Mr. Justice White

announced the judgment of the Court and an opinion in which The Chief Justice, Mr. Justice Stewart, and Mr. Justice Blackmun join.

In 1966, respondent James A. White was tried and convicted under two consolidated indictments charging various illegal transactions in narcotics violative of 26 U. S. C. § 4705 (a) and 21 U. S. C. § 174. He was fined and sentenced as a second offender to 25-year concurrent sentences. The issue before us is whether the Fourth Amendment bars from evidence the testimony of governmental agents who related certain conversations which had occurred between defendant White and a government informant, Harvey Jackson, and which the agents *747overheard by monitoring the frequency of a radio transmitter carried by Jackson and concealed on his person.1 On four occasions the conversations took place in Jackson’s home; each of these conversations was overheard by an agent concealed in a kitchen closet with Jackson’s consent and by a second agent outside the house using a radio receiver. Four other conversations — one in respondent’s home, one in a restaurant, and two in Jackson’s car — were overheard by the use of radio equipment. The prosecution was unable to locate and produce Jackson at the trial and the trial court overruled objections to the testimony of the agents who conducted the electronic surveillance. The jury returned a guilty verdict and defendant appealed.

The Court of Appeals read Katz v. United States, 389 U. S. 347 (1967), as overruling On Lee v. United States, 343 U. S. 747 (1952), and interpreting the Fourth Amendment to forbid the introduction of the agents’ testimony in the circumstances of this case. Accordingly, the court reversed but without adverting to the fact that the transactions at issue here had occurred before Katz was decided in this Court. In our view, the Court of Appeals misinterpreted both the Katz case and the Fourth Amendment and in any event erred in applying the Katz case to events that occurred before that decision was rendered by this Court.2

*748I

Until Katz v. United States, neither wiretapping nor electronic eavesdropping violated a defendant's Fourth Amendment rights “unless there has been an official search and seizure of his person, or such a seizure of his papers or his tangible material effects, or an actual physical invasion of his house 'or curtilage’ for the purpose of making a seizure.” Olmstead v. United States, 277 U. S. 438, 466 (1928); Goldman v. United States, 316 U. S. 129, 135-136 (1942). But where “eavesdropping was accomplished by means of an unauthorized physical penetration into the premises occupied” by the defendant, although falling short of a “technical trespass under the local property law,” the Fourth Amendment was violated and any evidence of what was seen and heard, as well as tangible objects seized, was considered the inadmissible fruit of an unlawful invasion. Silverman v. United States, 365 U. S. 505, 509, 511 (1961); see also Wong Sun v. United States, 371 U. S. 471 (1963); Berger v. New York, 388 U. S. 41, 52 (1967); Alderman v. United States, 394 U. S. 165, 177-178 (1969).

Katz v. United States, however, finally swept away doctrines that electronic eavesdropping is permissible under the Fourth Amendment unless physical invasion of a constitutionally protected area produced the challenged evidence. In that case government agents, without petitioner’s consent or knowledge, attached a listening device to the outside of a public telephone booth and recorded the defendant’s end of his telephone conversations. In declaring the recordings inadmissible in evidence in the absence of a warrant authorizing the surveillance, the Court overruled Olmstead and Goldman and held that the absence of physical intrusion into the telephone booth did not-justify using electronic devices in listening to and recording Katz’ words, thereby vio*749lating the privacy on which he justifiably relied while using the telephone in those circumstances.

The Court of Appeals understood Katz to render inadmissible against White the agents’ testimony concerning conversations that Jackson broadcast to them. We cannot agree. Katz involved no revelation to the Government by a party to conversations with the defendant nor did the Court indicate in any way that a defendant has a justifiable and constitutionally protected expectation that a person with whom he is conversing will not then or later reveal the conversation to the police.

Hoffa v. United States, 385 U. S. 293 (1966), which was left undisturbed by Katz, held that however strongly a defendant may trust an apparent colleague, his expectations in this respect are not protected by the Fourth Amendment when it turns out that the colleague is a government agent regularly communicating with the authorities. In these circumstances, “no interest legitimately protected by the Fourth Amendment is involved,” for that amendment affords no protection to “a wrongdoer’s misplaced belief that a person to whom he voluntarily confides his wrongdoing will not reveal it.” Hoffa v. United States, at 302. No warrant to “search and seize” is required in such circumstances, nor is it when the Government sends to defendant’s home a secret agent who conceals his identity and makes a purchase of narcotics from the accused, Lewis v. United States, 385 U. S. 206 (1966), or when the same agent, unbeknown to the defendant, carries electronic equipment to record the defendant’s words and the evidence so gathered is later offered in evidence. Lopez v. United States, 373 U. S. 427 (1963).

Conceding that Hoffa, Lewis, and Lopez remained unaffected by Katz, 3 the Court of Appeals nevertheless *750read both Katz and the Fourth Amendment to require a different result if the agent not only records his conversations with the defendant but instantaneously transmits them electronically to other agents equipped with radio receivers. Where this occurs, the Court of Appeals held, the Fourth Amendment is violated and the testimony of the listening agents must be excluded from evidence.

To reach this result it was necessary for the Court of Appeals to hold that On Lee v. United States was no longer good law. In that case, which involved facts very similar to the case before us, the Court first rejected claims of a Fourth Amendment violation because the informer had not trespassed when he entered the defendant's premises and conversed with him. To this extent the Court’s rationale cannot survive Katz. See 389 U. S., at 352-353. But the Court announced a second and independent ground for its decision; for it went on to say that overruling Olmstead and Goldman would be of no aid to On Lee since he “was talking confidentially and indiscreetly with one he trusted, and he was overheard. ... It would be a dubious service to the genuine liberties protected by the Fourth Amendment to make them bedfellows with spurious liberties improvised by farfetched analogies which would liken eavesdropping on a conversation, with the connivance of one of the parties, to an unreasonable search or seizure. We find no violation of the Fourth Amendment here.” 343 U. S., at 753-754. We see no indication in Katz that the Court meant to disturb that understanding of the Fourth Amendment or to disturb the result reached in the On Lee case,4 nor are we now inclined to overturn this view of the Fourth Amendment.

*751Concededly a police agent who conceals his police connections may write down for official use his conversations with a defendant and testify concerning them, without a warrant authorizing his encounters with the defendant and without otherwise violating the latter’s Fourth Amendment rights. Hoffa v. United States, 385 U. S., at 300-303. For constitutional purposes, no' different result is required if the agent instead of immediately reporting and transcribing his conversations with defendant, either (1) simultaneously records them with electronic equipment which he is carrying on his person, Lopez v. United States, supra; (2) or carries radio equipment which simultaneously transmits the conversations either to recording equipment located elsewhere or to other agents monitoring the transmitting frequency. On Lee v. United States, supra. If the conduct and revelations of an agent operating without electronic equipment do not invade the defendant’s constitutionally justifiable expectations of privacy, neither does a simultaneous recording of the same conversations made by the agent or by others from transmissions received from the agent to whom the defendant is talking and whose trustworthiness the defendant necessarily risks.

Our problem is not what the privacy expectations of particular defendants in particular situations may be or the extent to which they may in fact have relied on the discretion of their companions. Very probably, individual defendants neither know nor suspect that their colleagues have gone or will go to the police or are carrying recorders or transmitters. Otherwise, conversation would cease and our problem with these encounters would be nonexistent or far different from those now *752before us. Our problem, in terms of the principles announced in Katz, is what expectations of privacy are constitutionally “justifiable”' — what expectations the Fourth Amendment will protect in the absence of a warrant. So far, the law permits the frustration of actual expectations of privacy by permitting authorities to use the testimony of those associates who for one reason or another have determined to turn to the police, as well as by authorizing the use of informants in the manner exemplified by Hoff a and Lewis. If the law gives no protection to the wrongdoer whose trusted accomplice is or becomes a police agent, neither should it protect him when that same agent has recorded or transmitted the conversations which are later offered in evidence to prove the State’s case. See Lopez v. United States, 373 U. S. 427 (1963).

Inescapably, one contemplating illegal activities must realize and risk that his companions may be reporting to the police. If he sufficiently doubts their trustworthiness, the association will very probably end or never materialize. But if he has no doubts, or allays them, or risks what doubt he has, the risk is his. In terms of what his course will be, what he will or will not do or say, we are unpersuaded that he would distinguish between probable informers on the one hand and probable informers with transmitters on the other. Given the possibility or probability that one of his colleagues is cooperating with the police, it is only speculation to assert that the defendant’s utterances would be substantially different or his sense of security any less if he also thought it possible that the suspected colleague is wired for sound. At least there is no persuasive evidence that the difference in this respect between the electronically equipped and the unequipped agent is substantial enough to require discrete constitutional recog-*753ration, particularly under the Fourth Amendment which is ruled by fluid concepts of “reasonableness.”

Nor should we be too ready to erect constitutional barriers to relevant and probative evidence which is also accurate and reliable. An electronic recording will many times produce a more reliable rendition of what a defendant has said than will the unaided memory of a police agent. It may also be that with the recording in existence it is less likely that the informant will change his mind, less chance that threat or injury will suppress unfavorable evidence and less chance that cross-examination will confound the testimony. Considerations like these obviously do not favor the defendant, but we are not prepared to hold that a defendant who has no constitutional right to exclude the informer’s unaided testimony nevertheless has a Fourth Amendment privilege against a more accurate version of the events in question.

It is thus untenable to consider the activities and reports of the police agent himself, though acting without a warrant, to be a “reasonable” investigative effort and lawful under the Fourth Amendment but to view the same agent with a recorder or transmitter as conducting an “unreasonable” and unconstitutional search and seizure. Our opinion is currently shared by Congress and the Executive Branch, Title III, Omnibus Crime Control and Safe Streets Act of 1968, 82 Stat. 212, 18 U. S. C. §2510 et seq. (1964 ed., Supp. V), and the American Bar Association. Project on Standards for Criminal Justice, Electronic Surveillance § 4.1 (Approved Draft 1971). It is also the result reached by prior cases in this Court. On Lee, supra; Lopez v. United States, supra.

No different result should obtain where, as in On Lee and the instant case, the informer disappears and is un*754available at trial; for the issue of whether specified events on a certain day violate the Fourth Amendment should not be determined by what later happens to the informer. His unavailability at trial and proffering the testimony of other agents may raise evidentiary problems or pose issues of prosecutorial misconduct with respect to the informer’s disappearance, but they do not appear critical to deciding whether prior events invaded the defendant’s Fourth Amendment rights.

II

The Court of Appeals was in error for another reason. In Desist v. United States, 394 U. S. 244 (1969), we held that our decision in Katz v. United States applied only to those electronic surveillances that occurred subsequent to the date of that decision. Here the events in question took place in late 1965 and early 1966, long prior to Katz. We adhere to the rationale of Desist, see Williams v. United States, ante, p. 646. It was error for the Court of Appeals to dispose of this case based on its understanding of the principles announced in the Katz case. The court should have judged this case by the pr e-Katz law and under that law, as On Lee clearly holds, the electronic surveillance here involved did not violate White’s rights to be free from unreasonable searches and seizures.

The judgment of the Court of Appeals is reversed.

It is so ordered.

Mr. Justice Black, while adhering to his views expressed in Linkletter v. Walker, 381 U. S. 618, 640 (1965), concurs in the judgment of the Court for the reasons set forth in his dissent in Katz v. United States, 389 U. S. 347, 364 (1967).

*755Mr. Justice Brennan,

concurring in the result.

I agree that Desist v. United States, 394 U. S. 244 (1969), requires reversal of the judgment of the Court of Appeals. Therefore, a majority of the Court supports disposition of this case on that ground. However, my Brothers Douglas, Harlan, and White also debate the question whether On Lee v. United States, 343 U. S. 747 (1952), may any longer be regarded as sound law. My Brother White argues that On Lee is still sound law. My Brothers Douglas and Harlan argue that it is not. Neither position commands the support of a majority of the Court. For myself, I agree with my Brothers Douglas and Harlan. But I go further. It is my view that the reasoning of both my Brothers Douglas and Harlan compels the conclusion that Lopez v. United States, 373 U. S. 427 (1963), is also no longer sound law. In other words, it is my view that current Fourth Amendment jurisprudence interposes a warrant requirement not only in cases of third-party electronic monitoring (the situation in On Lee and in this case) but also in cases of electronic recording by a government agent of a face-to-face conversation with a criminal suspect, which was the situation in Lopez. For I adhere to the dissent in Lopez, 373 U. S., at 446-471, in which, to quote my Brother Harlan, post, at 778 n. 12, “the doctrinal basis of our subsequent Fourteenth Amendment decisions may be said to have had its genesis.” Katz v. United States, 389 U. S. 347 (1967), adopted that “doctrinal basis” and thus, it seems to me, agreed with the argument in the Lopez dissent that “subsequent decisions and subsequent experience have sapped whatever vitality [On Lee] may once have had; that it should now be regarded as overruled” and that the situation in Lopez “is rationally indistinguishable.” 373 U. S., at 447. The reasons in support of those conclusions are set forth fully in the Lopez *756dissent and need not be repeated here. It suffices to say that for those reasons I remain of the view that the Fourth Amendment imposes the warrant requirement in both the On Lee and Lopez situations.

Mr. Justice Douglas,

dissenting.

