme without individualized suspicion. Accordingly, Whren does not preclude an inquiry into programmatic purpose in such contexts. Cf. Chandler v. Miller, 520 U. S. 305 (1997); Treasury Employees v. Von Raab, 489 U. S. 656 (1989); Burger, supra; Michigan v. Tyler, 436 U. S. 499 (1978); Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523 (1967). It likewise does not preclude an inquiry into programmatic purpose here.

Last we law enforcement officer violated a reasonable expectation of privacy in conducting a tactile examination of carry-on luggage in the overhead compartment of a bus. In doing so, we simply noted that the principle of Whren rendered the subjective intent of an officer irrelevant to this analysis. 529 U. S., at 338, n. 2. While, as petitioners correctly observe, the analytical rubric of Bond was not “ordinary, probable-cause Fourth Amendment analysis,” Whren, supra, at 813, nothing in Bond suggests that we would extend the principle of Whren to all situations where individualized suspicion was lacking. Rather, subjective intent was irrelevant in Bond because the inquiry that our precedents required focused on the objective effects of the actions of an individual officer. By contrast, our cases dealing with intrusions that occur pursuant to a general scheme absent individualized suspicion have often required an inquiry into purpose at the programmatic level.

Petitioners argue that the Indianapolis checkpoint program is justified by its lawful secondary purposes of keeping impaired motorists off the road and verifying licenses and registrations. Brief for Petitioners 31-34. If this were the case, however, law enforcement authorities would be able to establish checkpoints for virtually any purpose so long as they also included a license or sobriety check. For this reason, we examine the available evidence to determine the primary purpose of the checkpoint program. While we recognize the challenges inherent in a purpose inquiry, courts *47routinely engage in this enterprise in many areas of constitutional jurisprudence as a means of sifting abusive governmental conduct from that which is lawful. Cf. 183 F. 3d, at 665. As a result, a program driven by an impermissible purpose may be proscribed while a program impelled by licit purposes is permitted, even though the challenged conduct may be outwardly similar. While reasonableness under the Fourth Amendment is predominantly an objective inquiry, our special needs and administrative search cases demonstrate that purpose is often relevant when suspicionless intrusions pursuant to a general scheme are at issue.2

It goes saying that our holding today does nothing to alter the constitutional status of the sobriety and border checkpoints that we approved in Sitz and Martinez-Fuerte, or of the type of traffic checkpoint that we suggested would be lawful in Prouse. The constitutionality of such checkpoint programs still depends on a balancing of the competing interests at stake and the effectiveness of the program. See Sitz, 496 U. S., at 450-455; Martinez-Fuerte, 428 U. S., at 556-564. When law enforcement authorities pursue primarily general crime control purposes at checkpoints such as here, however, stops can only be justified by some quantum of individualized suspicion.

Our holding also does not affect the validity of border searches or searches at places like airports and government *48buildings, where the need for such measures to ensure public safety can be particularly acute. Nor does our opinion speak to other intrusions aimed primarily at purposes beyond the general interest in crime control. Our holding also does not impair the ability of police officers to act appropriately upon information that they properly learn during a checkpoint stop justified by a lawful primary purpose, even where such action may result in the arrest of a motorist for an offense unrelated to that purpose. Finally, we caution that the purpose inquiry in this context is to be conducted only at the programmatic level and is not an invitation to probe the minds of individual officers acting at the scene. Cf. Whren, supra.

Because the primary purpose point program is ultimately indistinguishable from the general interest in crime control, the checkpoints violate the Fourth Amendment. The judgment of the Court of Appeals is, accordingly, affirmed.

It is so ordered.

ChieF Justice Rehnquist,

with whom Justice Thomas joins, and with whom Justice Scalia joins as to Part I, dissenting.

The State’s use of a drug-sniffing dog, according to the Court’s holding, annuls what is otherwise plainly constitutional under our Fourth Amendment jurisprudence: brief, standardized, discretionless, roadblock seizures of automobiles, seizures which effectively serve a weighty state interest with only minimal intrusion on the privacy of their occupants. Because these seizures serve the State’s accepted and significant interests of preventing drunken driving and checking for driver’s licenses and vehicle registrations, and because there is nothing in the record to indicate that the addition of the dog sniff lengthens these otherwise legitimate seizures, I dissent.

*49I

As it is nowhere to be found m the Court’s opinion, I begin with blackletter roadblock seizure law. “The principal protection of Fourth Amendment rights at checkpoints lies in appropriate limitations on the scope of the stop.” United States v. Martinez-Fuerte, 428 U. S. 543, 566-567 (1976). Roadblock seizures are consistent with the Fourth Amendment if they are “carried out pursuant to a plan embodying explicit, neutral limitations on the conduct of individual officers.” Brown v. Texas, 443 U. S. 47, 51 (1979). Specifically, the constitutionality of a seizure turns upon “a weighing of the gravity of the public concerns served by the seizure, the degree to which the seizure advances the public interest, and the severity of the interference with individual liberty.” Id., at 50-51.

We first applied these principles in Martinez-Fuerte, supra, which approved highway checkpoints for detecting illegal aliens. In Martinez-Fuerte, we balanced the United States’ formidable interest in checking the flow of illegal immigrants against the limited “objective” and “subjective” intrusion on the motorists. The objective intrusion — the stop itself,1 the brief questioning of the occupants, and the visual inspection of the car — was considered “limited” because “[n]either the vehicle nor its occupants [were] searched.” Id., at 558. Likewise, the subjective intrusion, or the fear and surprise engendered in law-abiding motorists by the nature of the stop, was found to be minimal because the “regularized manner in which [the] established checkpoints [were] operated [was] visible evidence, reassuring to law-abiding motorists, that the stops [were] duly authorized and believed to serve the public interest.” Id., at 559. Indeed, the standardized operation of the roadblocks was viewed as *50markedly different from roving patrols, where the unbridled discretion of officers in the field could result in unlimited interference with motorists’ use of the highways. Cf. United States v. Brignoni-Ponce, 422 U. S. 873 (1975). And although the decision in Martinez-Fuerte did not turn on the checkpoints’ effectiveness, the record in one of the consolidated cases demonstrated that illegal aliens were found in 0.12 percent of the stopped vehicles. See 428 U. S., at 554.

In Michigan Dept. of State v. (1990), we upheld the State’s use of a highway sobriety checkpoint after applying the framework set out in Martinez-Fuerte, supra, and Brown v. Texas, supra. There, we recognized the gravity of the State’s interest in curbing drunken driving and found the objective intrusion of the approximately 25-second seizure to be “slight.” 496 U. S., at 451. Turning to the subjective intrusion, we noted that the checkpoint was selected pursuant to guidelines and was operated by uniformed officers. See id., at 453. Finally, we concluded that the program effectively furthered the State’s interest because the checkpoint resulted in the arrest of two drunk drivers, or 1.6 percent of the 126 drivers stopped. See id., at 455-456.

This case follows naturally from Martinez-Fuerte and Sitz. Petitioners acknowledge that the “primary purpose” of these roadblocks is to interdict illegal drugs, but this fact should not be controlling. Even accepting the Court’s conclusion that the checkpoints at issue in Martinez-Fuerte and Sitz were not primarily related to criminal law enforcement,2 the *51question whether a law enforcement purpose could support a roadblock seizure is not presented in this case. The District Court found that another “purpose of the checkpoints is to check driver’s licenses and vehicle registrations,” App. to Pet. for Cert. 44a, and the written directives state that the police officers are to “[l]ook for signs of impairment,” id., at 53a. The use of roadblocks to look for signs of impairment was validated by Sitz, and the use of roadblocks to check for driver’s licenses and vehicle registrations was expressly recognized in Delaware v. Prouse, 440 U. S. 648, 663 (1979).3 That the roadblocks serve these legitimate state interests cannot be seriously disputed, as the 49 people arrested for offenses unrelated to drugs can attest. Edmond v. Goldsmith, 183 F. 3d 659, 661 (CA7 1999). And it would be speculative to conclude — given the District Court’s findings, the written directives, and the actual arrests — that petitioners would not have operated these roadblocks but for the State’s interest in interdicting drugs.

Because of the valid reasons for conducting these roadblock seizures, it is constitutionally irrelevant that petitioners also hoped to interdict drugs. In Whren v. United States, 517 U. S. 806 (1996), we held that an officer’s subjective intent would not invalidate an otherwise objectively justifiable stop of an automobile. The reasonableness of an officer’s discretionary decision to stop an automobile, at issue in Whren, turns on whether there is probable cause to believe that a traffic violation has occurred. The reasonableness of highway checkpoints, at issue here, turns on whether they effectively serve a significant state interest with minimal intrusion on motorists. The stop in Whren was objectively reasonable because the police officers had witnessed traffic violations; so too the roadblocks here are objectively *52reasonable because they serve the substantial interests of preventing drunken driving and checking for driver’s licenses and vehicle registrations with minimal intrusion on motorists.