I

The issue in this case is clouded and concealed by the very discussion of it in legalistic terms. What the ancients knew as “eavesdropping,” we now call “electronic surveillance”; but to equate the two is to treat man’s first gunpowder on the same level as the nuclear bomb. Electronic surveillance is the greatest leveler of human privacy ever known. How most forms of it can be held “reasonable” within the meaning of the Fourth Amendment is a mystery. To be sure, the Constitution and Bill of Rights are not to be read as covering only the technology known in the 18th century. Otherwise its concept of “commerce” would be hopeless when it comes to the management of modern affairs. At the same time the concepts of privacy which the Founders enshrined in the Fourth Amendment vanish completely when we slavishly allow an all-powerful government, proclaiming law and order, efficiency, and other benign purposes, to penetrate all the walls and doors which men need to shield them from the pressures of a turbulent life around them and give them the health and strength to carry on.

That is why a “strict construction” of the Fourth Amendment is necessary if every man’s liberty and privacy are to be constitutionally honored.

When Franklin D. Roosevelt on May 21, 1940, authorized wiretapping in cases of “fifth column” activities and sabotage and limited it “insofar as possible to aliens,” he said that “under ordinary and normal circumstances *757wire-tapping by Government agents should not be carried on for the excellent reason that it is almost bound to lead to abuse of civil rights.” See Appendix I to this dissent. Yet as Judge Ferguson said in United States v. Smith, 321 F. Supp. 424, 429:

“[T]he government seems to approach these dissident domestic organizations in the same fashion as it deals with unfriendly foreign powers. The government cannot act in this manner when only domestic political organizations are involved, even if those organizations espouse views which are inconsistent with our present form of government. To do so is to ride roughshod over numerous political freedoms which have long received constitutional protection. The government can, of course, investigate and prosecute criminal violations whenever these organizations, or rather their individual members, step over the line of political theory and general advocacy and commit illegal acts.”

Today no one perhaps notices because only a small, obscure criminal is the victim. But every person is the victim, for the technology we exalt today is everyman’s master. Any doubters should read Arthur R. Miller’s The Assault On Privacy (1971). After describing the monitoring of conversations and their storage in data banks, Professor Miller goes on to describe “human monitoring” which he calls the “ultimate step in mechanical snooping” — a device for spotting unorthodox or aberrational behavior across a wide spectrum. “Given the advancing state of both the remote sensing art and the capacity of computers to handle an uninterrupted and synoptic data flow, there seem to be no physical barriers left to shield us from intrusion.” Id., at 46.

When one reads what is going on in this area today, our judicial treatment of the subject seems as remote from *758reality as the well-known Baron Parke was remote from the social problems of his day. See Chapman, “Big Brother” in the Justice Department, The Progressive, April 1971, p. 27.

II

We held in Berger v. New York, 388 U. S. 41, that wiretapping is a search and seizure within the meaning of the Fourth Amendment and therefore must meet its requirements, viz., there must be a prior showing of probable cause, the warrant authorizing the wiretap must particularly describe “the place to be searched, and the persons or things to be seized,” and that it may not have the breadth, generality, and long life of the general warrant against which the Fourth Amendment was aimed.

In Katz v. United States, 389 U. S. 347, we held that an electronic device, used without trespass onto any given enclosure (there a telephone booth), was a search for which a Fourth Amendment warrant was needed.1 Mr. Justice Stewart, speaking for the Court, said: “Wherever a man may be, he is entitled to know that he will remain free from unreasonable searches and seizures.” Id., at 359.

As a result of Berger and of Katz, both wiretapping and electronic surveillance through a “bug” or other device are now covered by the Fourth Amendment.

There were prior decisions representing an opposed view. In On Lee v. United States, 343 U. S. 747, an *759undercover agent with a radio transmitter concealed on his person interviewed the defendant whose words were heard over a radio receiver by another agent down the street. The idea, discredited by Katz, that there was no violation of the Fourth Amendment because there was no trespass, was the core of the On Lee decision. Id., at 751-754.

Lopez v. United States, 373 U. S. 427, was also pre-Berger and pre-Katz. The government agent there involved carried a pocket wire recorder which the Court said “was not planted by means of an unlawful physical invasion of petitioner’s premises under circumstances which would violate the Fourth Amendment.” Id., at 439.

Mr. Justice Brennan, dissenting, stated the philosophy of Katz soon to be adopted:

“[T]here is a qualitative difference between electronic surveillance, whether the agents conceal the devices on their persons or in walls or under beds, and conventional police stratagems such as eavesdropping and disguise. The latter do not so seriously intrude upon the right of privacy. The risk of being overheard by an eavesdropper or betrayed by an informer or deceived as to the identity of one with whom one deals is probably inherent in the conditions of human society. It is the kind of risk we necessarily assume whenever we speak. But as soon as electronic surveillance comes into play, the risk changes crucially. There is no security from that kind of eavesdropping, no way of mitigating the risk, and so not even a residuum of true privacy. . . .

“. . . Electronic aids add a wholly new dimension to eavesdropping. They make it more penetrating, more indiscriminate, more truly obnoxious to a free *760society. Electronic surveillance, in fact, makes the police omniscient; and police omniscience is one of the most effective tools of tyranny.” 373 U. S., at 465-466.

It is urged by the Department of Justice that On Lee be established as the controlling decision in this field. I would stand by Berger and Katz and reaffirm the need for judicial supervision2 under the Fourth Amendment of the use of electronic surveillance which, uncontrolled, promises to lead us into a police state.

These were wholly pre-arranged episodes of surveillance. The first was in the informant’s home to which respondent had been invited. The second was also in the informer’s home, the next day. The third was four days later at the home of the respondent. The fourth was in the informer’s car two days later. Twelve days after that a meeting in the informer’s home was intruded upon. The sixth occurred at a street rendezvous. The seventh was in the informer’s home and the eighth in a restaurant owned by respondent’s mother-in-law. So far as time is concerned there is no excuse for not seeking a warrant. And while there is always an effort involved in preparing affidavits or other evidence in support of a showing of probable cause, that burden was given constitutional sanction in the Fourth Amendment against the activities of the agents of George III. It was designed not to protect criminals but to protect everyone’s privacy.

On Lee and Lopez are of a vintage opposed to Berger and Katz. However they may be explained, they are *761products of the old common-law notions of trespass. Katz, on the other hand, emphasized that with few exceptions “searches conducted outside the judicial process, without prior approval by judge or magistrate, are per se unreasonable under the Fourth Amendment . . , 389 U. S., at 357. Camara v. Municipal Court, 387 U. S. 523, put administrative searches under the Fourth Amendment. We held that administrative actions, like other searches, implicated officials in an invasion of privacy and that the Fourth Amendment was meant to guard against the arbitrariness of any such invasion. We said:

“We simply cannot say that the protections provided by the warrant procedure are not needed in this context; broad statutory safeguards are no substitute for individualized review, particularly when those safeguards may only be invoked at the risk of a criminal penalty.” Id., at 533.

In Chimel v. California, 395 U. S. 752, in considering the constitutionality of a search incident to an arrest we held that, while the area in the immediate reach of an arrestee is “reasonable” though made without a warrant, a search beyond that zone may generally be made “only under the authority of a search warrant.” Id., at 763. And in two “stop and frisk” cases, Terry v. Ohio, 392 U. S. 1, and Davis v. Mississippi, 394 U. S. 721, we held that any restraint of the person, however brief, was subject to judicial inquiry on “reasonableness” (392 U. S., at 19) and that “the Fourth Amendment governs all intrusions by agents of the public upon personal security . . . .” Id., at 18 n. 15.

We have moved far away from the rationale of On Lee and Lopez and only a retrogressive step of large dimensions would bring us back to it.

The threads of thought running through our recent decisions are that these extensive intrusions into privacy *762made by electronic surveillance make self-restraint by law enforcement officials an inadequate protection, that the requirement of warrants under the Fourth Amendment is essential to a free society.3

Monitoring, if prevalent, certainly kills free discourse and spontaneous utterances. Free discourse — a First Amendment value — may be frivolous or serious, humble or defiant, reactionary or revolutionary, profane or in good taste; but it is not free if there is surveillance.4 *763Free discourse liberates the spirit, though it may produce only froth. The individual must keep some facts concerning his thoughts within a small zone of people. At the same time he must be free to pour out his woes or inspirations or dreams to others. He remains the sole judge as to what must be said and what must remain unspoken. This is the essence of the idea of privacy implicit in the First and Fifth Amendments as well as in the Fourth.

The philosophy of the value of privacy reflected in the Fourth Amendment’s ban on “unreasonable searches and seizures” has been forcefully stated by a former Attorney General of the United States:

“Privacy is the basis of individuality. To be alone and be let alone, to be with chosen company, to say what you think, or don’t think, but to say what you will, is to be yourself. Solitude is imperative, even in a high rise apartment. Personality develops from within. To reflect is to know yourself. Character is formed through years of self-examination. Without this opportunity, character will be formed largely by uncontrolled external social stimulations. Americans are excessively homogenized already.

“Few conversations would be what they are if the speakers thought others were listening. Silly, secret, thoughtless and thoughtful statements would all be affected. The sheer numbers in our lives, the anonymity of urban living and the inability to influence things that are important are depersonalizing and dehumanizing factors of modern life. To penetrate the last refuge of the individual, the precious little privacy that remains, the basis of individual dignity, can have meaning to the quality of our lives that we cannot foresee. In terms of present values, that meaning cannot be good.

*764“Invasions of privacy demean the individual. Can a society be better than the people composing it? When a government degrades its citizens, or permits them to degrade each other, however beneficent the specific purpose, it limits opportunities for individual fulfillment and national accomplishment. If America permits fear and its failure to make basic social reforms to excuse police use of secret electronic surveillance, the price will be dear indeed. The practice is incompatible with a free society.” R. Clark, Crime in America 287 (1970).

Now that the discredited decisions in On Lee and Lopez are resuscitated and revived, must everyone live in fear that every word he speaks may be transmitted or recorded 5 and later repeated to the entire world? I can *765imagine nothing that has a more chilling effect on people speaking their minds and expressing their views on important matters. The advocates of that regime should spend some time in totalitarian countries and learn firsthand the kind of regime they are creating here.6

*766Ill

The decision not to make Katz retroactive to any electronic surveillance which occurred prior to December 18, 1967 (the day we decided Katz), is not, in my view, a tenable one for the reasons stated by Mr. Justice Harlan and me in our dissents in Desist v. United States, 394 U. S. 244, 255, 256.

APPENDIX I TO OPINION OP DOUGLAS, J., DISSENTING

THE WHITE HOUSE WASHINGTON

May 21, 1940

CONFIDENTIAL

MEMORANDUM FOR THE ATTORNEY GENERAL

I have agreed with the broad purpose of the Supreme Court decision relating to wire-tapping in investigations. The Court is undoubtedly sound both in regard to the use of evidence secured over tapped wires in the prosecution of citizens in criminal cases; and is also right in its opinion that under ordinary and normal circumstances wire-tapping by Government agents should not be carried on for the excellent reason that it is almost bound to lead to abuse of civil rights.

However, I am convinced that the Supreme Court never intended any dictum in the particular case which it decided to apply to grave matters involving the defense of the nation.

It is, of course, well known that certain other nations have been engaged in the organization of propaganda of so-called “fifth columns” in other countries and in preparation for sabotage, as well as in actual sabotage.

*767It is too late to do anything about it after sabotage, assassinations and “fifth column” activities are completed.

You are, therefore, authorized and directed in such cases as you may approve, after investigation of the need in each case, to authorize the necessary investigation agents that they are at liberty to secure information by listening devices directed to the conversation or other communications of persons suspected of subversive activities against the Government of the United States, including suspected spies. You are requested furthermore to limit these investigations so conducted to a minimum and to limit them insofar as possible to aliens.

[seal] /s/ F. D. R.

APPENDIX II TO OPINION OF DOUGLAS, J., DISSENTING

ADMINISTRATIVELY CONFIDENTIAL THE WHITE HOUSE WASHINGTON

June 30, 1965

MEMORANDUM FOR THE HEADS OF EXECUTIVE DEPARTMENTS AND AGENCIES

I am strongly opposed to the interception of telephone conversations as a general investigative technique. I recognize that mechanical and electronic devices may sometimes be essential in protecting our national security. Nevertheless, it is clear that indiscriminate use of those investigative devices to overhear telephone conversations, without the knowledge or consent of any of the persons involved, could result in serious abuses and invasions of privacy. In my view, the invasion of privacy of communications is a highly offensive practice which should be engaged in only where the national security is at *768stake. To avoid any misunderstanding on this subject in the Federal Government, I am establishing the following basic guidelines to be followed by all government agencies:

(1) No federal personnel is to intercept telephone conversations within the United States by any mechanical or electronic device, without the consent of one of the parties involved, (except in connection with investigations related to the national security).

(2) No interception shall be undertaken or continued without first obtaining the approval of the Attorney General.

(3) All federal agencies shall immediately conform their practices and procedures to the provisions of this order.

Utilization of mechanical or electronic devices to overhear non-telephone conversations is an even more difficult problem, which raises substantial and unresolved questions of Constitutional interpretation. I desire that each agency conducting such investigations consult with the Attorney General to ascertain whether the agency’s practices are fully in accord with the law and with a decent regard for the rights of others.

Every agency head shall submit to the Attorney General within 30 days a complete inventory of all mechanical and electronic equipment and devices used for or capable of intercepting telephone conversations. In addition, such reports shall contain a list of any interceptions currently authorized and the reasons for them.

/s/ Lyndon B. Johnson

Mr. Justice Harlan,

dissenting.

The uncontested facts of this case squarely challenge the continuing viability of On Lee v. United States, 343 U. S. 747 (1952). As the plurality opinion of Mr. Jus*769tice White itself makes clear, important constitutional developments since On Lee mandate that we reassess that case, which has continued to govern official behavior of this sort in spite of the subsequent erosion of its doctrinal foundations. With all respect, my agreement with the plurality opinion ends at that point.

I think that a perception of the scope and role of the Fourth Amendment, as elucidated by this Court since On Lee was decided, and full comprehension of the precise issue at stake lead to the conclusion that On Lee can no longer be regarded as sound law. Nor do I think the date we decided Katz v. United States, 389 U. S. 347 (1967), can be deemed controlling both for the reasons discussed in my dissent in Desist v. United States, 394 U. S. 244, 256 (1969), and my separate opinion in Mackey v. United States (and companion cases), ante, p. 675 (the case before us being here on direct review), and because, in my view, it requires no discussion of the holding in Katz, as distinguished from its underlying rationale as to the reach of the Fourth Amendment, to comprehend the constitutional infirmity of On Lee.

I

Before turning to matters of precedent and policy, several preliminary observations should be made. We deal here with the constitutional validity of instantaneous third-party electronic eavesdropping, conducted by federal law enforcement officers, without any prior judicial approval of the technique utilized, but with the consent and cooperation of a participant in the conversation,1 *770and where the substance of the matter electronically overheard2 is related in a federal criminal trial by those who eavesdropped as direct, not merely corroborative, evidence of the guilt of the nonconsenting party. The magnitude of the issue at hand is evidenced not simply by the obvious doctrinal difficulty of weighing such activity in the Fourth Amendment balance, but also, and more importantly, by the prevalence of police utilization of this technique. Professor Westin has documented in careful detail the numerous devices that make technologically feasible the Orwellian Big Brother. Of immediate relevance is his observation that “ 'participant recording/ in which one participant in a conversation or meeting, either a police officer or a co-operating party, wears a concealed device that records the conversation or broadcasts it to others nearby ... is used tens of thousands of times each year throughout the country, particularly in cases involving extortion, conspiracy, narcotics, gambling, prostitution, corruption by police officials . . . and similar crimes.” 3

*771Moreover, as I shall undertake to show later in this opinion, the factors that must be reckoned with in reaching constitutional conclusions respecting the use of electronic eavesdropping as a tool of law enforcement are exceedingly subtle and complex. They have provoked sharp differences of opinion both within and without the judiciary, and the entire problem has been the subject of continuing study by various governmental and nongovernmental bodies.4

*772Finally, given the importance of electronic eavesdropping as a technique for coping with the more deep-seated kinds of criminal activity, and the complexities that are encountered in striking a workable constitutional balance between the public and private interests at stake, I believe that the courts should proceed with specially measured steps in this field. More particularly, I think this Court should not foreclose itself from reconsidering doctrines that would prevent the States from seeking, independently of the niceties of federal restrictions as they may develop, solutions to such vexing problems, see Mapp v. Ohio, 367 U. S. 643 (1961), and Ker v. California, 374 U. S. 23 (1963), and see also Berger v. New York, 388 U. S. 41 (1967); Baldwin v. New York, 399 U. S. 66, 117 (1970) (dissenting opinion); California v. Green, 399 U. S. 149, 172 (1970) (concurring opinion). I also think that in the adjudication of federal cases, the Court should leave ample room for congressional developments.

*773II

On these premises I move to the problem of third-party “bugging.” To begin by tracing carefully the evolution of Fourth Amendment doctrine in post-Ow Lee decisions has proved useful in several respects. It serves to cast in perspective both the issue involved here and the imperative necessity for reconsidering On Lee afresh. Additionally, a full exposition of the dynamics of the decline of the trespass rationale underlying On Lee strikingly illuminates the deficiencies of the plurality opinion’s retroactivity analysis.

A

On Lee involved circumstances virtually identical to those now before us. There, Government agents enlisted the services of Chin Poy, a former friend of Lee, who was suspected of engaging in illegal narcotics traffic. Poy was equipped with a “minifon” transmitting device which enabled outside Government agents to monitor Poy’s conversations with Lee. In the privacy of his laundry, Lee made damaging admissions to Poy which were overheard by the agents and later related at trial. Poy did not testify. Mr. Justice Jackson, writing for five Justices, held the testimony admissible. Without reaching the question of whether a conversation could be the subject of a “seizure” for Fourth Amendment purposes, as yet an unanswered if not completely open question,5 the *774Court concluded that in the absence of a trespass,6 no constitutional violation had occurred.7

The validity of the trespass rationale was questionable even at the time the decision was rendered. In this respect On Lee rested on common-law notions and looked to a waning era of Fourth Amendment jurisprudence. Three members of the Court refused to join with Justice Jackson, and within 10 years the Court expressly disavowed an approach to Fourth Amendment questions that looked to common-law distinctions. See, e. g., Jones v. United States, 362 U. S. 257 (1960); Silverman v. United States, 365 U. S. 505 (1961); Lanza v. New York, 370 U. S. 139 (1962).

It is, of course, true that the opinion in On Lee drew some support from a brief additional assertion that “eavesdropping on a conversation, with the connivance of one of the parties” raises no Fourth Amendment problem. 343 U. S., at 754. But surely it is a misreading of that opinion to view this unelaborated assertion as a wholly independent ground for decision. At the very least, this *775rationale needs substantial buttressing if it is to persist in our constitutional jurisprudence after the decisions I discuss below. Indeed, the plurality opinion in the present case, in greatly elaborating the point, tacitly recognizes' the analytic inability of this bare hypothesis to support a rule of law so profoundly important to the proper administration of justice. Moreover, if this was the true rationale of On Lee from the outset, it is difficult to see the relevance of Desist to the resolution of the instant case, for Katz surely does not speak directly to the continued viability of that ground for decision. See Katz v. United States, 389 U. S., at 363 n. (White, J., concurring).

By 1963, when we decided Lopez v. United States, 373 U. S. 427, four members of the Court were prepared to pronounce On Lee and Olmstead v. United States, 277 U. S. 438 (1928), dead.8 The pyre,- they reasoned, had been stoked by decisions like Wong Sun v. United States, 371 U. S. 471 (1963), which, on the one hand, expressly brought verbal communication within the sweep of the Fourth Amendment,9 and, on the other, re*776inforced our Silverman and Jones decisions which “refused to crowd the Fourth Amendment into the mold of local property law,” 373 U. S., at 460 (Brennan, J., dissenting).

Although the Court’s decision in Lopez is cited by the Government as a reaffirmation of On Lee, it can hardly be thought to have nurtured the questionable rationale of that decision or its much-criticized ancestor, Olmstead. To the discerning lawyer Lopez could only give pause, not comfort. While the majority opinion, of which I was the author, declined to follow the course favored by the dissenting and concurring Justices by sounding the death knell for Olmstead and On Lee, our holding, despite an allusion to the absence of “an unlawful ... invasion of a constitutionally protected area,” 373 U. S., at 438-439, was bottomed on two premises: the corroborative use that was made of the tape recordings, which increased reliability in the factfinding process, and the absence of a “risk” not fairly assumed by petitioner. The tape recording was made by a participant in the conversation and the opinion emphasized this absence of a third-party intrusion, expressly noting that there was no “electronic eavesdropping on a private conversation which government agents could not otherwise have overheard.” 373 U. S., at 440.10 As I point out in Part III *777of this opinion, it is one thing to subject the average citizen to the risk that participants in a conversation with him will subsequently divulge its contents to another, but quite a different matter to foist upon him the risk that unknown third parties may be simultaneously listening in.

While Lopez cited On Lee without disavowal of its holding, 373 U. S., at 438, it is entirely accurate to say that we did not there reaffirm it.11 No decision since Lopez gives a breath of life to the reasoning that led to the On Lee and Olmstead results, and it required little clairvoyance to predict the demise of the basic rationale of On Lee and Olmstead foreshadowed by our subsequent opinions in Osborn v. United States, 385 U. S. 323 (1966), and Berger v. New York, 388 U. S. 41 (1967).

Only three years after Lopez, Mr. Justice Stewart writing for the Court in Osborn v. United States, supra, expressly abjured reliance on Lopez and, instead, approved identical conduct based on the “circumstances under which the tape recording was obtained in [that] case,” facts that involved “using [a recorder] under the most precise and discriminate circumstances, circumstances which fully met the 'requirement of particularity' *778which the dissenting opinion in Lopez found necessary.” Osborn v. United States, 385 U. S., at 327, 329.12

Since Osborn our decisions have shown no tolerance for the old dividing lines resting, as they did, on fiction and common-law distinctions without sound policy justification in the realm of values protected by the Fourth Amendment. Thus, in abolishing the “mere evidence rule” we announced that “the principal object of the Fourth Amendment is the protection of privacy rather than property,” and once again noted the trend to discard “fictional and procedural barriers rested on property concepts.” Warden v. Hayden, 387 U. S. 294, 304 (1967). That same Term the Court demonstrated the new flexibility in Fourth Amendment doctrine when it held that the warrant protections would be applied to administrative searches. Camara v. Municipal Court, 387 U. S. 523 (1967).

Certainly if Osborn, Warden, and Camara did not plainly draw into question the vigor of earlier precedents, Berger v. New York, 388 U. S. 41, did, and expunged any remnants of former doctrine which might have been *779thought to have survived Osborn and Warden. 13 There, the Court, following a path opened by Mr. Justice Bran-déis’ dissent in Olmstead, and smoothed in Osborn and Camara, expressed concern about scientific developments that have put within the reach of the Government the private communications of “anyone in almost any given situation,” 388 U. S., at 47; it left no doubt that, as a general principle, electronic eavesdropping was an invasion of privacy and that the Fourth Amendment prohibited unsupervised “bugging.” Disturbed by the extent of intrusion which “[b]y its very nature ... is broad in scope,” and noting that “[f]ew threats to liberty exist which are greater than that posed by the use of eavesdropping devices,” id., at 63, the Court brought to life the principle of reasonableness adumbrated in Osborn. Mr. Justice Clark, writing for the majority, reiterated the new approach:

“[T]he ‘indiscriminate use of such [bugging] devices in law enforcement raises grave constitutional questions under the Fourth and Fifth Amendments,’ and imposes ‘a heavier responsibility on this Court in its supervision of the fairness of procedures ....’” 388 U. S., at 56, quoting from Osborn v. United States, 385 U. S. 323, 329 n. 7.

Nor did the Court waver in resolve in the face of respondent’s dire prediction that “neither a warrant nor a statute authorizing eavesdropping can be drawn so as to meet the Fourth Amendment’s requirements.” 14 It *780was said that “ [i] f that be true then the ‘fruits’ of eavesdropping devices are barred under the Amendment.” 388 U. S., at 63.15

If Berger did not flatly sound a dirge for Olmstead, it articulated principles that led Mr. Justice Douglas, by way of concurrence, to comment on its quiet burial. 388 U. S., at 64. While it was left to Katz to perform the last rites, that decision inevitably followed from Osborn and Berger. The Berger majority’s affirmative citation of On Lee for the principle that “under specific conditions and circumstances” eavesdropping may be lawful, 388 U. S., at 63, serves only to underscore the emerging operative assumptions: that the particular circumstances of each case will be scrutinized to the end of ascertaining the reasonableness of the search, and that will depend in large measure on whether prior judicial authorization, based on a particularized showing, has been obtained. Katz v. United States, supra.

Viewed in perspective, then, Katz added no new dimension to the law. At most it was a formal dispatch of Olmstead and the notion that such problems may usefully be resolved in the light of trespass doctrine, and, of course, it freed from speculation what was already evident, that On Lee was completely open to question.

B

But the decisions of this Court since On Lee do more than demonstrate that the doctrine of that case is wholly open for reconsideration, and has been since well before Katz was decided. They also establish sound general principles for application of the Fourth Amendment that were either dimly perceived or not fully worked out *781at the time of On Lee. I have already traced some of these principles in Part II-A, supra: that verbal communication is protected by the Fourth Amendment, that the reasonableness of a search does not depend on the presence or absence of a trespass, and that the Fourth Amendment is principally concerned with protecting interests of privacy, rather than property rights.

Especially when other recent Fourth Amendment decisions, not otherwise so immediately relevant, are read with those already discussed, the primacy of an additional general principle becomes equally evident: official investigatory action that impinges on privacy must typically, in order to be constitutionally permissible, be subjected to the warrant requirement. Particularly significant in this regard are Camara v. Municipal Court, 387 U. S. 523 (1967); Terry v. Ohio, 392 U. S. 1 (1968), and Chimel v. California, 395 U. S. 752 (1969).