Once the constitutional requirements for a particular seizure are satisfied, the subjective expectations of those responsible for it, be it police officers or members of a city council, are irrelevant. Cf. Scott v. United States, 436 U. S. 128, 136 (1978) (“Subjective intent alone . . . does not make otherwise lawful conduct illegal or unconstitutional”). It is the objective effect of the State’s actions on the privacy of the individual that animates the Fourth Amendment. See Bond v. United States, 529 U. S. 334, 338, n. 2 (2000) (applying Wkren to determine if an officer’s conduct amounted to a “search” under the Fourth Amendment because “the issue is not his state of mind, but the objective effect of his actions”). Because the objective intrusion of a valid seizure does not turn upon anyone’s subjective thoughts, neither should our constitutional analysis.4

With these checkpoints serving ests, the remaining prongs of the Brown v. Texas balancing test are easily met. The seizure is objectively reasonable as it lasts, on average, two to three minutes and does not involve a search. App. to Pet. for Cert. 57a. The subjective intrusion is likewise limited as the checkpoints are clearly marked and operated by uniformed officers who are directed to stop every vehicle in the same manner. Ibid. The only difference between this case and Sitz is the presence of the dog. We have already held, however, that a “sniff test” by a trained narcotics dog is not a “search” within the meaning of the Fourth Amendment because it does not require physical intrusion of the object being sniffed and it does not ex*53pose anything other than the contraband items. United States v. Place, 462 U. S. 696, 706-707 (1983). And there is nothing in the record to indicate that the dog sniff lengthens the stop. Finally, the checkpoints’ success rate — 49 arrests for offenses unrelated to drugs — only confirms the State’s legitimate interests in preventing drunken driving and ensuring the proper licensing of drivers and registration of their vehicles. 183 F. 3d, at 661.5

These stops effectively serve the State’s legitimate interests; they are executed in a regularized and neutral manner; and they only minimally intrude upon the privacy of the motorists. They should therefore be constitutiorial.

II

The Court, unwilling to adopt the straightforward analysis that these precedents dictate, adds a new non-law-enforcement primary purpose test lifted from a distinct area of Fourth Amendment jurisprudence relating to the searches of homes and businesses. As discussed above, the question that the Court answers is not even posed in this case given the accepted reasons for the seizures. But more fundamentally, whatever sense a non-law-enforcement primary purpose test may make in the search setting, it is ill suited to brief roadblock seizures, where we have consistently looked at “the scope of the stop” in assessing a program’s constitutionality. Martinez-Fuerte, 428 U. S., at 567.

We haan to apply the non-law-enforcement primary purpose test that the Court now finds so indispensable. The respondents in Sitz argued that the Brown v. Texas balancing test was not the “proper method of analysis” with regards to roadblock seizures:

“Respondents argue that there must be a showing of some special governmental need ‘beyond the normal *54need’ for criminal law enforcement before a balancing analysis is appropriate, and that [the State] ha[s] demonstrated no such special need.

“But it is perfectly plain from a Employees v.] Von Raab[, 489 U. S. 656 (1989)], which cited and discussed with approval our earlier decision in United States v. Martinez-Fuerte, 428 U. S. 543 (1976), that it was in no way designed to repudiate our prior cases dealing with police stops of motorists on public highways. Martinez-Fuerte, supra, which utilized a balancing analysis in approving highway checkpoints for detecting illegal aliens, and Brown v. Texas, supra, are the relevant authorities here.” 496 U. S., at 449, 450.

Considerations of stare decisis aside, the “perfectly plain” reason for not incorporating the “special needs” test in our roadblock seizure cases is that seizures of automobiles “deal neither with searches nor with the sanctity of private dwellings, ordinarily afforded the most stringent Fourth Amendment protection.” Martinez-Fuerte, supra, at 561.

The “special hold certain suspicionless searches performed for reasons unrelated to law enforcement, is an exception to the general rule that a search must be based on individualized suspicion of wrongdoing. See, e. g., Skinner v. Railway Labor Executives’ Assn., 489 U. S. 602 (1989) (drug test search); Camara v. Municipal Court of City and County of San Francisco, 887 U. S. 523 (1967) (home administrative search). The doctrine permits intrusions into a person’s body and home, areas afforded the greatest Fourth Amendment protection. But there were no such intrusions here.

“[0]ne’s expectation of privacy in an automobile and of freedom in its operation are significantly different from the traditional expectation of privacy and freedom in one’s residence.” Martinez-Fuerte, supra, at 561. This is because “[a]utomobiles, unlike homes, are subjected to pervasive and continuing governmental regulation and controls.” South *55 Dakota v. Opperman, 428 U. S. 364, 368 (1976); see also New York v. Class, 475 U. S. 106, 113 (1986) (“[Ajutomobiles are justifiably the subject of pervasive regulation by the State”); Cardwell v. Lewis, 417 U. S. 583, 590 (1974) (“One has a lesser expectation of privacy in a motor vehicle because its function is transportation and it seldom serves as one’s residence or as the repository of personal effects”). The lowered expectation of privacy in one’s automobile is coupled with the limited nature of the intrusion: a brief, standardized, nonintru-sive seizure.6 The brief seizure of an automobile can hardly be compared to the intrusive search of the body or the home. Thus, just as the “special needs” inquiry serves to both define and limit the permissible scope of those searches, the Brown v. Texas balancing test serves to define and limit the permissible scope of automobile seizures.

Because limitations upon roadblock seizures, the Court’s newfound non-law-enforcement primary purpose test is both unnecessary to secure Fourth Amendment rights and bound to produce wide-ranging litigation over the “purpose” of any given seizure. Police designing highway roadblocks can never be sure of their validity, since a jury might later determine that a forbidden purpose exists. Roadblock stops identical to the one that we upheld in Sitz 10 years ago, or to the one that we upheld 24 years ago in Martinez-Fuerte, may now be challenged on the grounds that they have some concealed forbidden purpose.

Efforts on highways used by millions of motorists are obviously necessary to our society. The Court’s opinion today casts a shadow over what had been assumed, on the basis of stare decisis, to be a perfectly lawful activity. Conversely, if the Indianapolis police had assigned a different purpose to their activity here, but in no way changed what was done on the ground to individual *56motorists, it might well be valid. See ante, at 47, n. 2. The Court’s non-law-enforcement primary purpose test simply does not serve as a proxy for anything that the Fourth Amendment is, or should be, concerned about in the automobile seizure context.

Petitioners’ program complies with our decisions regarding roadblock seizures of automobiles, and the addition of a dog sniff does not add to the length or the intrusion of the stop. Because such stops are consistent with the Fourth Amendment, I would reverse the decision of the Court of Appeals.

Justice Thomas,

dissenting.

Taken together, our decisions in Michigan Dept. of State Police v. Sitz, 496 U. S. 444 (1990), and United States v. Martinez-Fuerte, 428 U. S. 643 (1976), stand for the proposition that suspicionless roadblock seizures are constitutionally permissible if conducted according to a plan that limits the discretion of the officers conducting the stops. I am not convinced that Sitz and Martinez-Fuerte were correctly decided. Indeed, I rather doubt that the Framers of the Fourth Amendment would have considered “reasonable” a program of indiscriminate stops of individuals not suspected of wrongdoing.

Respondents of Sitz and Martinez-Fuerte, and I am reluctant to consider such a step without the benefit of briefing and argument. For the reasons given by The Chief Justice, I believe that those cases compel upholding the program at issue here. I, therefore, join his opinion.

*368Justice Souter

delivered the opinion of the Court.

The issue here is whether a 13-year-old student’s Fourth Amendment right was violated when she was subjected to a search of her bra and underpants by school officials acting on reasonable suspicion that she had brought forbidden prescription and over-the-counter drugs to school. Because there were no reasons to suspect the drugs presented a danger or were concealed in her underwear, we hold that the search did violate the Constitution, but because there is reason to question the clarity with which the right was established, the official who ordered the unconstitutional search is entitled to qualified immunity from liability.

I

The events immediately prior to the search in question began in 13-year-old Savana Redding’s math class at Safford Middle School one October day in 2003. The assistant principal of the school, Kerry Wilson, came into the room and asked Savana to go to his office. There, he showed her a day planner, unzipped and open flat on his desk, in which there were several knives, lighters, a permanent marker, and a cigarette. Wilson asked Savana whether the planner was hers; she said it was, but that a few days before she had lent it to her Mend, Marissa Glines. Savana stated that none of the items in the planner belonged to her.