In Camara the Court brought under the Fourth Amendment administrative searches that had once been thought to be without its sweep. In doing so the opinion emphasized' the desirability of establishing in advance those circumstances that justified the intrusion into a home and submitting them for review to an independent assessor,16 principles that this Court has always deemed to be at the core of Fourth Amendment protections.17 *782In bringing such searches within the ambit of the warrant requirement, Camara rejected the notion that the “less hostile” nature of the search relegated this invasion of privacy to the “periphery” of Fourth Amendment concerns. 387 U. S., at 530. The central consideration was, the Court concluded, that these administrative actions, no less than the typical search, involved government officials in an invasion of privacy, and that it was against the possible arbitrariness of invasion that the Fourth Amendment with its warrant machinery was meant to guard. Berger and Katz built, as noted earlier, on Osborn v. United States, supra, and Camara, and gave further expression to the principle.18 It was not enough that government agents acted with restraint, for reasonableness must in the first instance be judged in a detached realm.19

*783The scope and meaning of the rule have emerged with even greater clarity by virtue of our holdings setting the boundaries for the exceptions. Recently, in Chimel v. California, 395 U. S. 752 (1969), we reiterated the importance of the prior independent determination of a neutral magistrate and underscored its centrality to the reasonableness requirement of the Fourth Amendment, and abandoned the holdings of Harris v. United States, 331 U. S. 145 (1947), and United States v. Rabinowitz, 339 U. S. 56 (1950). We were concerned by the breadth of searches occasioned by the Rabinowitz rule which frequently proved to be an invitation to a hunting expedition. Searches incident to arrest, we held, must be confined to a locus no greater than necessary to prevent injury to the arresting officer or destruction of evidence. 395 U. S., at 763, 767; cf. Terry v. Ohio, 392 U. S. 1 (1968).

To complete the tapestry, the strands of doctrine reflected in the search cases must be interwoven with the Court’s other contemporary holdings. Most signifi*784cant are Terry v. Ohio, supra, and Davis v. Mississippi, 394 U. S. 721 (1969), which were also harbingers of the new thrust in Fourth Amendment doctrine. There the Court rejected the contention that only an arrest triggered the “incident-to-arrest” exception to the warrant requirement of the Fourth Amendment, and held that any restraint of the person, however brief and however labeled, was subject to a reasonableness examination. 392 U. S., at 19. The controlling principle is “to recognize that the Fourth Amendment governs all intrusions by agents of the public upon personal security, and to make the scope of the particular intrusion, in light of all the exigencies of the case, a central element in the analysis of reasonableness.” 392 U. S., at 18 n. 15. See also Davis v. Mississippi, 394 U. S., at 727.20

Ill

A

That the foundations of On Lee have been destroyed does not, of course, mean that its result can no longer stand. Indeed, the plurality opinion today fastens upon our decisions in Lopez, Lewis v. United States, 385 U. S. 206 (1966), and Hoffa v. United States, 385 U. S. 293 (1966), to resist the undercurrents of more recent cases emphasizing the warrant procedure as a safeguard to privacy. But this category provides insufficient support. In each of these cases the risk the general populace faced was different from that surfaced by the instant case. No surreptitious third ear was present, and in each opinion that fact was carefully noted.

*785In Lewis, a federal agent posing as a potential purchaser of narcotics gained access to petitioner’s home and there consummated an illegal sale, the fruits of which were admitted at trial along with the testimony of the agent. Chief Justice Warren, writing for the majority, expressly distinguished the third-party overhearing involved, by way of example, in a case like Silverman v. United States, supra, noting that “there, the conduct proscribed was that of eavesdroppers, unknown and unwanted intruders who furtively listened to conversations occurring in the privacy of a house.” 385 U. S., at 212. Similarly in Hoff a, Mr. Justice Stewart took care to mention that “surreptitious” monitoring was not there before the Court, and so too in Lopez, supra.

The plurality opinion seeks to erase the crucial distinction between the facts before us and these holdings by the following reasoning: if A can relay verbally what is revealed to him by B (as in Lewis and Hoff a), or record and later divulge it (as in Lopez), what difference does it make if A conspires with another to betray B by contemporaneously transmitting to the other all that is said? The contention is, in essence, an argument that the distinction between third-party monitoring and other undercover techniques is one of form and not substance. The force of the contention depends on the evaluation of two separable but intertwined assumptions: first, that there is no greater invasion of privacy in the third-party situation, and, second, that uncontrolled consensual surveillance in an electronic age is a tolerable technique of law enforcement, given the values and goals of our political system.21

*786The first of these assumptions takes as a point of departure the so-called “risk analysis” approach of Lewis, and Lopez, and to a lesser extent On Lee, or the expectations approach of Katz. See discussion in Part II, supra. While these formulations represent an advance over the unsophisticated trespass analysis of the common law, they too have their limitations and can, ultimately, lead to the substitution of words for analysis.22 The analysis must, in my view, transcend the search for subjective expectations or legal attribution of assumptions of risk. Our expectations, and the risks we assume, are in large part reflections of laws that translate into rules the customs and values of the past and present.

Since it is the task of the law to form and project, as well as mirror and reflect, we should not, as judges, merely recite the expectations and risks without examining the desirability of saddling them upon society. The critical question, therefore, is whether under our system of government, as reflected in the Constitution, we should impose on our citizens the risks of the electronic listener or observer without at least the protection of a warrant requirement.

This question must, in my view, be answered by assessing the nature of a particular practice and the likely extent of its impact on the individual’s sense of security balanced against the utility of the conduct as a technique of law enforcement. For those more extensive intrusions that significantly jeopardize the sense of security which is the paramount concern of Fourth Amendment liberties, I am of the view that more than self-restraint by law enforcement officials is required and at the least warrants *787should be necessary. Cf. Terry v. Ohio, supra; Davis v. Mississippi, supra.

B

The impact of the practice of third-party bugging, must, I think, be considered such as to undermine that confidence and sense of security in dealing with one another that is characteristic of individual relationships between citizens in a free society. It goes beyond the impact on privacy occasioned by the ordinary type of “informer” investigation upheld in Lewis and Hoff a. The argument of the plurality opinion, to the effect that it is irrelevant whether secrets are revealed by the mere tattletale or the transistor, ignores the differences occasioned by third-party monitoring and recording which insures full and accurate disclosure of all that is said, free of the possibility of error and oversight that inheres in human reporting.

Authority is hardly required to support the proposition that words would be measured a good deal more carefully and communication inhibited if one suspected his conversations were being transmitted and transcribed. Were third-party bugging a prevalent practice, it might well smother that spontaneity — reflected in frivolous, impetuous, sacrilegious, and defiant discourse — that liberates daily life.23 Much off-hand exchange is easily for*788gotten and one may count on the obscurity of his remarks, protected by the very fact of a limited audience, and the likelihood that the listener will either overlook or forget what is said, as well as the listener’s inability to reformulate a conversation without having to contend with a documented record.24 All these values are sacrificed by *789a rule of law that permits official monitoring of private discourse limited only by the need to locate a willing assistant.

It matters little that consensual transmittals are less obnoxious than wholly clandestine eavesdrops. This was put forward as justification for the conduct in Boyd v. United States, 116 U. S. 616 (1886), where the Government relied on mitigating aspects of the conduct in question. The Court, speaking through Mr. Justice Bradley, declined to countenance literalism:

“Though the proceeding in question is divested of many of the aggravating incidents of actual search and seizure, yet, as before said, it contains their substance and essence, and effects their substantial purpose. 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.” 116 U. S., at 635.

Finally, it is too easy to forget — and, hence, too often forgotten — that the issue here is whether to interpose a search warrant procedure between law enforcement agencies engaging in electronic eavesdropping and the public generally. By casting its “risk analysis” solely in terms of the expectations and risks that “wrongdoers” or “one contemplating illegal activities” ought to bear, the plurality opinion, I think, misses the mark entirely. On Lee does not simply mandate that criminals must daily run the risk of unknown eavesdroppers prying into their private affairs; it subjects each and every law-abiding member of society to that risk. The very purpose of interposing the Fourth Amendment warrant requirement is to redistribute the privacy risks throughout society in a way that produces the results the plurality opinion ascribes to the On Lee rule. Abolition of On Lee would *790not end electronic eavesdropping. It would prevent public officials from engaging in that practice unless they first had probable cause to suspect an individual of involvement in illegal activities and had tested their version of the facts before a detached judicial officer. The interest On Lee fails to protect is the expectation of the ordinary citizen, who has never engaged in illegal conduct in his life, that he may carry on his private discourse freely, openly, and spontaneously without measuring his every word against the connotations it might carry when instantaneously heard by others unknown to him and unfamiliar with his situation or analyzed in a cold, formal record played days, months, or years after the conversation. Interposition of a warrant requirement is designed not to shield “wrongdoers,” but to secure a measure of privacy and a sense of personal security throughout our society.

The Fourth Amendment does, of course, leave room for the employment of modern technology in criminal law enforcement, but in the stream of current developments in Fourth Amendment law I think it must be held that third-party electronic monitoring, subject only to the self-restraint of law enforcement officials, has no place in our society.

IV

I reach these conclusions notwithstanding seemingly contrary views espoused by both Congress and an American Bar Association study group.25 Both the ABA *791study and Title III of the Omnibus Crime Control and Safe Streets Act of 1968, 82 Stat. 212, 18 U. S. C. § 2510 et seq. (1964 ed., Supp. V), appear to reflect little more than this Court’s prior decisions. Indeed, the comprehensive provisions of Title III are evidence of the extent of congressional concern with the impact of electronic surveillance on the right to privacy. This concern is further manifested in the introductory section of the Senate Committee Report.26 Although §2511 (2) (c) exempts consensual and participant monitoring by law enforcement agents from the general prohibitions against surveillance without prior judicial authorization and makes the fruits admissible in court, see § 2515, congressional malaise with such conduct is evidenced by the contrastingly limited endorsement of consensual surveillance carried out by private individuals.27 While individual Congressmen expressed concern about and criticized the provisions for unsupervised consensual electronic surveillance contained in § 2511,28 the Senate Committee Report comment, to the effect that “[i]t (§ 2511 (2)(c)] largely reflects existing law,” S. Rep. No. 1097, 90th Cong., 2d Sess., 93-94 (1968), followed by citations to On Lee and Lopez, 29 strongly suggests that the provisions represent not intractable approval of these practices, but rather an intention to adopt these holdings and to leave to the courts the task of determining their viability in *792light of later holdings such as Berger, Osborn, and Katz. 30

I find in neither the ABA study nor Title III any justification for ignoring the identifiable difference— albeit an elusive one in the present state of knowledge- — • between the impact on privacy of single-party informer bugging and third-party bugging, which in my opinion justifies drawing the constitutional line at this juncture between the two as regards the necessity for obtaining a warrant. Recognition of this difference is, at the very least, necessary to preserve the openness which is at the core of our traditions and is secure only in a society that tolerates official invasion of privacy simply in circumscribed situations.

The Fourth Amendment protects these traditions, and places limitations on the means and circumstances by which the Government may collect information about its citizens by intruding into their personal lives. The *793spirit of the principle is captured by the oft-quoted language of Boyd v. United States, 116 U. S., at 630:

“The principles laid down in this opinion i[ speaking of Entick v. Carrington, 19 How. St. Tr. 1029 (1765)] affect the very essence of constitutional liberty and security. They reach farther than the concrete form of the case then before the court, with its adventitious circumstances; they apply to all invasions on the part of the government and its employes of the sanctity of a man’s home and the privacies of life. It is not the breaking of his doors, and the rummaging of his drawers, that constitutes the essence of the offence; but it is the invasion of his indefeasible right of personal security . . . .”

What this means is that the burden of guarding privacy in a free society should not be on its citizens; it is the Government that must justify its need to electronically eavesdrop.

V

Not content to rest upon the proposition that On Lee remains sound law, the plurality opinion would also hold that the Court of Appeals erred further in disposing “of this case based on its understanding of the principles announced in the Katz case,” ante, at 754, because Desist v. United States, 394 U. S. 244 (1969), held that Katz governed only governmental conduct occurring after the decision in Katz. It is difficult to know where to begin to analyze such a truly extraordinary assertion respecting the operation of the judicial process.

Because this case is here on direct review, even were the issues squarely controlled by Katz, I would unhesitatingly apply here the rule there adopted, for the reasons first expressed in my dissent in Desist, 394 U. S., at 256, and elaborated in my separate opinion in Mackey *794v. United States (and companion cases), ante, p. 675. I see no purpose in repeating at this point the analysis I set forth in those opinions. Suffice it to say that, in Desist, I went to some length to point out, by discussing a hypothetical proposition, that the failure to apply any new decision by this Court to cases which had not yet run their course on direct review was inconsistent with the case-by-case approach to constitutional decision and with the proper relationship of this Court to the lower federal courts. In particular, I noted that the logic of Desist suggested that it would constitute error for a lower federal court to adopt a new constitutional rule which this Court subsequently approved. 394 U. S., at 259. Today’s opinion stands as eloquent evidence of that defect.

Indeed, I find this decision even more troubling than Desist. For the errors of Desist are not merely repeated here; they are plainly compounded. Upon the plurality opinion’s own analysis of the instant case, it is clear that Katz has no direct relevance to the present viability of On Lee. “Katz involved no revelation to the Government by a party to conversations with the defendant nor did the Court indicate in any way that a defendant has a justifiable and constitutionally protected expectation that a person with whom he is conversing will not then or later reveal the conversation to the police.” Ante, at 749. As I have already shown, one need not cite Katz to demonstrate the inability of On Lee to survive recent developments without at least substantial reformulation. To hold, then, that a mere citation of Katz, or drawing upon the philosophical underpinnings of that case in order to employ a general constitutional approach in tune with that of the decisions of this Court, conflicts with the holding of Desist is to let this obsession with prospectivity run riot.

*795Apparently Desist is now to be understood as holding that all lower federal courts are disabled from adjudicating on their merits all allegations of Fourth Amendment error not squarely supported by a prior decision of this Court. If so, one wonders what purpose is served by providing intermediate appellate review of constitutional issues in the federal criminal process. We must not forget that this Court is not the only tribunal in the entire federal system charged with a responsibility for the nurture and development of the Fourth Amendment. It is one thing to disable all federal courts, including this Court, from applying the settled law of the land to cases and controversies before them — as Desist does with Katz — and at least another giant step backward to preclude lower courts from resolving wholly disparate controversies in the light of constitutional principles. Can it be seriously contended, as the plurality opinion necessarily implies, that the Court of Appeals should not be reversed today on these alternative grounds had it simply omitted to discuss Katz? To force lower federal courts to adjudicate controversies either mechanistically or disingenuously is for me indefensible. Yet this is precisely what the plurality opinion does with its assertion that it is error for lower courts to “dispose” of a case based on their “understanding of the principles announced” in Katz for the next year or so.

I would hold that On Lee is no longer good law and affirm the judgment below.

Mr. Justice Marshall,

dissenting.

I am convinced that the correct view of the Fourth Amendment in the area of electronic surveillance is one that brings the safeguards of the warrant requirement to bear on the investigatory activity involved in this case. In this regard I agree with the dissents of Mr. Justice *796Douglas and Me. Justice Harlan. In short, I believe that On Lee v. United States, 343 U. S. 747 (1952), cannot be considered viable in light of the constitutional principles articulated in Katz v. United States, 389 U. S. 347 (1967), and other cases. And for reasons expressed by Mr. Justice Fortas in dissent in Desist v. United States, 394 U. S. 244, 269 (1969), I do not think we should feel constrained to employ a discarded theory of the Fourth Amendment in evaluating the governmental intrusions challenged here.

*37Justice White

delivered the opinion of the Court.

The issue here is whether the Fourth Amendment prohibits the warrantless search and seizure of garbage left for collection outside the curtilage of a home. We conclude, in accordance with the vast majority of lower courts that have addressed the issue, that it does not.

h — 1

In early 1984, Investigator Jenny Stracner of the Laguna Beach Police Department received information indicating that respondent Greenwood might be engaged in narcotics trafficking. Stracner learned that a criminal suspect had informed a federal drug enforcement agent in February 1984 that a truck filled with illegal drugs was en route to the Laguna Beach address at which Greenwood resided. In addition, a neighbor complained of heavy vehicular traffic late at night in front of Greenwood’s single-family home. The neighbor reported that the vehicles remained at Greenwood’s house for only a few minutes.

Stracner sought to investigate this information by conducting a surveillance of Greenwood’s home. She observed several vehicles make brief stops at the house during the late-night and early morning hours, and she followed a truck from the house to a residence that had previously been under investigation as a narcotics-trafficking location.

On April 6, 1984, Stracner asked the neighborhood’s regular trash collector to pick up the plastic garbage bags that Greenwood had left on the curb in front of his house and to turn the bags over to her without mixing their contents with garbage from other houses. The trash collector cleaned his truck bin of other refuse, collected the garbage bags from the street in front of Greenwood’s house, and turned the bags over to Stracner. The officer searched through the rubbish *38and found items indicative of narcotics use. She recited the information that she had gleaned from the trash search in an affidavit in support of a warrant to search Greenwood’s home.

Police officers encountered both respondents at the house later that day when they arrived to execute the warrant. The police discovered quantities of cocaine and hashish during their search of the house. Respondents were arrested on felony narcotics charges. They subsequently posted bail.

The police continued to receive reports of many late-night visitors to the Greenwood house. On May 4, Investigator Robert Rahaeuser obtained Greenwood’s garbage from the regular trash collector in the same manner as had Stracner. The garbage again contained evidence of narcotics use.

Rahaeuser secured another search warrant for Greenwood’s home based on the information from the second trash search. The police found more narcotics and evidence of narcotics trafficking when they executed the warrant. Greenwood was again arrested.

The Superior Court dismissed the charges against respondents on the authority of People v. Krivda, 5 Cal. 3d 357, 486 P. 2d 1262 (1971), which held that warrantless trash searches violate the Fourth Amendment and the California Constitution. The court found that the police would not have had probable cause to search the Greenwood home without the evidence obtained from the trash searches.

The Court of Appeal affirmed. 182 Cal. App. 3d 729, 227 Cal. Rptr. 539 (1986). The court noted at the outset that the fruits of warrantless trash searches could no longer be suppressed if Krivda were based only on the California Constitution, because since 1982 the State has barred the suppression of evidence seized in violation of California law but not federal law. See Cal. Const., Art. I, § 28(d); In re Lance W., 37 Cal. 3d 873, 694 P. 2d 744 (1985). But Krivda, a decision binding on the Court of Appeal, also held that the fruits of warrantless trash searches were to be excluded under federal *39law. Hence, the Superior Court was correct in dismissing the charges against respondents. 182 Cal. App. 3d, at 735, 227 Cal. Rptr, at 542.1

The California Supreme Court denied the State’s petition for review of the Court of Appeal’s decision. We granted certiorari, 483 U. S. 1019, and now reverse.

) — I I — C

The warrantless search and seizure of the garbage bags left at the curb outside the Greenwood house would violate the Fourth Amendment only if respondents manifested a subjective expectation of privacy in their garbage that society accepts as objectively reasonable. O’Connor v. Ortega, 480 U. S. 709, 715 (1987); California v. Ciraolo, 476 U. S. 207, 211 (1986); Oliver v. United States, 466 U. S. 170, 177 (1984); Katz v. United States, 389 U. S. 347, 361 (1967) (Harlan, J., concurring). Respondents do not disagree with this standard.

They assert, however, that they had, and exhibited, an expectation of privacy with respect to the trash that was searched by the police: The trash, which was placed on the street for collection at a fixed time, was contained in opaque plastic bags, which the garbage collector was expected to pick up, mingle with the trash of others, and deposit at the garbage dump. The trash was only temporarily on the street, and there was little likelihood that it would be inspected by anyone.

It may well be that respondents did not expect that the contents of their garbage bags would become known to the police or other members of the public. An expectation of privacy does not give rise to Fourth Amendment protection, *40however, unless society is prepared to accept that expectation as objectively reasonable.

Here, we conclude that respondents exposed their garbage to the public sufficiently to defeat their claim to Fourth Amendment protection. It is common knowledge that plastic garbage bags left on or at the side of a public street are readily accessible to animals,2 children, scavengers,3 snoops,4 and other members of the public. See Krivda, supra, at 367, 486 P. 2d, at 1269. Moreover, respondents placed their refuse at the curb for the express purpose of conveying it to a third party, the trash collector, who might himself have sorted through respondents’ trash or permitted others, such as the police, to do so. Accordingly, having deposited their garbage “in an area particularly suited for *41public inspection and, in a manner of speaking, public consumption, for the express purpose of having strangers take it,” United States v. Reicherter, 647 F. 2d 397, 399 (CA3 1981), respondents could have had no reasonable expectation of privacy in the inculpatory items that they discarded.

Furthermore, as we have held, the police cannot reasonably be expected to avert their eyes from evidence of criminal activity that could have been observed by any member of the public. Hence, “[w]hat a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection.” Katz v. United States, supra, at 351. We held in Smith v. Maryland, 442 U. S. 735 (1979), for example, that the police did not violate the Fourth Amendment by causing a pen register to be installed at the telephone company’s offices to record the telephone numbers dialed by a criminal suspect. An individual has no legitimate expectation of privacy in the numbers dialed on his telephone, we reasoned, because he voluntarily conveys those numbers to the telephone company when he uses the telephone. Again, we observed that “a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties.” Id., at 743-744.

Similarly, we held in California v. Ciraolo, supra, that the police were not required by the Fourth Amendment to obtain a warrant before conducting surveillance of the respondent’s fenced backyard from a private plane flying at an altitude of 1,000 feet. We concluded that the respondent’s expectation that his yard was protected from such surveillance was unreasonable because “[a]ny member of the public flying in this airspace who glanced down could have seen everything that these officers observed.” Id., at 213-214.

Our conclusion that society would not accept as reasonable respondents’ claim to an expectation of privacy in trash left for collection in an area accessible to the public is reinforced by the unanimous rejection of similar claims by the Federal Courts of Appeals. See United States v. Dela Espriella, *42781 F. 2d 1432, 1437 (CA9 1986); United States v. O’Bryant, 775 F. 2d 1528, 1533-1534 (CA11 1985); United States v. Michaels, 726 F. 2d 1307, 1312-1313 (CA8), cert. denied, 469 U. S. 820 (1984); United States v. Kramer, 711 F. 2d 789, 791-794 (CA7), cert. denied, 464 U. S. 962 (1983); United States v. Terry, 702 F. 2d 299, 308-309 (CA2), cert. denied sub nom. Williams v. United States, 461 U. S. 931 (1983); United States v. Reicherter, supra, at 399; United States v. Vahalik, 606 F. 2d 99, 100-101 (CA5 1979) (per curiam), cert. denied, 444 U. S. 1081 (1980); United States v. Crowell, 586 F. 2d 1020, 1025 (CA4 1978), cert. denied, 440 U. S. 959 (1979); Magda v. Benson, 536 F. 2d 111, 112-113 (CA6 1976) (per curiam); United States v. Mustone, 469 F. 2d 970, 972-974 (CA1 1972). In United States v. Thornton, 241 U. S. App. D. C. 46, 56, and n. 11, 746 F. 2d 39, 49, and n. 11 (1984), the court observed that “the overwhelming weight of authority rejects the proposition that a reasonable expectation of privacy exists with respect to trash discarded outside the home and the curtilege [sic] thereof.” In addition, of those state appellate courts that have considered the issue, the vast majority have held that the police may conduct war-rantless searches and seizures of garbage discarded in public areas. See Commonwealth v. Chappee, 397 Mass. 508, 512-513, 492 N. E. 2d 719, 721-722 (1986); Cooks v. State, 699 P. 2d 653, 656 (Okla. Crim.), cert, denied, 474 U. S. 935 (1985); State v. Stevens, 123 Wis. 2d 303, 314-317, 367 N. W. 2d 788, 794-797, cert. denied, 474 U. S. 852 (1985); State v. Ronngren, 361 N. W. 2d 224, 228-230 (N. D. 1985); State v. Brown, 20 Ohio App. 3d 36, 37-38, 484 N. E. 2d 215, 217-218 (1984); State v. Oquist, 327 N. W. 2d 587 (Minn. 1982); People v. Whotte, 113 Mich. App. 12, 317 N. W. 2d 266 (1982); Commonwealth v. Minton, 288 Pa. Super. 381, 391, 432 A. 2d 212, 217 (1981); State v. Schultz, 388 So. 2d 1326 (Fla. App. 1980); People v. Huddleston, 38 Ill. App. 3d 277, 347 N. E. 2d 76 (1976); Willis v. State, 518 S. W. 2d 247, 249 (Tex. Crim. App. 1975); Smith v. State, 510 P. 2d 793 (Alaska), cert. denied, *43414 U. S. 1086 (1973); State v. Fassler, 108 Ariz. 586, 592-593, 503 P. 2d 807, 813-814 (1972); Croker v. State, 477 P. 2d 122, 125-126 (Wyo. 1970); State v. Purvis, 249 Ore. 404, 411, 438 P. 2d 1002, 1005 (1968). But see State v. Tanaka, 67 Haw. 658, 701 P. 2d 1274 (1985); People v. Krivda, 5 Cal. 3d 357, 486 P. 2d 1262 (1971).5

Ill

We reject respondent Greenwood’s alternative argument for affirmance: that his expectation of privacy in his garbage should be deemed reasonable as a matter of federal constitutional law because the warrantless search and seizure of his garbage was impermissible as a matter of California law. He urges that the state-law right of Californians to privacy in their garbage, announced by the California Supreme Court in Krivda, supra, survived the subsequent state constitutional amendment eliminating the suppression remedy as a means of enforcing that right. See In re Lance W., 37 Cal. 3d, at 886-887, 694 P. 2d, at 752-753. Hence, he argues that the Fourth Amendment should itself vindicate that right.

Individual States may surely construe their own constitutions as imposing more stringent constraints on police conduct than does the Federal Constitution. We have never intimated, however, that whether or not a search is reasonable within the meaning of the Fourth Amendment depends on the law of the particular State in which the search occurs. We have emphasized instead that the Fourth Amendment analysis must turn on such factors as “our societal understanding that certain areas deserve the most scrupulous protection from government invasion.” Oliver v. United States, 466 U. S., at 178 (emphasis added). See also Rakas v. Illinois, 439 U. S. 128, 143-144, n. 12 (1978). We have already concluded that society as a whole possesses no such under*44standing with regard to garbage left for collection at the side of a public street. Respondent’s argument is no less than a suggestion that concepts of privacy under the laws of each State are to determine the reach of the Fourth Amendment. We do not accept this submission.