Wilson then showed Savana four white prescription-strength ibuprofen 400-mg pills, and one over-the-counter blue naproxen 200-mg pill, all used for pain and inflammation but banned under school rules without advance permission. He asked Savana if she knew anything about the pills. Savana answered that she did not. Wilson then told Savana that he had received a report that she was giving these pills to fellow students; Savana denied it and agreed to let Wilson search her belongings. Helen Romero, an administrative assistant, came into the office, and together with Wilson they searched Savana’s backpack, finding nothing.

*369At that point, Wilson instructed Romero to take Savana to the school nurse’s office to search her clothes for pills. Romero and the nurse, Peggy Sehwallier, asked Savana to remove her jacket, socks, and shoes, leaving her in stretch pants and a T-shirt (both without pockets), which she was then asked to remove. Finally, Savana was told to pull her bra out and to the side and shake it, and to pull out the elastic on her underpants, thus exposing her breasts and pelvic area to some degree. No pills were found.

Savana’s mother filed suit against Safford Unified School District #1, Wilson, Romero, and Sehwallier for conducting a strip search in violation of Savana’s Fourth Amendment rights. The individuals (hereinafter petitioners) moved for summary judgment, raising a defense of qualified immunity. The District Court for the District of Arizona granted the motion on the ground that there was no Fourth Amendment violation, and a panel of the Ninth Circuit affirmed. 504 F. 3d 828 (2007).

A closely divided Circuit sitting en bane, however, reversed. Following the two-step protocol for evaluating claims of qualified immunity, see Saucier v. Katz, 533 U. S. 194, 200 (2001), the Ninth Circuit held that the strip search was unjustified under the Fourth Amendment test for searches of children by school officials set out in New Jersey v. T. L. O., 469 U. S. 325 (1985). 531 F. 3d 1071, 1081-1087 (2008). The Circuit then applied the test for qualified immunity, and found that Savana’s right was clearly established at the time of the search: “ '[tjhese notions of personal privacy are “clearly established” in that they inhere in all of us, particularly middle school teenagers, and are inherent in the privacy component of the Fourth Amendment’s proscription against unreasonable searches.’” Id., at 1088-1089 (quoting Brannum v. Overton Cty. School Bd., 516 F. 3d 489, 499 (CA6 2008)). The upshot was reversal of summary judgment as to Wilson, while affirming the judgments in favor of Sehwallier, the school nurse, and Romero, the administrative *370assistant, since they had not acted as independent decision-makers. 531 F. 3d, at 1089.

We granted certiorari, 555 U. S. 1130 (2009), and now affirm in part, reverse in part, and remand.

II

The Fourth Amendment “right of the people to be secure in their persons . . . against unreasonable searches and seizures” generally requires a law enforcement officer to have probable cause for conducting a search. “Probable cause exists where ‘the facts and circumstances within [an officer’s] knowledge and of which [he] had reasonably trustworthy information [are] sufficient in themselves to warrant a man of reasonable caution in the belief that’ an offense has been or is being committed,” Brinegar v. United States, 338 U. S. 160, 175-176 (1949) (quoting Carroll v. United States, 267 U. S. 132, 162 (1925)), and that evidence bearing on that offense will be found in the place to be searched.

In T. L. O., we recognized that the school setting “requires some modification of the level of suspicion of illicit activity needed to justify a search,” 469 U. S., at 340, and held that for searches by school officials “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,” id., at 341. We have thus applied a standard of reasonable suspicion to determine the legality of a school administrator’s search of a student, id., at 342, 345, and have held that a school 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,” id., at 342.

A number of our cases on probable cause have an implicit bearing on the reliable knowledge element of reasonable suspicion, as we have attempted to flesh out the knowledge com*371ponent by looking to the degree to which known facts imply prohibited conduct, see, e. g., Adams v. Williams, 407 U. S. 143, 148 (1972); id., at 160, n. 9 (Marshall, J., dissenting), the specificity of the information received, see, e. g., Spinelli v. United States, 393 U. S. 410, 416-417 (1969), and the reliability of its source, see, e. g., Aguilar v. Texas, 378 U. S. 108, 114 (1964). At the end of the day, however, we have realized that these factors cannot rigidly control, Illinois v. Gates, 462 U. S. 213, 230 (1983), and we have come back to saying that the standards are “fluid concepts that take their substantive content from the particular contexts” in which they are being assessed, Ornelas v. United States, 517 U. S. 690, 696 (1996).

Perhaps the best that can be said generally about the required knowledge component of probable cause for a law enforcement officer’s evidence search is that it raise a “fair probability,” Gates, 462 U. S., at 238, or a “substantial chance,” id., at 244, n. 13, of discovering evidence of criminal activity. The lesser standard for school searches could as readily be described as a moderate chance of finding evidence of wrongdoing.

Ill

A

In this case, the school’s policies strictly prohibit the non-medical use, possession, or sale of any drug on school grounds, including “‘[a]ny prescription or over-the-counter drug, except those for which permission to use in school has been granted pursuant to Board policy.’ ” App. to Pet. for Cert. 128a.1 A week before Savana was searched, another *372student, Jordan Romero (no relation of the school’s administrative assistant), told the principal and Assistant Principal Wilson that “certain students were bringing drugs and weapons on campus,” and that he had been sick after taking some pills that “he got from a classmate.” App. 8a. On the morning of October 8, the same boy handed Wilson a white pill that he said Marissa Glines had given him. He told Wilson that students were planning to take the pills at lunch.

Wilson learned from Peggy Schwallier, the school nurse, that the pill was ibuprofen 400 mg, available only by prescription. Wilson then called Marissa out of class. Outside the classroom, Marissa’s teacher handed Wilson the day planner, found within Marissa’s reach, containing various contraband items. Wilson escorted Marissa back to his office.

In the presence of Helen Romero, Wilson requested Marissa to turn out her pockets and open her wallet. Marissa produced a blue pill, several white ones, and a razor blade. Wilson asked where the blue pill came from, and Marissa answered, “ ‘I guess it slipped in when she gave me the IBU 400s.’” Id., at 13a. When Wilson asked whom she meant, Marissa replied, “‘Savana Redding.’” Ibid. Wilson then enquired about the day planner and its contents; Marissa denied knowing anything about them. Wilson did not ask Marissa any followup questions to determine whether there was any likelihood that Savana presently had pills: neither asking when Marissa received the pills from Savana nor where Savana might be hiding them.

*373Sehwallier did not immediately recognize the blue pill, but information provided through a poison control hotline2 indicated that the pill was a 200-mg dose of an antiinflammatory drug, generically called naproxen, available over the counter. At Wilson’s direction, Marissa was then subjected to a search of her bra and underpants by Romero and Sehwallier, as Savana was later on. The search revealed no additional pills.

It was at this juncture that Wilson called Savana into his office and showed her the day planner. Their conversation established that Savana and Marissa were on friendly terms: while she denied knowledge of the contraband, Savana admitted that the day planner was hers and that she had lent it to Marissa. Wilson had other reports of their friendship from staff members, who had identified Savana and Marissa as part of an unusually rowdy group at the school’s opening dance in August, during which alcohol and cigarettes were found in the girls’ bathroom. Wilson had reason to connect the girls with this contraband, for Wilson knew that Jordan Romero had told the principal that before the dance, he had been at a party at Savana’s house where alcohol was served. Marissa’s statement that the pills came from Savana was thus sufficiently plausible to warrant suspicion that Savana was involved in pill distribution.

This suspicion of Wilson’s was enough to justify a search of Savana’s backpack and outer clothing.3 If a student is *374reasonably suspected of giving out contraband pills, she is reasonably suspected of carrying them on her person and in the carryall that has become an item of student uniform in most places today. If Wilson’s reasonable suspicion of pill distribution were not understood to support searches of outer clothes and backpack, it would not justify any search worth making. And the look into Savana’s bag, in her presence and in the relative privacy of Wilson’s office, was not excessively intrusive, any more than Romero’s subsequent search of her outer clothing.