> h — I

Greenwood finally urges as an additional ground for affirmance that the California constitutional amendment eliminating the exclusionary rule for evidence seized in violation of state but not federal law violates the Due Process Clause of the Fourteenth Amendment. In his view, having recognized a state-law right to be free from warrantless searches of garbage, California may not under the Due Process Clause deprive its citizens of what he describes as “the only effective deterrent” to violations of this right. Greenwood concedes that no direct support for his position can be found in the decisions of this Court. He relies instead on cases holding that individuals are entitled to certain procedural protections before they can be deprived of a liberty or property interest created by state law. See Hewitt v. Helms, 459 U. S. 460 (1983); Vitek v. Jones, 445 U. S. 480 (1980).

We see no merit in Greenwood’s position. California could amend its Constitution to negate the holding in Krivda that state law forbids warrantless searches of trash. We are convinced that the State may likewise eliminate the exclusionary rule as a remedy for violations of that right. At the federal level, we have not required that evidence obtained in violation of the Fourth Amendment be suppressed in all circumstances. See, e. g., United States v. Leon, 468 U. S. 897 (1984); United States v. Janis, 428 U. S. 433 (1976); United States v. Calandra, 414 U. S. 338 (1974). Rather, our decisions concerning the scope of the Fourth Amendment exclusionary rule have balanced the benefits of détérring police misconduct against the costs of excluding reliable evidence of criminal activity. See Leon, 468 U. S., at 908-913. We *45have declined to apply the exclusionary rule indiscriminately “when law enforcement officers have acted in objective good faith or their transgressions have been minor,” because “the magnitude of the benefit conferred on . . . guilty defendants [in such circumstances] offends basic concepts of the criminal justice system.” Id., at 908 (citing Stone v. Powell, 428 U. S. 465, 490 (1976)).

The States are not foreclosed by the Due Process Clause from using a similar balancing approach to delineate the scope of their own exclusionary rules. Hence, the people of California could permissibly conclude that the benefits of excluding relevant evidence of criminal activity do not outweigh the costs when the police conduct at issue does not violate federal law.

V

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

It is so ordered.

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

Justice Brennan,

with whom Justice Marshall joins, dissenting.

Every week for two months, and at least once more a month later, the Laguna Beach police clawed through the trash that respondent Greenwood left in opaque, sealed bags on the curb outside his home. Record 113. Complete strangers minutely scrutinized their bounty, undoubtedly dredging up intimate details of Greenwood’s private life and habits. The intrusions proceeded without a warrant, and no court before or since has concluded that the police acted on probable cause to believe Greenwood was engaged in any criminal activity.

Scrutiny of another’s trash is contrary to commonly accepted notions of civilized behavior. I suspect, therefore, *46that members of our society will be shocked to learn that the Court, the ultimate guarantor of liberty, deems unreasonable our expectation that the aspects of our private lives that are concealed safely in a trash bag will not become public.

I

"A container which can support a reasonable expectation of privacy may not be searched, even on probable cause, without a. warrant.” United States v. Jacobsen, 466 U. S. 109, 120, n. 17 (1984) (citations omitted). Thus, as the Court observes, if Greenwood had a reasonable expectation that the contents of the bags that he placed on the curb would remain private, the warrantless search of those bags violated the Fourth Amendment. Ante, at 39.

The Framers of the Fourth Amendment understood that “unreasonable searches” of “paper[s] and effects” — no less than “unreasonable searches” of “person[s] and houses” — infringe privacy. As early as 1878, this Court acknowledged that the contents of “[l]etters and sealed packages ... in the mail are as fully guarded from examination and inspection . . . as if they were retained by the parties forwarding them in their own domiciles.” Ex parte Jackson, 96 U. S. 727, 733. In short, so long as a package is “closed against inspection,” the Fourth Amendment protects its contents, “wherever they may be,” and the police must obtain a warrant to search it just “as is required when papers are subjected to search in one’s own household.” Jbid. Accord, United States v. Van Leeuwen, 397 U. S. 249 (1970).

With the emergence of the reasonable-expectation-of-privacy analysis, see Katz v. United States, 389 U. S. 347, 361 (1967) (Harlan, J., concurring); Smith v. Maryland, 442 U. S. 735, 740 (1979), we have reaffirmed this fundamental principle. In Robbins v. California, 453 U. S. 420 (1981), for example, Justice Stewart, writing for a plurality of four, pronounced that “unless the container is such that its contents may be said to be in plain view, those contents are fully *47protected by the Fourth Amendment,” id., at 427, and soundly rejected any distinction for Fourth Amendment purposes among various opaque, sealed containers:

“[E]ven if one wished to import such a distinction into the Fourth Amendment, it is difficult if not impossible to perceive any objective criteria by which that task might be accomplished. What one person may put into a suitcase, another may put into a paper bag. . . . And ... no court, no constable, no citizen, can sensibly be asked to distinguish the relative ‘privacy interests’ in a closed suitcase, briefcase, portfolio, duffelbag, or box.” Id., at 426-427.

See also id., at 428 (expectation of privacy attaches to any container unless it “so clearly announced] its contents, whether by its distinctive configuration, its transparency,' or otherwise, that its contents are obvious to an observer”). With only one exception, every Justice who wrote in that case eschewed any attempt to distinguish “worthy” from “unworthy” containers.1

More recently, in United States v. Ross, 456 U. S. 798 (1982), the Court, relying on the “virtually unanimous agree*48ment in Robbins . . . that a constitutional distinction between ‘worthy’ and ‘unworthy’ containers would be improper,” held that a distinction among “paper bags, locked trunks, lunch buckets, and orange crates” would be inconsistent with

“the central purpose of the Fourth Amendment. . . . [A] traveler who carries a toothbrush and a few articles of clothing in a paper bag or knotted scarf [may] claim an equal right to conceal his possessions from official inspection as the sophisticated executive with the locked atta-ché case.

“As Justice Stewart stated in Robbins, the Fourth Amendment provides protection to the owner of every container that conceals its contents from plain view.” Id., at 822-823 (emphasis added; footnote and citation omitted).

See also Jacobsen, supra, at 129 (opinion of White, J.).

Accordingly, we have found a reasonable expectation of privacy in the contents of a 200-pound “double-locked footlocker,” United States v. Chadwick, 433 U. S. 1, 11 (1977); a “comparatively small, unlocked suitcase,” Arkansas v. Sanders, 442 U. S. 753, 762, n. 9 (1979); a “totebag,” Robbins, 453 U. S., at 422; and “packages wrapped in green opaque plastic,” ibid. See also Ross, supra, at 801, 822-823 (suggesting that a warrant would have been required to search a “ ‘lunch-type’ brown paper bag” and a “zippered red leather pouch” had they not been found in an automobile); Jacobsen, supra, at 111, 114-115 (suggesting that a warrantless search of an “ordinary cardboard box wrapped in brown paper” would have violated the Fourth Amendment had a private party not already opened it).

Our precedent, therefore, leaves no room to doubt that had respondents been carrying their personal effects in opaque, sealed plastic bags — identical to the ones they placed on the curb — their privacy would have been protected from war-rantless police intrusion. So far as Fourth Amendment protection is concerned, opaque plastic bags are every bit as *49worthy as “packages wrapped in green opaque plastic” and “double-locked footlocker[s].” Cf. Robbins, supra, at 441 (Rehnquist, J., dissenting) (objecting to Court’s discovery of reasonable expectation of privacy in contents of “two plastic garbage bags”).

II

Respondents deserve no less protection just because Greenwood used the bags to discard rather than to transport his personal effects. Their contents are not inherently any less private, and Greenwood’s decision to discard them, at least in the manner in which he did, does not diminish his expectation of privacy.2

*50A trash bag, like any of the above-mentioned containers, “is a common repository for one’s personal effects” and, even more than many of them, is “therefore . . . inevitably associated with the expectation of privacy.” Sanders, supra, at 762 (citing Chadwick, supra, at 13). “[AJlmost every human activity ultimately manifests itself in waste products . . . .” Smith v. State, 510 P. 2d 793, 798 (Alaska), cert. denied, 414 U. S. 1086 (1973). See California v. Rooney, 483 U. S. 307, 320-321, n. 3 (1987) (White, J., dissenting) (renowned archaeologist Emil Haury once said, “[i]f you want to know what is really going on in a community, look at its garbage”) (quoted by W. Rathje, Archaeological Ethnography . . . Because Sometimes It Is Better to Give Than to Receive, in Explorations in Ethnoarchaeology 49, 54 (R. Gould ed. 1978)); Weberman, The Art of Garbage Analysis: You Are What You Throw Away, 76 Esquire 113 (1971) (analyzing trash of various celebrities and drawing conclusions about their private lives). A single bag of trash testifies eloquently to the eating, reading, and recreational habits of the person who produced it. A search of trash, like a search of the bedroom, can relate intimate details about sexual practices, health, and personal hygiene. Like rifling through desk drawers or intercepting phone calls, rummaging through trash can divulge the target’s financial and professional status, political affiliations and inclinations, private thoughts, personal relationships, and romantic interests. It cannot be doubted that a sealed trash bag harbors telling evidence of the “intimate activity associated with the ‘sanctity of a man’s home and the privacies of life,’” which the Fourth Amendment is designed *51to protect. Oliver v. United States, 466 U. S. 170, 180 (1984) (quoting Boyd v. United States, 116 U. S. 616, 630 (1886)). See also United States v. Dunn, 480 U. S. 294, 300 (1987).

The Court properly rejects the Státe’s attempt to distinguish trash searches from other searches on the theory that trash is abandoned and therefore not entitled to an expectation of privacy. As the author of the Court’s opinion observed last Term, a defendant’s “property interest [in trash] does not settle the matter for Fourth Amendment purposes, for the reach of the Fourth Amendment is not determined by state property law.” Rooney, supra, at 320 (White, J., dissenting). In evaluating the reasonableness of Greenwood’s expectation that his sealed trash bags would not be invaded, the Court has held that we must look to “understandings that are recognized and permitted by society.”3 Most of us, I believe, would be incensed to discover a meddler — whether a neighbor, a reporter, or a detective — scrutinizing our sealed trash containers to discover some detail of our personal lives. See State v. Schultz, 388 So. 2d 1326, 1331 (Fla. App. 1980) (Anstead, J., dissenting). That was, quite naturally, the reaction to the sole incident on which the Court bases its conclusion that “snoops” and the like defeat the expectation of privacy in trash. Ante, at 40, and n. 4. When a tabloid reporter examined then-Secretary of State *52Henry Kissinger’s trash and published his findings, Kissinger was “really revolted” by the intrusion and his wife suffered “grave anguish.” N. Y. Times, July 9, 1975, p. Al, col. 8. The public response roundly condemning the reporter demonstrates that society not only recognized those reactions as reasonable, but shared them as well. Commentators variously characterized his conduct as “a disgusting invasion of personal privacy,” Flieger, Investigative Trash, U. S. News & World Report, July 28, 1975, p. 72 (editor’s page); “indefensible ... as civilized behavior,” Washington Post, July 10, 1975, p. A18, col. 1 (editorial); and contrary to “the way decent people behave in relation to each other,” ibid.

Beyond a generalized expectation of privacy, many municipalities, whether for reasons of privacy, sanitation, or both, reinforce confidence in the integrity of sealed trash containers by “prohibiting] anyone, except authorized employees of the Town ... , to rummage into, pick up, collect, move or otherwise interfere with articles or materials placed on . . . any public street for collection.” United States v. Dzialak, 441 F. 2d 212, 215 (CA2 1971) (paraphrasing ordinance for town of Cheektowaga, New York). See also United States v. Vahalik, 606 F. 2d 99, 100 (CA5 1979) (per curiam); Magda v. Benson, 536 F. 2d 111, 112 (CA6 1976) (per curiam); People v. Rooney, 175 Cal. App. 3d 634, 645, 221 Cal. Rptr. 49, 56 (1985), cert. dism’d, 483 U. S. 307 (1987); People v. Krivda, 5 Cal. 3d 357, 366, 486 P. 2d 1262, 1268 (1971), vacated and remanded, 409 U. S. 33 (1972); State v. Brown, 20 Ohio App. 3d 36, 38, n. 3, 484 N. E. 2d 215, 218, n. 3 (1984). In fact, the California Constitution, as interpreted by the State’s highest court, guarantees a right of privacy in trash vis-a-vis government officials. See Krivda, supra (recognizing right); In re Lance W., 37 Cal. 3d 873, 886-887, 694 P. 2d 744, 752-753 (1985) (later constitutional amendment abolished exclusionary remedy but left intact the substance of the right).

*53That is not to deny that isolated intrusions into opaque, sealed trash containers occur. When, acting on their own, “animals, children, scavengers, snoops, [or] other members of the public,” ante, at 40 (footnotes omitted), actually rummage through a bag of trash and expose its contents to plain view, “police cannot reasonably be expected to avert their eyes from evidence of criminal activity that could have been observed by any member of the public,” ante, at 41. That much follows from cases like Jacobsen, 466 U. S., at 117, 120, n. 17 (emphasis added), which held that police may constitutionally inspect a package whose “integrity” a private carrier has already “compromised,” because “[t]he Fourth Amendment is implicated only if the authorities use information with respect to which the expectation of privacy has not already been frustrated”; and California v. Ciraolo, 476 U. S. 207, 213-214 (1986) (emphasis added), which held that the Fourth Amendment does not prohibit police from observing what “[a]ny member of the public flying in this airspace who glanced down could have seen.”

Had Greenwood flaunted his intimate activity by strewing his trash all over the curb for all to see, or had some nongovernmental intruder invaded his privacy and done the same, I could accept the Court’s conclusion that an expectation of privacy would have been unreasonable. Similarly, had police searching the city dump run across incriminating evidence that, despite commingling with the trash of others, still retained its identity as Greenwood’s, we would have a different case. But all that Greenwood “exposed ... to the public,” ante, at 40, were the exteriors of several opaque, sealed containers. Until the bags were opened by police, they hid their contents from the public’s view every bit as much as did Chadwick’s double-locked footlocker and Robbins’ green, plastic wrapping. Faithful application of the warrant requirement does not require police to “avert their eyes from evidence of criminal activity that could have been observed by any member of the public.” Rather, it only requires them *54to adhere to norms of privacy that members of the public plainly acknowledge.

The mere 'possibility that unwelcome meddlers might open and rummage through the containers does not negate the expectation of privacy in their contents any more than the possibility of a burglary negates an expectation of privacy in the home; or the possibility of a private intrusion negates an expectation of privacy in an unopened package; or the possibility that an operator will listen in on a telephone conversation negates an expectation of privacy in the words spoken on the telephone. “What a person. . . seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.” Katz, 389 U. S., at 351-352. We have therefore repeatedly rejected attempts to justify a State’s invasion of privacy on the ground that the privacy is not absolute. See Chapman v. United States, 365 U. S. 610, 616-617 (1961) (search of a house invaded tenant’s Fourth Amendment rights even though landlord had authority to enter house for some purposes); Stoner v. California, 376 U. S. 483, 487-490 (1964) (implicit consent to janitorial personnel to enter motel room does not amount to consent to police search of room); O’Connor v. Ortega, 480 U. S. 709, 717 (1987) (a government employee has a reasonable expectation of privacy in his office, even though “it is the nature of government offices that others — such as fellow employees, supervisors, consensual visitors, and the general public — may have frequent access to an individual’s office”). As Justice Sc alia aptly put it, the Fourth Amendment protects “privacy . . . not solitude.” O’Connor, supra, at 730 (opinion concurring in judgment).

Nor is it dispositive that “respondents placed their refuse at the curb for the express purpose of conveying it to a third party, . . . who might himself have sorted through respondents’ trash or permitted others, such as the police, to do so.” Ante, at 40. In the first place, Greenwood can hardly be faulted for leaving trash on his curb when a county ordinance *55commanded him to do so, Orange County Code §4-3-45(a) (1986) (must “remov[e] from the premises at least once each week” all “solid waste created, produced or accumulated in or about [his] dwelling house”), and prohibited him from disposing of it in any other way, see Orange County Code § 3-3-85 (1988) (burning trash is unlawful). Unlike in other circumstances where privacy is compromised, Greenwood could not “avoid exposing personal belongings ... by simply leaving them at home.” O’Connor, supra, at 725. More importantly, even the voluntary relinquishment of possession or control over an effect does not necessarily amount to a relinquishment of a privacy expectation in it. Were it otherwise, a letter or package would lose all Fourth Amendment protection when placed in a mailbox or other depository with the “express purpose” of entrusting it to the postal officer or a private carrier; those bailees are just as likely as trash collectors (and certainly have greater incentive) to “sor[t] through” the personal effects entrusted to them, “or permi[t] others, such as police to do so.” Yet, it has been clear for at least 110 years that the possibility of such an intrusion does not justify a warrantless search by police in the first instance. See Ex parte Jackson, 96 U. S. 727 (1878); United States v. Van Leeuwen, 397 U. S. 249 (1970); United States v. Jacobsen, supra. 4

Ill

In holding that the warrantless search of Greenwood’s trash was consistent with the Fourth Amendment, the'Court paints a grim picture of our society. It depicts a society in which local authorities may command their citizens to dispose of their personal effects in the manner least protective of the *56“sanctity of [the] home and the privacies of life,” Boyd v. United States, 116 U. S., at 630, and then monitor them arbitrarily and without judicial oversight — a society that is not prepared to recognize as reasonable an individual’s expectation of privacy in the most private of personal effects sealed in an opaque container and disposed of in a manner designed to commingle it imminently and inextricably with the trash of others. Ante, at 39. The American society with which I am familiar “chooses to dwell in reasonable security and freedom from surveillance,” Johnson v. United States, 333 U. S. 10, 14 (1948), and is more dedicated to individual liberty and more sensitive to intrusions on the sanctity of the home than the Court is willing to acknowledge.

I dissent.

Chief Justice ROBERTS delivered the opinion of the Court.

This case presents the question whether the Government conducts a search under the Fourth Amendment when it accesses historical cell phone records that provide a comprehensive chronicle of the user's past movements.

I

A

There are 396 million cell phone service accounts in the United States-for a Nation of 326 million people. Cell phones perform their wide and growing variety of functions by connecting to a set of radio antennas called "cell sites." Although cell sites are usually mounted on a tower, they can also be found on light posts, flagpoles, church steeples, or the sides of buildings. Cell sites typically have several directional antennas that divide the covered area into sectors.

Cell phones continuously scan their environment looking for the best signal, which generally comes from the closest cell site. Most modern devices, such as smartphones, tap into the wireless network several times a minute whenever their signal is on, even if the owner is not using one of the phone's features. Each time the phone connects to a cell site, it generates a time-stamped record known as cell-site location information (CSLI). The precision of this information depends on the size of the geographic area covered by the cell site. The greater the concentration of cell sites, the smaller the coverage area. As data usage from cell phones has increased, *2212wireless carriers have installed more cell sites to handle the traffic. That has led to increasingly compact coverage areas, especially in urban areas.

Wireless carriers collect and store CSLI for their own business purposes, including finding weak spots in their network and applying "roaming" charges when another carrier routes data through their cell sites. In addition, wireless carriers often sell aggregated location records to data brokers, without individual identifying information of the sort at issue here. While carriers have long retained CSLI for the start and end of incoming calls, in recent years phone companies have also collected location information from the transmission of text messages and routine data connections. Accordingly, modern cell phones generate increasingly vast amounts of increasingly precise CSLI.

B

In 2011, police officers arrested four men suspected of robbing a series of Radio Shack and (ironically enough) T-Mobile stores in Detroit. One of the men confessed that, over the previous four months, the group (along with a rotating cast of getaway drivers and lookouts) had robbed nine different stores in Michigan and Ohio. The suspect identified 15 accomplices who had participated in the heists and gave the FBI some of their cell phone numbers; the FBI then reviewed his call records to identify additional numbers that he had called around the time of the robberies.

Based on that information, the prosecutors applied for court orders under the Stored Communications Act to obtain cell phone records for petitioner Timothy Carpenter and several other suspects. That statute, as amended in 1994, permits the Government to compel the disclosure of certain telecommunications records when it "offers specific and articulable facts showing that there are reasonable grounds to believe" that the records sought "are relevant and material to an ongoing criminal investigation." 18 U.S.C. § 2703(d). Federal Magistrate Judges issued two orders directing Carpenter's wireless carriers-MetroPCS and Sprint-to disclose "cell/site sector [information] for [Carpenter's] telephone[ ] at call origination and at call termination for incoming and outgoing calls" during the four-month period when the string of robberies occurred. App. to Pet. for Cert. 60a, 72a. The first order sought 152 days of cell-site records from MetroPCS, which produced records spanning 127 days. The second order requested seven days of CSLI from Sprint, which produced two days of records covering the period when Carpenter's phone was "roaming" in northeastern Ohio. Altogether the Government obtained 12,898 location points cataloging Carpenter's movements-an average of 101 data points per day.

Carpenter was charged with six counts of robbery and an additional six counts of carrying a firearm during a federal crime of violence. See 18 U.S.C. §§ 924(c), 1951(a). Prior to trial, Carpenter moved to suppress the cell-site data provided by the wireless carriers. He argued that the Government's seizure of the records violated the Fourth Amendment because they had been obtained without a warrant supported by probable cause. The District Court denied the motion. App. to Pet. for Cert. 38a-39a.

At trial, seven of Carpenter's confederates pegged him as the leader of the operation. In addition, FBI agent Christopher Hess offered expert testimony about the cell-site data. Hess explained that each time a cell phone taps into the wireless network, the carrier logs a time-stamped record of the cell site and particular sector that were used. With this information, *2213Hess produced maps that placed Carpenter's phone near four of the charged robberies. In the Government's view, the location records clinched the case: They confirmed that Carpenter was "right where the ... robbery was at the exact time of the robbery." App. 131 (closing argument). Carpenter was convicted on all but one of the firearm counts and sentenced to more than 100 years in prison.

The Court of Appeals for the Sixth Circuit affirmed. 819 F.3d 880 (2016). The court held that Carpenter lacked a reasonable expectation of privacy in the location information collected by the FBI because he had shared that information with his wireless carriers. Given that cell phone users voluntarily convey cell-site data to their carriers as "a means of establishing communication," the court concluded that the resulting business records are not entitled to Fourth Amendment protection. Id., at 888 (quoting Smith v. Maryland, 442 U.S. 735, 741, 99 S.Ct. 2577, 61 L.Ed.2d 220 (1979) ).

We granted certiorari. 582 U.S. ----, 137 S.Ct. 2211, 198 L.Ed.2d 657 (2017).

II

A

The Fourth Amendment protects "[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures." The "basic purpose of this Amendment," our cases have recognized, "is to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials." Camara v. Municipal Court of City and County of San Francisco, 387 U.S. 523, 528, 87 S.Ct. 1727, 18 L.Ed.2d 930 (1967). The Founding generation crafted the Fourth Amendment as a "response to the reviled 'general warrants' and 'writs of assistance' of the colonial era, which allowed British officers to rummage through homes in an unrestrained search for evidence of criminal activity." Riley v. California, 573 U.S. ----, ----, 134 S.Ct. 2473, 2494, 189 L.Ed.2d 430 (2014). In fact, as John Adams recalled, the patriot James Otis's 1761 speech condemning writs of assistance was "the first act of opposition to the arbitrary claims of Great Britain" and helped spark the Revolution itself. Id., at ---- - ----, 134 S.Ct., at 2494 (quoting 10 Works of John Adams 248 (C. Adams ed. 1856)).

For much of our history, Fourth Amendment search doctrine was "tied to common-law trespass" and focused on whether the Government "obtains information by physically intruding on a constitutionally protected area." United States v. Jones, 565 U.S. 400, 405, 406, n. 3, 132 S.Ct. 945, 181 L.Ed.2d 911 (2012). More recently, the Court has recognized that "property rights are not the sole measure of Fourth Amendment violations." Soldal v. Cook County, 506 U.S. 56, 64, 113 S.Ct. 538, 121 L.Ed.2d 450 (1992). In Katz v. United States, 389 U.S. 347, 351, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967), we established that "the Fourth Amendment protects people, not places," and expanded our conception of the Amendment to protect certain expectations of privacy as well. When an individual "seeks to preserve something as private," and his expectation of privacy is "one that society is prepared to recognize as reasonable," we have held that official intrusion into that private sphere generally qualifies as a search and requires a warrant supported by probable cause. Smith, 442 U.S., at 740, 99 S.Ct. 2577 (internal quotation marks and alterations omitted).

Although no single rubric definitively resolves which expectations of privacy *2214are entitled to protection,1 the analysis is informed by historical understandings "of what was deemed an unreasonable search and seizure when [the Fourth Amendment] was adopted." Carroll v. United States, 267 U.S. 132, 149, 45 S.Ct. 280, 69 L.Ed. 543 (1925). On this score, our cases have recognized some basic guideposts. First, that the Amendment seeks to secure "the privacies of life" against "arbitrary power." Boyd v. United States, 116 U.S. 616, 630, 6 S.Ct. 524, 29 L.Ed. 746 (1886). Second, and relatedly, that a central aim of the Framers was "to place obstacles in the way of a too permeating police surveillance." United States v. Di Re, 332 U.S. 581, 595, 68 S.Ct. 222, 92 L.Ed. 210 (1948).

We have kept this attention to Founding-era understandings in mind when applying the Fourth Amendment to innovations in surveillance tools. As technology has enhanced the Government's capacity to encroach upon areas normally guarded from inquisitive eyes, this Court has sought to "assure [ ] preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted." Kyllo v. United States, 533 U.S. 27, 34, 121 S.Ct. 2038, 150 L.Ed.2d 94 (2001). For that reason, we rejected in Kyllo a "mechanical interpretation" of the Fourth Amendment and held that use of a thermal imager to detect heat radiating from the side of the defendant's home was a search. Id., at 35, 121 S.Ct. 2038. Because any other conclusion would leave homeowners "at the mercy of advancing technology," we determined that the Government-absent a warrant-could not capitalize on such new sense-enhancing technology to explore what was happening within the home. Ibid.