B

Here it is that the parties part company, with Savana’s claim that extending the search at Wilson’s behest to the point of making her pull out her underwear was constitutionally unreasonable. The exact label for this final step in the intrusion is not important, though strip search is a fair way to speak of it. Romero and Schwallier directed Savana to remove her clothes down to her underwear, and then “pull out” her bra and the elastic band on her underpants. Id., at 23a. Although Romero and Schwallier stated that they did not see anything when Savana followed their instructions, App. to Pet. for Cert. 135a, we would not define strip search and its Fourth Amendment consequences in a way that would guarantee litigation about who was looking and how much was seen. The very fact of Savana’s pulling her underwear away from her body in the presence of the two officials who were able to see her necessarily exposed her breasts and pelvic area to some degree, and both subjective and reasonable societal expectations of personal privacy support the treatment of such a search as categorically distinct, requiring distinct elements of justification on the part of school authorities for going beyond a search of outer clothing and belongings.

Savana’s subjective expectation of privacy against such a search is inherent in her account of it as embarrassing, *375frightening, and humiliating. The reasonableness of her expectation (required by the Fourth Amendment standard) is indicated by the consistent experiences of other young people similarly searched, whose adolescent vulnerability intensifies the patent intrusiveness of the exposure. See Brief for National Association of Social Workers et al. as Amici Curiae 6-14; Hyman & Perone, The Other Side of School Violence: Educator Policies and Practices that may Contribute to Student Misbehavior, 36 J. School Psychology 7, 13 (1998) (strip search can “result in serious emotional damage”). The common reaction of these adolescents simply registers the obviously different meaning of a search exposing the body from the experience of nakedness or near undress in other school circumstances. Changing for gym is getting ready for play; exposing for a search is responding to an accusation reserved for suspected wrongdoers and fairly understood as so degrading that a number of communities have decided that strip searches in schools are never reasonable and have banned them no matter what the facts may be, see, e.g., New York City Dept. of Education, Reg. No. A-432, p. 2 (2005), online at http://docs.nycenet.edu/docushare/dsweb/Get/Document-21/A-432.pdf (“Under no circumstances shall a strip-search of a student be conducted”).

The indignity of the search does not, of course, outlaw it, but it does implicate the rule of reasonableness as stated in T. L. O., that “the search as actually conducted [be] reasonably related in scope to the circumstances which justified the interference in the first place.” 469 U. S., at 341 (internal quotation marks omitted). The scope will be permissible, that is, when it is “not excessively intrusive in light of the age and sex of the student and the nature of the infraction.” Id., at 342.

Here, the content of the suspicion failed to match the degree of intrusion. Wilson knew beforehand that the pills were prescription-strength ibuprofen and over-the-counter naproxen, common pain relievers equivalent to two Advil, or *376one Aleve.4 He must have been aware of the nature and limited threat of the specific drugs he was searching for, and while just about anything can be taken in quantities that will do real harm, Wilson had no reason to suspect that large amounts of the drugs were being passed around, or that individual students were receiving great numbers of pills.

Nor could Wilson have suspected that Savana was hiding common painkillers in her underwear. Petitioners suggest, as a truth universally acknowledged, that “students ... hid[e] contraband in or under their clothing,” Reply Brief for Petitioners 8, and cite a smattering of eases of students with contraband in their underwear, id., at 8-9. But when the categorically extreme intrusiveness of a search down to the body of an adolescent requires some justification in suspected facts, general background possibilities fall short; a reasonable search that extensive calls for suspicion that it will pay off. But nondangerous school contraband does not raise the specter of stashes in intimate places, and there is no evidence in the record of any general practice among Safford Middle School students of hiding that sort of thing in underwear; neither Jordan nor Marissa suggested to Wilson that Savana was doing that, and the preceding search of Marissa that Wilson ordered yielded nothing. Wilson never even determined when Marissa had received the pills from Savana; if it had been a few days before, that would weigh heavily against any reasonable conclusion that Savana presently had the pills on her person, much less in her underwear.

In sum, what was missing from the suspected facts that pointed to Savana was any indication of danger to the students from the power of the drugs or their quantity, and any reason to suppose that Savana was carrying pills in her *377underwear. We think that the combination of these deficiencies was fatal to finding the search reasonable.

In so holding, we mean to cast no ill reflection on the assistant principal, for the record raises no doubt that his motive throughout was to eliminate drugs from his school and protect students from what Jordan Romero had gone through. Parents are known to overreact to protect their children from danger, and a school official with responsibility for safety may tend to do the same. The difference is that the Fourth Amendment places limits on the official, even with the high degree of deference that courts must pay to the educator’s professional judgment.

We do mean, though, to make it clear that the T L. O. concern to limit a school search to reasonable scope requires the support of reasonable suspicion of danger or of resort to underwear for hiding evidence of wrongdoing before a search can reasonably make the quantum leap from outer clothes and backpacks to exposure of intimate parts. The meaning of such a search, and the degradation its subject may reasonably feel, place a search that intrusive in a category of its own demanding its own specific suspicions.

IV

A school official searching a student is “entitled to qualified immunity where clearly established law does not show that the search violated the Fourth Amendment.” Pearson v. Callahan, 555 U. S. 223, 243-244 (2009). To be established clearly, however, there is no need that “the very action in question [have] previously been held unlawful.” Wilson v. Layne, 526 U. S. 603, 615 (1999). The unconstitutionality of outrageous conduct obviously will be unconstitutional, this being the reason, as Judge Posner has said, that “[t]he easiest cases don’t even arise.” K. H. v. Morgan, 914 F. 2d 846, 851 (CA7 1990). But even as to action less than an outrage, “officials can still be on notice that their conduct violates es*378tablished law ... in novel factual circumstances.” Hope v. Pelzer, 536 U. S. 730, 741 (2002).

T. L. O. directed school officials to limit the intrusiveness of a search, “in light of the age and sex of the student and the nature of the infraction,” 469 U. S., at 342, and as we have just said at some length, the intrusiveness of the strip search here cannot be seen as justifiably related to the circumstances. But we realize that the lower courts have reached divergent conclusions regarding how the T L. O. standard applies to such searches.

A number of judges have read T L. O. as the en banc minority of the Ninth Circuit did here. The Sixth Circuit upheld a strip search of a high school student for a drug, without any suspicion that drugs were hidden next to her body. Williams v. Ellington, 936 F. 2d 881, 882-883, 887 (1991). And other courts considering qualified immunity for strip searches have read T. L. O. as “a series of abstractions, on the one hand, and a declaration of seeming deference to the judgments of school officials, on the other,” Jenkins v. Talladega City Bd. of Ed., 115 F. 3d 821, 828 (CA11 1997) (en banc), which made it impossible “to establish clearly the contours of a Fourth Amendment right... [in] the wide variety of possible school settings different from those involved in T. L. O.” itself, ibid. See also Thomas v. Roberts, 323 F. 3d 950 (CA11 2003) (granting qualified immunity to a teacher and police officer who conducted a group strip search of a fifth grade class when looking for a missing $26).

We think these differences of opinion from our own are substantial enough to require immunity for the school officials in this case. We would not suggest that entitlement to qualified immunity is the guaranteed product of disuniform views of the law in the other federal, or state, courts, and the fact that a single judge, or even a group of judges, disagrees about the contours of a right does not automatically render the law unclear if we have been clear. That said, however, the cases viewing school strip searches differently *379from the way we see them are numerous enough, with well-reasoned majority and dissenting opinions, to counsel doubt that we were sufficiently clear in the prior statement of law. We conclude that qualified immunity is warranted.

V

The strip search of Savana Redding was unreasonable and a violation of the Fourth Amendment, but petitioners Wilson, Romero, and Schwallier are nevertheless protected from liability through qualified immunity. Our conclusions here do not resolve, however, the question of the liability of petitioner Safford Unified School District #1 under Monell v. New York City Dept. of Social Servs., 436 U. S. 658, 694 (1978), a claim the Ninth Circuit did not address. The judgment of the Ninth Circuit is therefore affirmed in part and reversed in part, and this case .is remanded for consideration of the Monell claim.

It is so ordered.

Justice Stevens,

with whom Justice Ginsbueg joins, concurring in part and dissenting in part.

In New Jersey v. T. L. O., 469 U. S. 325 (1985), the Court established a two-step inquiry for determining the reasonableness of a school official’s decision to search a student. First, the Court explained, the search must be “ ‘justified at its inception’ ” by the presence of “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.” Id., at 342. Second, the search must be “permissible in its scope,” which is achieved “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.” Ibid. (emphasis added).

Nothing the Court decides today alters this basic framework. It simply applies T. L. O. to declare unconstitutional *380a strip search of a 13-year-old honors student that was based on a groundless suspicion that she might be hiding medicine in her underwear. This is, in essence, a case in which clearly established law meets clearly outrageous conduct. I have long believed that “ ‘[i]t does not require a constitutional scholar to conclude that a nude search of a 13-year-old child is an invasion of constitutional rights of some magnitude.’” Id., at 382, n. 25 (opinion concurring in part and dissenting in part) (quoting Doe v. Renfrow, 631 F. 2d 91, 92-93 (CA7 1980)). The strip search of Savana Redding in this case was both more intrusive and less justified than the search of the student’s purse in T. L. O. Therefore, while I join Parts I — III of the Court’s opinion, I disagree with its decision to extend qualified immunity to the school official who authorized this unconstitutional search.

The Court reaches a contrary conclusion about qualified immunity based on the fact that various Courts of Appeals have adopted seemingly divergent views about T L. O.’s application to strip searches. Ante, at 377-378. But the clarity of a well-established right should not depend on whether jurists have misread our precedents. And while our cases have previously noted the “divergence of views” among courts in deciding whether to extend qualified immunity, e. g., Pearson v. Callahan, 555 U. S. 223, 245 (2009) (noting the unsettled constitutionality of the so-called “eonsentonce-removed” doctrine); Wilson v. Layne, 526 U. S. 603, 618 (1999) (considering conflicting views on the constitutionality of law enforcement’s practice of allowing the media to enter a private home to observe and film attempted arrests), we have relied on that consideration only to spare officials from having “‘to predict the future course of constitutional law,’” id., at 617 (quoting Procunier v. Navarette, 434 U. S. 555, 562 (1978); emphasis added). In this case, by contrast, we chart no new constitutional path. We merely decide whether the decision to strip search Savana Redding, on these facts, was *381prohibited under T L. O. Our conclusion leaves the boundaries of the law undisturbed.*

The Court of Appeals properly rejected the school official’s qualified immunity defense, and I would affirm that court’s judgment in its entirety.

Justice Ginsburg,

concurring in part and dissenting in part.

I agree with the Court that Assistant Principal Wilson’s subjection of 13-year-old Savana Redding to a humiliating stripdown search violated the Fourth Amendment. But I also agree with Justice Stevens, ante, at 379-380 and this page (opinion concurring in part and dissenting in part), that our opinion in New Jersey v. T. L. O., 469 U. S. 325 (1985), “clearly established” the law governing this ease.

Fellow student Marissa Glines, caught with pills in her pocket, accused Redding of supplying them. App. 13a. Asked where the blue pill among several white pills in Glines’s pocket came from, Glines answered: “I guess it slipped in when she gave me the IBU 400s.” Ibid. Asked next “who is sheV’, Glines responded: “Savana Redding.” Ibid. As the Court observes, ante, at 372, 376, no followup questions were asked. Wilson did not test Glines’s accusation for veracity by asking Glines when did Redding give her the pills, where, for what purpose. Any reasonable search for the pills would have ended when inspection of Redding’s backpack and jacket pockets yielded nothing. Wilson had no cause to suspect, based on prior experience at the school or clues in this case, that Redding had hidden pills — containing the equivalent of two Advils or one Aleve — in her underwear or body. To make matters worse, Wilson did not release Redding, to return to class or to go home, after the *382search. Instead, he made her sit on a chair outside his office for over two hours. At no point did he attempt to call her parent. Abuse of authority of that order should not be shielded by official immunity.

In contrast to T. L. O., where a teacher discovered a student smoking in the lavatory, and where the search was confined to the student’s purse, the search of Redding involved her body and rested on the bare accusation of another student whose reliability the Assistant Principal had no reason to trust. The Court’s opinion in T. L. O. plainly stated the controlling Fourth Amendment law: A search ordered by a school official, even if “justified at its inception,” crosses the constitutional boundary if it becomes “excessively intrusive in light of the age and sex of the student and the nature of the infraction.” 469 U. S., at 342 (internal quotation marks omitted).

Here, “the nature of the [supposed] infraction,” the slim basis for suspecting Savana Redding, and her “age and sex,” ibid., establish beyond doubt that Assistant Principal Wilson’s order cannot be reconciled with this Court’s opinion in T. L. O. Wilson’s treatment of Redding was abusive, and it was not reasonable for him to believe that the law permitted it. I join Justice Stevens in dissenting from the Court’s acceptance of Wilson’s qualified immunity plea, and would affirm the Court of Appeals’ judgment in all respects.

Justice Thomas,

concurring in the judgment in part and dissenting in part.

I agree with the Court that the judgment against the school officials with respect to qualified immunity should be reversed. See ante, at 377-379. Unlike the majority, however, I would hold that the search of Savana Redding did not violate the Fourth Amendment. The majority imposes a vague and amorphous standard on school administrators. It also grants judges sweeping authority to second-guess the measures that these officials take to maintain discipline in *383their schools and ensure the health and safety of the students in their charge. This deep intrusion into the administration of public schools exemplifies why the Court should return to the common-law doctrine of in loco parentis under which “the judiciary was reluctant to interfere in the routine business of school administration, allowing schools and teachers to set and enforce rules and to maintain order.” Morse v. Frederick, 551 U. S. 393, 414 (2007) (Thomas, J., concurring). But even under the prevailing Fourth Amendment test established by New Jersey v. T. L. O., 469 U. S. 325 (1985), all petitioners, including the school district, are entitled to judgment as a matter of law in their favor.

I

“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.” Id., at 337. Thus, although public school students retain Fourth Amendment rights under this Court’s precedent, see id., at 333-337, those rights “are different . . . than elsewhere; the ‘reasonableness’ inquiry cannot disregard the schools’ custodial and tutelary responsibility for children,” Vernonia School Disk 47J v. Acton, 515 U. S. 646, 656 (1995); see also T. L. O., 469 U. S., at 339 (identifying “the substantial interest of teachers and administrators in maintaining discipline in the classroom and on school grounds”). For nearly 25 years this Court has understood that “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.” Ibid. In schools, “[e]vents calling for discipline are frequent occurrences and sometimes require immediate, effective action.” Goss v. Lopez, 419 U. S. 565, 580 (1975); see also T. L. O., 469 U. S., at 340 (explaining that schools have a “legitimate need *384to maintain an environment in which learning can take place”).

For this reason, school officials retain broad authority to protect students and preserve “order and a proper educational environment” under the Fourth Amendment. Id., at 339. This authority requires that school officials be able to engage in the “close supervision of schoolchildren, as well as . . . enforc[e] rules against conduct that would be perfectly permissible if undertaken by an adult.” Ibid. Seeking to reconcile the Fourth Amendment with this unique public school setting, the Court in T. L. O. held that a school search is “reasonable” if it is “ ‘justified at its inception’ ” and “ ‘reasonably related in scope to the circumstances which justified the interference in the first place.’ ” Id., at 341-342 (quoting Terry v. Ohio, 392 U. S. 1, 20 (1968)). The search under review easily meets this standard.

A

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.” T. L. O., supra, at 341-342 (footnote omitted). As the majority rightly concedes, this search was justified at its inception because there were reasonable grounds to suspect that Redding possessed medication that violated school rules. See ante, at 373. A finding of reasonable suspicion “does not deal with hard certainties, but with probabilities.” United States v. Cortez, 449 U. S. 411, 418 (1981); see also T. L. O., supra, at 346 (“[T]he requirement of reasonable suspicion is not a requirement of absolute certainty”). To satisfy this standard, more than a mere “hunch” of wrongdoing is required, but “considerably” less suspicion is needed than would be required to “satisf[y] a preponderance of the evidence standard.” United States v. *385 Arvizu, 534 U. S. 266, 274 (2002) (internal quotation marks omitted).

Furthermore, in evaluating whether there is a reasonable “particularized and objective” basis for conducting a search based on suspected wrongdoing, government officials must consider the “totality of the circumstances.” Id., at 273 (internal quotation marks omitted). School officials have a specialized understanding of the school environment, the habits of the students, and the concerns of the community, which enables them to “ ‘formulat[e] certain common-sense conclusions about human behavior.’” United States v. Sokolow, 490 U. S. 1, 8 (1989) (quoting Cortez, supra, at 418). And like police officers, school officials are “entitled to make an assessment of the situation in light of [this] specialized training and familiarity with the customs of the [school].” See Arvizu, supra, at 276.

Here, petitioners had reasonable grounds to suspect that Redding was in possession of prescription and nonprescription drugs in violation of the school’s prohibition of the “non-medical use, possession, or sale of a drug” on school property or at school events. 531 F. 3d 1071, 1076 (CA9 2008) (en banc); see also id., at 1107 (Hawkins, J., dissenting) (explaining that the school policy defined “drugs” to include “ ‘[a]ny prescription or over-the-counter drug, except those for which permission to use in school has been granted’ ”). As an initial matter, school officials were aware that a few years earlier, a student had become “seriously ill” and “spent several days in intensive care” after ingesting prescription medication obtained from a classmate. App. 10a. Fourth Amendment searches do not occur in a vacuum; rather, context must inform the judicial inquiry. See Cortez, supra, at 417-418. In this instance, the suspicion of drug possession arose at a middle school that had “a history of problems with students using and distributing prohibited and illegal substances on campus.” App. 7a, 10a.

*386The school’s substance-abuse problems had not abated by the 2003-2004 school year, which is when the challenged search of Redding took place. School officials had found alcohol and cigarettes in the girls’ bathroom during the first school dance of the year and noticed that a group of students including Redding and Marissa Glines smelled of alcohol. Ibid. Several weeks later, another student, Jordan Romero, reported that Redding had hosted a party before the dance where she served whiskey, vodka, and tequila. Id., at 8a, 11a. Romero had provided this report to school officials as a result of a meeting his mother scheduled with the officials after Romero “bec[a]me violent” and “sick to his stomach” one night and admitted that “he had taken some pills that he had got[ten] from a classmate.” Id., at 7a-8a, 10a-lla. At that meeting, Romero admitted that “certain students were bringing drugs and weapons on campus.” Id., at 8a, 11a. One week later, Romero handed the assistant principal a white pill that he said he had received from Glines. Id., at 11a. He reported “that a group of students [were] planning on taking the pills at lunch.” Ibid.

School officials justifiably took quick action in light of the lunchtime deadline. The assistant principal took the pill to the school nurse who identified it as prescription-strength 400-mg ibuprofen. Id., at 12a. A subsequent search of Glines and her belongings produced a razor blade, a naproxen 200-mg pill, and several ibuprofen 400-mg pills. Id., at 13a. When asked, Glines claimed that she had received the pills from Redding. Ibid. A search of Redding’s planner, which Glines had borrowed, then uncovered “several knives, several lighters, a cigarette, and a permanent marker.” Id., at 12a, 14a, 22a. Thus, as the majority acknowledges, ante, at 373-374, the totality of relevant circumstances justified a search of Redding for pills.1

*387B

The remaining question is whether the search was reasonable in scope. Under T L. 0., “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.” 469 U. S., at 842. The majority concludes that the school officials’ search of Redding’s underwear was not “‘reasonably related in scope to the circumstances which justified the interference in the first place,’” see ante, at 374-377, notwithstanding the officials’ reasonable suspicion that Redding “was involved in pill distribution,” ante, at 373. According to the majority, to be reasonable, this school search required a showing of “danger to the students from the power of the drugs or their quantity” or a “reason to suppose that [Redding] was carrying pills in her underwear.” Ante, at 376-377. Each of these additional requirements is an unjustifiable departure from bedrock Fourth Amendment law in the school setting, where this Court has heretofore read the Fourth Amendment to grant considerable leeway to school officials. Because the school officials searched in a location where the pills could have been hidden, the search was reasonable in scope under T. L. O.

1

The majority finds that “subjective and reasonable societal expectations of personal privacy support... treating]” this type of search, which it labels a “strip search,” as “categorically distinct, requiring distinct elements of justification on the part of school authorities for going beyond a search of *388outer clothing and belongings.” Ante, at 374.2 Thus, in the majority’s view, although the school officials had reasonable suspicion to believe that Redding had the pills on her person, see ante, at 373-374, they needed some greater level of particularized suspicion to conduct this “strip search.” There is no support for this contortion of the Fourth Amendment.

The Court has generally held that the reasonableness of a search’s scope depends only on whether it is limited to the area that is capable of concealing the object of the search. See, e. g., Wyoming v. Houghton, 526 U. S. 295, 307 (1999) (Police officers “may inspect passengers’ belongings found in the car that aré capable of concealing the object of the search”); Florida v. Jimeno, 500 U. S. 248, 251 (1991) (“The scope of a search is generally defined by its expressed object”); United States v. Johns, 469 U. S. 478, 487 (1985) (search reasonable because “there is no plausible argument that the object of the search could not have been concealed in the packages”); United States v. Ross, 456 U. S. 798, 820 (1982) (“A lawful search . . . generally extends to the entire area in which the object of the search may be found”).3

In keeping with this longstanding rule, the “nature of the infraction” referenced in T. L. O. delineates the proper scope of a search of students in a way that is identical to that per*389mitted for searches outside the school — i. e., the search must be limited to the areas where the object of that infraction could be concealed. See Horton v. California, 496 U. S. 128, 141 (1990) (“Police with a warrant for a rifle may search only places where rifles might be” (internal quotation marks omitted)); Ross, supra, at 824 (“[Pjrobable cause to believe that undocumented aliens are being transported in a van will not justify a warrantless search of a suitcase”). A search of a student therefore is permissible in scope under T L. O. so long as it is objectively reasonable to believe that the area searched could conceal the contraband. The dissenting opinion below correctly captured this Fourth Amendment standard, noting that “if a student were rumored to have brought a baseball bat on campus in violation of school policy, a search of that student’s shirt pocket would be patently unjustified.” 531 F. 3d, at 1104 (opinion of Hawkins, J.).

The analysis of whether the scope of the search here was permissible under that standard is straightforward. Indeed, the majority does not dispute that “general background possibilities” establish that students conceal “contraband in their underwear.” Ante, at 376. It acknowledges that school officials had reasonable suspicion to look in Red-ding’s backpack and outer clothing because if “Wilson’s reasonable suspicion of pill distribution were not understood to support searches of outer clothes and backpack, it would not justify any search worth making.” Ante, at 374. The majority nevertheless concludes that proceeding any further with the search was unreasonable. See ante, at 374-377; see also ante, at 381 (Ginsburg, J., concurring in part and dissenting in part) (“Any reasonable search for the pills would have ended when inspection of Redding’s backpack and jacket pockets yielded nothing”). But there is no support for this conclusion. The reasonable suspicion that Redding possessed the pills for distribution purposes did not dissipate simply because the search of her backpack turned up nothing. It was eminently reasonable to conclude that the back*390pack was empty because Redding was secreting the pills in a place she thought no one would look. See Ross, supra, at 820 (“Contraband goods rarely are strewn” about in plain view; “by their very nature such goods must be withheld from public view”).

Redding would not have been the first person to conceal pills in her undergarments. See Hicks, Man Gets 17-Year Drug Sentence, Times-Tribune (Corbin, Ky.), Oct. 7, 2008, pp. 1, 5 (Drug courier “told officials she had the [OxyContin] pills concealed in her crotch”); Conley, Whitehaven: Traffic Stop Yields Hydrocodone Pills, Commercial Appeal (Memphis, Tenn.), Aug. 3, 2007, p. B3 (“An additional 40 hydrocodone pills were found in her pants”); Caywood, Police Vehicle Chase Leads to Drug Arrests, Telegram & Gazette (Worcester, Mass.), June 7, 2008, p. A7 (25-year-old “allegedly had a cigar tube stuffed with pills tucked into the waistband of his pants”); Hubartt, 23-Year-Old Charged With Dealing Ecstasy, Journal Gazette (Fort Wayne, Ind.), Aug. 8,2007, p. 2C (“[W]hile he was being put into a squad car, his pants fell down and a plastic bag containing pink and orange pills fell on the ground”); Sebastian Residents Arrested in Drug Sting, Vero Beach Press Journal, Sept. 16, 2006, p. B2 (Arrestee “told them he had more pills ‘down my pants’ ”). Nor will she be the last after today’s decision, which announces the safest place to secrete contraband in school.

2

The majority compounds its error by reading the “nature of the infraction” aspect of the T. L. O. test as a license to limit searches based on a judge’s assessment of a particular school policy. According to the majority, the scope of the search was impermissible because the school official “must have been aware of the nature and limited threat of the specific drugs he was searching for” and because he “had no reason to suspect that large amounts of the drugs were being passed around, or that individual students were receiving *391great numbers of pills.” Ante, at 376. Thus, in order to locate a rationale for finding a Fourth Amendment violation in this case, the majority retreats from its observation that the school’s firm no-drug policy “makes sense, and there is no basis to claim that the search was unreasonable owing to some defect or shortcoming of the rule it was aimed at enforcing.” Ante, at 372, n. 1.

Even accepting the majority’s assurances that it is not attacking the rule’s reasonableness, it certainly is attacking the rule’s importance. This approach directly conflicts with T. L. O. in which the Court was “unwilling to adopt a standard under which the legality of a search is dependent upon a judge’s evaluation of the relative importance of various school rules.” 469 U. S., at 342, n. 9. Indeed, the Court in T. L. O. expressly rejected the proposition that the majority seemingly endorses — that “some rules regarding student conduct are by nature too ‘trivial’ to justify a search based upon reasonable suspicion.” Ibid.; see also id., at 343, n. 9 (“The promulgation of a rule forbidding specified conduct presumably reflects a judgment on the part of school officials that such conduct is destructive of school order or of a proper educational environment. Absent any suggestion that the rule violates some substantive constitutional guarantee, the courts should, as a general matter, defer to that judgment”).

The majority’s decision in this regard also departs from another basic principle of the Fourth Amendment: that law enforcement officials can enforce with the same vigor all rules and regulations irrespective of the perceived importance of any of those rules. “In a long line of cases, we have said that when an officer has probable cause to believe a person committed even a. minor crime in his presence, the balancing of private and public interests is not in doubt. The arrest is constitutionally reasonable.” Virginia v. Moore, 553 U. S. 164, 171 (2008). The Fourth Amendment rule for searches is the same: Police officers are entitled to search regardless of the perceived triviality of the underlying law. *392As we have explained, requiring police to make “sensitive, case-by-case determinations of government need,” Atwater v. Lago Vista, 532 U. S. 318, 347 (2001), for a particular prohibition before conducting a search would “place police in an almost impossible spot,” id., at 350.

The majority has placed school officials in this “impossible spot” by questioning whether possession of ibuprofen and naproxen causes a severe enough threat to warrant investigation. Had the suspected infraction involved a street drug, the majority implies that it would have approved the scope of the search. See ante, at 376 (relying on the “limited threat of the specific drugs he was searching for”); ibid, (relying on the limited “power of the drugs” involved). In effect, then, the majority has replaced a school rule that draws no distinction among drugs with a new one that does. As a result, a full search of a student’s person for prohibited drugs will be permitted only if the Court agrees that the drug in question was sufficiently dangerous. Such a test is unworkable and unsound. School officials cannot be expected to halt searches based on the possibility that a court might later find that the particular infraction at issue is not severe enough to warrant an intrusive investigation.4

*393A rule promulgated by a school board represents the judgment of school officials that the rule is needed to maintain “school order” and “a proper educational environment.” T. L. O., 469 U. S., at 343, n. 9. Teachers, administrators, and the local school board are called upon both to “protect the... safety of students and school personnel” and “maintain an environment conducive to learning.” Id., at 353 (Blackmun, J., concurring in judgment). They are tasked with “watch[ing] over a large number of students” who “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.” Id., at 352. In such an environment, something as simple as a “water pistol or peashooter can wreak [havoc] until it is taken away.” Ibid. The danger posed by unchecked distribution and consumption of prescription pills by students certainly needs no elaboration.

Judges are not qualified to second-guess the best manner for maintaining quiet and order in the school environment. Such institutional judgments, like those concerning the selection of the best methods for “restraining students] from assaulting one another, abusing drugs and alcohol, and committing other crimes,” id., at 342, n. 9, “involve a host of policy choices that must be made by locally elected representatives, rather than by federal judges interpreting the basic charter of Government for the entire country,” Collins v. Harker Heights, 503 U. S. 115, 129 (1992); cf. Regents of Univ. of Mich. v. Ewing, 474 U. S. 214, 226 (1985) (observing that federal courts are not “suited to evaluating] the substance of the multitude of academic decisions” or disciplinary decisions “that are made daily by faculty members of public educa*394tional institutions”). It is a mistake for judges to assume the responsibility for deciding which school rules are important enough to allow for invasive searches and which rules are not.

3

Even if this Court were authorized to second-guess the importance of school rules, the Court’s assessment of the importance of this district’s policy is flawed. It is a crime to possess or use prescription-strength ibuprofen without a prescription. See Ariz. Rev. Stat. Ann. § 13-3406(A)(1) (West Supp. 2008) ("A person shall not knowingly . . . [possess or use a prescription-only drug unless the person obtains the prescription-only drug pursuant to a valid prescription of a prescriber who is licensed pursuant to [state law]”).5 By prohibiting unauthorized prescription drugs on school grounds — and conducting a search to ensure students abide by that prohibition — the school rule here was consistent with a routine provision of the state criminal code. It hardly seems unreasonable for school officials to enforce a rule that, in effect, proscribes conduct that amounts to a crime.

Moreover, school districts have valid reasons for punishing the unauthorized possession of prescription drugs on school *395property as severely as the possession of street drugs; “[tjeenage abuse of over-the-counter and prescription drugs poses an increasingly alarming national crisis.” Get Teens Off Drugs, 72 The Education Digest, No. 4, p. 75 (Dec. 2006). As one study noted, “more young people ages 12-17 abuse prescription drugs than any illicit drug except marijuana— more than cocaine, heroin, and methamphetamine combined.” Executive Office of the President, Office of National Drug Control Policy (ONDCP), Prescription for Danger 1 (Jan. 2008) (hereinafter Prescription for Danger). And according to a 2005 survey of teens, “nearly one in five (19 percent or 4.5 million) admit abusing prescription drugs in their lifetime.” Columbia University, The National Center on Addiction and Substance Abuse (CASA), “You’ve Got Drugs!” V: Prescription Drug Pushers on the Internet 2 (July 2008); see also Dept, of Health and Human Services, National Institute on Drug Abuse, High School and Youth Trends 2 (Dec. 2008) (“In 2008, 15.4 percent of 12th-graders reported using a prescription drug nonmedically within the past year”).

School administrators can reasonably conclude that this high rate of drug abuse is being fueled, at least in part, by the increasing presence of prescription drugs on school campuses. See, e. g., Gibson, Grand Forks Schools See Rise in Prescription Drug Abuse, Grand Forks Herald, Nov. 16, 2008, pp. Al, A6 (explaining that “prescription drug abuse is growing into a larger problem” as students “ ‘bring them to school and sell them or just give them to their friends’ ”). In a 2008 survey, “44 percent of teens sa[id] drugs are used, kept or sold on the grounds of their schools.” CASA, National Survey of American Attitudes on Substance Abuse XIII: Teens and Parents 19 (Aug. 2008) (hereinafter National Survey). The risks posed by the abuse of these drugs are every bit as serious as the dangers of using a typical street drug.

Teenagers are nevertheless apt to “believe the myth that these drugs provide a medically safe high.” ONDCP, Teens *396and Prescription Drugs: An Analysis of Recent Trends on the Emerging Drug Threat 3 (Feb. 2007) (hereinafter Teens and Prescription Drugs). But since 1999, there has “been a dramatic increase in the number of poisonings and even deaths associated with the abuse of prescription drugs.” Prescription for Danger 4; see also Dept. of Health and Human Services, The NSDUH Report: Trends in Nonmedical Use of Prescription Pain Relievers: 2002 to 2007, p. 1 (Feb. 5, 2009) (“[Approximately 324,000 emergency department visits in 2006 involved the nonmedical use of pain relievers”); CASA, Under the Counter: The Diversion and Abuse of Controlled Prescription Drugs in the U. S., p. 25 (July 2005) (“In 2002, abuse of controlled prescription drugs was implicated in at least 23 percent of drug-related emergency department admissions and 20.4 percent of all single drug-related emergency department deaths”). At least some of these injuries and deaths are likely due to the fact that “[m]ost controlled prescription drug abusers are poly-substance abusers,” id., at 3, a habit that is especially likely to result in deadly drug combinations. Furthermore, even if a child is not immediately harmed by the abuse of prescription drugs, research suggests that prescription drugs have become “gateway drugs to other substances of abuse.” Id., at 4; Healy, Skipping the Street, Los Angeles Times, Sept. 15,2008, p. FI (“Boomers made marijuana their ‘gateway’... but a younger generation finds prescription drugs are an easier score”); see also National Survey 17 (noting that teens report “that prescription drugs are easier to buy than beer”).

Admittedly, the ibuprofen and naproxen at issue in this case are not the prescription painkillers at the forefront of the prescription-drug-abuse problem. See Prescription for Danger 3 (“Pain relievers like Vicodin and OxyContin are the prescription drugs most commonly abused by teens”). But they are not without their own dangers. As nonsteroidal antiinflammatory drugs (NSAIDs), they pose a risk of death from overdose. The Pill Book 821, 827 (H. Silverman *397ed., 13th ed. 2008) (observing that ibuprofen and naproxen are NSAIDs and “[p]eople have died from NSAID overdoses”). Moreover, the side effects caused by the use of NSAIDs can be magnified if they are taken in combination with other drugs. See, e.g., Reactions Weekly, No. 1235, p. 18 (Jan. 17, 2009) (“A 17-year-old girl developed allergic interstitial nephritis and renal failure while receiving escitalopram and ibuprofen”); id., No. 1232, at 26 (Dec. 13, 2008) (“A 16-month-old boy developed iron deficiency anaemia and hypoalbuminaemia during treatment with naproxen”); id., No. 1220, at 15 (Sept. 20, 2008) (18-year-old “was diagnosed with pill-induced oesophageal perforation” after taking ibuprofen “and was admitted to the [intensive care unit]”); id., No. 1170, at 20 (Sept. 22, 2007) (“A 12-year-old boy developed anaphylaxis following ingestion of ibuprofen”).

If a student with a previously unknown intolerance to ibuprofen or naproxen were to take either drug and become ill, the public outrage would likely be directed toward the school for failing to take steps to prevent the unmonitored use of the drug. In light of the risks involved, a school’s decision to establish and enforce a school prohibition on the possession of any unauthorized drug is thus a reasonable judgment.6

* *

In determining whether the search’s scope was reasonable under the Fourth Amendment, it is therefore irrelevant whether officials suspected Redding of possessing *398prescription-strength ibuprofen, nonprescription-strength naproxen, or some harder street drug. Safford prohibited its possession on school property. Reasonable suspicion that Redding was in possession of drugs in violation of these policies, therefore, justified a search extending to any area where small pills could be concealed. The search did not violate the Fourth Amendment.

II

By declaring the search unreasonable in this case, the majority has “ ‘surrender[ed] control of the American public school system to public school students’” by invalidating school policies that treat all drugs equally and by second-guessing swift disciplinary decisions made by school officials. See Morse, 551 U. S., at 421 (Thomas, J., concurring) (quoting Tinker v. Des Moines Independent Community School Dist., 393 U. S. 503, 526 (1969) (Black, J., dissenting)). The Court’s interference in these matters of great concern to teachers, parents, and students illustrates why the most constitutionally sound approach to the question of applying the Fourth Amendment in local public schools would in fact be the complete restoration of the common-law doctrine of in loco parentis.

“[I]n the early years of public schooling,” courts applied the doctrine of in loco parentis to transfer to teachers the authority of a parent to “'command obedience, to control stubbornness, to quicken diligence, and to reform bad habits.’” Morse, supra, at 413-414 (Thomas, J., concurring) (quoting State v. Pendergrass, 19 N. C. 365, 365-366 (1837)). So empowered, schoolteachers and administrators had almost complete discretion to establish and enforce the rules they believed were necessary to maintain control over their classrooms. See 2 J. Kent, Commentaries on American Law *205 (“So the power allowed by law to the parent over the person of the child may be delegated to a tutor or instructor, the better to accomplish the purpose of education”); 1 W. *399Blackstone, Commentaries on the Laws of England 441 (1765) (“He may also 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”).7 The perils of judicial policy-making inherent in applying Fourth Amendment protections to public schools counsel in favor of a return to the understanding that existed in this Nation’s first public schools, which gave teachers discretion to craft the rules needed to carry out the disciplinary responsibilities delegated to them by parents.

If the common-law view that parents delegate to teachers their authority to discipline and maintain order were to be applied in this case, the search of Redding would stand. There can be no doubt that a parent would have had the authority to conduct the search at issue in this ease. Parents have “immunity from the strictures of the Fourth Amendment” when it comes to searches of a child or that child’s belongings. T. L. O., 469 U. S., at 337; see also id., at 336 (A parent’s authority is “not subject to the limits of the Fourth Amendment”); Griffin v. Wisconsin, 483 U. S. 868, 876 (1987) (“[P]arental custodial authority” does not require “judicial approval for [a] search of a minor child’s room”).

As acknowledged by this Court, this principle is based on the “societal understanding of superior and inferior” with respect to the “parent and child” relationship. Georgia v. Randolph, 547 U. S. 103, 114 (2006). In light of this relation*400ship, the Court has indicated that a parent can authorize a third-party search of a child by consenting to such a search, even if the child denies his consent. See ibid.; see also 4 W. LaFave, Search and Seizure § 8.3(d), p. 160 (4th ed. 2004) (“[A] father, as the head of the household with the responsibility and the authority for the discipline, training and control of his children, has a superior interest in the family residence to that of his minor son, so that the father’s consent to search would be effective notwithstanding the son’s contemporaneous on-the-scene objection” (internal quotation marks omitted)). Certainly, a search by the parent himself is no different, regardless of whether or not a child would prefer to be left alone. See id., § 8.4(b), at 202 (“[E]ven [if] a minor child . . . may think of a room as ‘his,’ the overall dominance will be in his parents” (some internal quotation marks omitted)).

Restoring the common-law doctrine of in loco parentis would not, however, leave public schools entirely free to impose any rule they choose. “If parents do not like the rules imposed by those schools, they can seek redress in school boards or legislatures; they can send their children to private schools or homeschool them; or they can simply move.” See Morse, supra, at 420 (Thomas, J., concurring). Indeed, parents and local government officials have proved themselves quite capable of challenging overly harsh school rules or the enforcement of sensible rules in insensible ways.

For example, one community questioned a school policy that resulted in “an 11-year-old [being] arrested, handcuffed and taken to jail for bringing a plastic butter knife to school.” Downey, Zero Tolerance Doesn’t Always Add Up, Atlanta Journal-Constitution, Apr. 6, 2009, p. All. In another, “[a]t least one school board member was outraged” when 14 elementary-school students were suspended for “imitating drug activity” after they combined Kool-Aid and sugar in plastic bags. Grant, Pupils Trading Sweet Mix Get Sour *401Shot of Discipline, Pittsburgh Post-Gazette, May 18, 2006, pp. Bl, B2. Individuals within yet another school district protested a “‘zero-tolerance’ policy toward weapons” that had become “ ‘so rigid that it force[d] schools to expel any student who belongs to a military organization, a drum-and-bugle corps or any other legitimate extracurricular group and is simply transporting what amounts to harmless props.’” Richardson, School Gun Case Sparks Cries For “Common Sense,” Washington Times, Feb. 13-14, 2009, pp. Al, A9.8

These local efforts to change controversial school policies through democratic processes have proved successful in many cases. See, e. g., Postal, Schools’ Zero Tolerance Could Lose Some Punch, Orlando Sentinel, Apr. 24, 2009, p. B3 (“State lawmakers want schools to dial back strict zero-tolerance policies so students do not end up in juvenile detention for some ‘goofy thing’”); Richardson, Tolerance Waning for Zero-tolerance Rules, Washington Times, Apr. 21, 2009, p. A3 (“[A] few states have moved to relax their laws. Utah now allows students to bring asthma inhalers to school without violating the zero-tolerance policy on *402drugs”); see also Nussbaum, Becoming Fed Up With Zero Tolerance, N. Y. Times, Sept. 3, 2000, section 14, pp. 1, 8 (discussing a report that found that “widespread use of zero-tolerance discipline policies was creating as many problems as it was solving and that there were many cases around the country in which students were harshly disciplined for infractions where there was no harm intended or done”).

In the end, the task of implementing and amending public school policies is beyond this Court’s function. Parents, teachers, school administrators, local politicians, and state officials are all better suited than judges to determine the appropriate limits on searches conducted by school officials. Preservation of order, discipline, and safety in public schools is simply not the domain of the Constitution. And, common sense is not a judicial monopoly or a constitutional imperative.

Ill

“[T]he nationwide drug epidemic makes the war against drugs a pressing concern in every school.” Board of Ed. of Independent School Dist. No. 92 of Pottawatomie Cty. v. Earls, 536 U. S. 822, 834 (2002). And yet the Court has limited the authority of school officials to conduct searches for the drugs that the officials believe pose a serious safety risk to their students. By doing so, the majority has confirmed that a return to the doctrine of in loco parentis is required to keep the judiciary from essentially seizing control of public schools. Only then will teachers again be able to “ 'govern the[ir] pupils, quicken the slothful, spur the indolent, restrain the impetuous, and control the stubborn’ ” by making “ 'rules, giv[ing] commands, and punish[ing] disobedience’” without interference from judges. Morse, 551 U. S., at 414 (Thomas, J., concurring). By deciding that it is better equipped to decide what behavior should be permitted in schools, the Court has undercut student safety and undermined the authority of school administrators and local officials. Even more trou*403bling, it has done so in a case in which the underlying response by school administrators was reasonable and justified. I cannot join this regrettable decision. I, therefore, respectfully dissent from the Court’s determination that this search violated the Fourth Amendment.