Likewise in Riley, the Court recognized the "immense storage capacity" of modern cell phones in holding that police officers must generally obtain a warrant before searching the contents of a phone. 573 U.S., at ----, 134 S.Ct., at 2489. We explained that while the general rule allowing warrantless searches incident to arrest "strikes the appropriate balance in the context of physical objects, neither of its rationales has much force with respect to" the vast store of sensitive information on a cell phone. Id., at ----, 134 S.Ct., at 2484.

B

The case before us involves the Government's acquisition of wireless carrier cell-site records revealing the location of Carpenter's cell phone whenever it made or received calls. This sort of digital data-personal location information maintained by a third party-does not fit neatly under existing precedents. Instead, requests for cell-site records lie at the intersection of two lines of cases, both of which inform *2215our understanding of the privacy interests at stake.

The first set of cases addresses a person's expectation of privacy in his physical location and movements. In United States v. Knotts, 460 U.S. 276, 103 S.Ct. 1081, 75 L.Ed.2d 55 (1983), we considered the Government's use of a "beeper" to aid in tracking a vehicle through traffic. Police officers in that case planted a beeper in a container of chloroform before it was purchased by one of Knotts's co-conspirators. The officers (with intermittent aerial assistance) then followed the automobile carrying the container from Minneapolis to Knotts's cabin in Wisconsin, relying on the beeper's signal to help keep the vehicle in view. The Court concluded that the "augment[ed]" visual surveillance did not constitute a search because "[a] person traveling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another." Id., at 281, 282, 103 S.Ct. 1081. Since the movements of the vehicle and its final destination had been "voluntarily conveyed to anyone who wanted to look," Knotts could not assert a privacy interest in the information obtained. Id., at 281, 103 S.Ct. 1081.

This Court in Knotts, however, was careful to distinguish between the rudimentary tracking facilitated by the beeper and more sweeping modes of surveillance. The Court emphasized the "limited use which the government made of the signals from this particular beeper" during a discrete "automotive journey." Id., at 284, 285, 103 S.Ct. 1081. Significantly, the Court reserved the question whether "different constitutional principles may be applicable" if "twenty-four hour surveillance of any citizen of this country [were] possible." Id., at 283-284, 103 S.Ct. 1081.

Three decades later, the Court considered more sophisticated surveillance of the sort envisioned in Knotts and found that different principles did indeed apply. In United States v. Jones, FBI agents installed a GPS tracking device on Jones's vehicle and remotely monitored the vehicle's movements for 28 days. The Court decided the case based on the Government's physical trespass of the vehicle. 565 U.S., at 404-405, 132 S.Ct. 945. At the same time, five Justices agreed that related privacy concerns would be raised by, for example, "surreptitiously activating a stolen vehicle detection system" in Jones's car to track Jones himself, or conducting GPS tracking of his cell phone. Id., at 426, 428, 132 S.Ct. 945 (ALITO, J., concurring in judgment); id., at 415, 132 S.Ct. 945 (SOTOMAYOR, J., concurring). Since GPS monitoring of a vehicle tracks "every movement" a person makes in that vehicle, the concurring Justices concluded that "longer term GPS monitoring in investigations of most offenses impinges on expectations of privacy"-regardless whether those movements were disclosed to the public at large. Id., at 430, 132 S.Ct. 945 (opinion of Alito, J.); id., at 415, 132 S.Ct. 945 (opinion of Sotomayor, J.).2

*2216In a second set of decisions, the Court has drawn a line between what a person keeps to himself and what he shares with others. We have previously held that "a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties." Smith, 442 U.S., at 743-744, 99 S.Ct. 2577. That remains true "even if the information is revealed on the assumption that it will be used only for a limited purpose." United States v. Miller, 425 U.S. 435, 443, 96 S.Ct. 1619, 48 L.Ed.2d 71 (1976). As a result, the Government is typically free to obtain such information from the recipient without triggering Fourth Amendment protections.

This third-party doctrine largely traces its roots to Miller . While investigating Miller for tax evasion, the Government subpoenaed his banks, seeking several months of canceled checks, deposit slips, and monthly statements. The Court rejected a Fourth Amendment challenge to the records collection. For one, Miller could "assert neither ownership nor possession" of the documents; they were "business records of the banks." Id., at 440, 96 S.Ct. 1619. For another, the nature of those records confirmed Miller's limited expectation of privacy, because the checks were "not confidential communications but negotiable instruments to be used in commercial transactions," and the bank statements contained information "exposed to [bank] employees in the ordinary course of business." Id., at 442, 96 S.Ct. 1619. The Court thus concluded that Miller had "take[n] the risk, in revealing his affairs to another, that the information [would] be conveyed by that person to the Government." Id., at 443, 96 S.Ct. 1619.

Three years later, Smith applied the same principles in the context of information conveyed to a telephone company. The Court ruled that the Government's use of a pen register-a device that recorded the outgoing phone numbers dialed on a landline telephone-was not a search. Noting the pen register's "limited capabilities," the Court "doubt[ed] that people in general entertain any actual expectation of privacy in the numbers they dial." 442 U.S., at 742, 99 S.Ct. 2577. Telephone subscribers know, after all, that the numbers are used by the telephone company "for a variety of legitimate business purposes," including routing calls. Id., at 743, 99 S.Ct. 2577. And at any rate, the Court explained, such an expectation "is not one that society is prepared to recognize as reasonable." Ibid. (internal quotation marks omitted). When Smith placed a call, he "voluntarily conveyed" the dialed numbers to the phone company by "expos[ing] that information to its equipment in the ordinary course of business." Id., at 744, 99 S.Ct. 2577 (internal quotation marks omitted). Once again, we held that the defendant "assumed the risk" that the company's records "would be divulged to police." Id., at 745, 99 S.Ct. 2577.

III

The question we confront today is how to apply the Fourth Amendment to a new phenomenon: the ability to chronicle a person's past movements through the record of his cell phone signals. Such tracking partakes of many of the qualities of the GPS monitoring we considered in Jones . Much like GPS tracking of a vehicle, cell phone location information is detailed, encyclopedic, and effortlessly compiled.

At the same time, the fact that the individual continuously reveals his location to his wireless carrier implicates the third-party principle of Smith and Miller . But while the third-party doctrine applies to telephone numbers and bank records, it is not clear whether its logic extends to the qualitatively different category of cell-site *2217records. After all, when Smith was decided in 1979, few could have imagined a society in which a phone goes wherever its owner goes, conveying to the wireless carrier not just dialed digits, but a detailed and comprehensive record of the person's movements.

We decline to extend Smith and Miller to cover these novel circumstances. Given the unique nature of cell phone location records, the fact that the information is held by a third party does not by itself overcome the user's claim to Fourth Amendment protection. Whether the Government employs its own surveillance technology as in Jones or leverages the technology of a wireless carrier, we hold that an individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through CSLI. The location information obtained from Carpenter's wireless carriers was the product of a search.3

A

A person does not surrender all Fourth Amendment protection by venturing into the public sphere. To the contrary, "what [one] seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected." Katz, 389 U.S., at 351-352, 88 S.Ct. 507. A majority of this Court has already recognized that individuals have a reasonable expectation of privacy in the whole of their physical movements. Jones, 565 U.S., at 430, 132 S.Ct. 945 (ALITO, J., concurring in judgment); id., at 415, 132 S.Ct. 945 (SOTOMAYOR, J., concurring). Prior to the digital age, law enforcement might have pursued a suspect for a brief stretch, but doing so "for any extended period of time was difficult and costly and therefore rarely undertaken." Id., at 429, 132 S.Ct. 945 (opinion of Alito, J.). For that reason, "society's expectation has been that law enforcement agents and others would not-and indeed, in the main, simply could not-secretly monitor and catalogue every single movement of an individual's car for a very long period." Id., at 430, 132 S.Ct. 945.

Allowing government access to cell-site records contravenes that expectation. Although such records are generated for commercial purposes, that distinction does not negate Carpenter's anticipation of privacy in his physical location. Mapping a cell phone's location over the course of 127 days provides an all-encompassing record of the holder's whereabouts. As with GPS information, the time-stamped data provides an intimate window into a person's life, revealing not only his particular movements, but through them his "familial, political, professional, religious, and sexual associations." Id., at 415, 132 S.Ct. 945 (opinion of SOTOMAYOR, J.). These location records "hold for many Americans the 'privacies of life.' " Riley, 573 U.S., at ----, 134 S.Ct., at 2494-2495 (quoting Boyd, 116 U.S., at 630, 6 S.Ct. 524 ). And like GPS monitoring, cell phone *2218tracking is remarkably easy, cheap, and efficient compared to traditional investigative tools. With just the click of a button, the Government can access each carrier's deep repository of historical location information at practically no expense.

In fact, historical cell-site records present even greater privacy concerns than the GPS monitoring of a vehicle we considered in Jones . Unlike the bugged container in Knotts or the car in Jones, a cell phone-almost a "feature of human anatomy," Riley, 573 U.S., at ----, 134 S.Ct., at 2484 -tracks nearly exactly the movements of its owner. While individuals regularly leave their vehicles, they compulsively carry cell phones with them all the time. A cell phone faithfully follows its owner beyond public thoroughfares and into private residences, doctor's offices, political headquarters, and other potentially revealing locales. See id., at ----, 134 S.Ct., at 2490 (noting that "nearly three-quarters of smart phone users report being within five feet of their phones most of the time, with 12% admitting that they even use their phones in the shower"); contrast Cardwell v. Lewis, 417 U.S. 583, 590, 94 S.Ct. 2464, 41 L.Ed.2d 325 (1974) (plurality opinion) ("A car has little capacity for escaping public scrutiny."). Accordingly, when the Government tracks the location of a cell phone it achieves near perfect surveillance, as if it had attached an ankle monitor to the phone's user.

Moreover, the retrospective quality of the data here gives police access to a category of information otherwise unknowable. In the past, attempts to reconstruct a person's movements were limited by a dearth of records and the frailties of recollection. With access to CSLI, the Government can now travel back in time to retrace a person's whereabouts, subject only to the retention polices of the wireless carriers, which currently maintain records for up to five years. Critically, because location information is continually logged for all of the 400 million devices in the United States-not just those belonging to persons who might happen to come under investigation-this newfound tracking capacity runs against everyone. Unlike with the GPS device in Jones, police need not even know in advance whether they want to follow a particular individual, or when.

Whoever the suspect turns out to be, he has effectively been tailed every moment of every day for five years, and the police may-in the Government's view-call upon the results of that surveillance without regard to the constraints of the Fourth Amendment. Only the few without cell phones could escape this tireless and absolute surveillance.

The Government and Justice KENNEDY contend, however, that the collection of CSLI should be permitted because the data is less precise than GPS information. Not to worry, they maintain, because the location records did "not on their own suffice to place [Carpenter] at the crime scene"; they placed him within a wedge-shaped sector ranging from one-eighth to four square miles. Brief for United States 24; see post, at 2232 - 2233. Yet the Court has already rejected the proposition that "inference insulates a search." Kyllo, 533 U.S., at 36, 121 S.Ct. 2038. From the 127 days of location data it received, the Government could, in combination with other information, deduce a detailed log of Carpenter's movements, including when he was at the site of the robberies. And the Government thought the CSLI accurate enough to highlight it during the closing argument of his trial. App. 131.

At any rate, the rule the Court adopts "must take account of more sophisticated systems that are already in use or in development."

*2219Kyllo, 533 U.S., at 36, 121 S.Ct. 2038. While the records in this case reflect the state of technology at the start of the decade, the accuracy of CSLI is rapidly approaching GPS-level precision. As the number of cell sites has proliferated, the geographic area covered by each cell sector has shrunk, particularly in urban areas. In addition, with new technology measuring the time and angle of signals hitting their towers, wireless carriers already have the capability to pinpoint a phone's location within 50 meters. Brief for Electronic Frontier Foundation et al. as Amici Curiae 12 (describing triangulation methods that estimate a device's location inside a given cell sector).

Accordingly, when the Government accessed CSLI from the wireless carriers, it invaded Carpenter's reasonable expectation of privacy in the whole of his physical movements.

B

The Government's primary contention to the contrary is that the third-party doctrine governs this case. In its view, cell-site records are fair game because they are "business records" created and maintained by the wireless carriers. The Government (along with Justice KENNEDY) recognizes that this case features new technology, but asserts that the legal question nonetheless turns on a garden-variety request for information from a third-party witness. Brief for United States 32-34; post, at 2229 - 2231.

The Government's position fails to contend with the seismic shifts in digital technology that made possible the tracking of not only Carpenter's location but also everyone else's, not for a short period but for years and years. Sprint Corporation and its competitors are not your typical witnesses. Unlike the nosy neighbor who keeps an eye on comings and goings, they are ever alert, and their memory is nearly infallible. There is a world of difference between the limited types of personal information addressed in Smith and Miller and the exhaustive chronicle of location information casually collected by wireless carriers today. The Government thus is not asking for a straightforward application of the third-party doctrine, but instead a significant extension of it to a distinct category of information.

The third-party doctrine partly stems from the notion that an individual has a reduced expectation of privacy in information knowingly shared with another. But the fact of "diminished privacy interests does not mean that the Fourth Amendment falls out of the picture entirely." Riley, 573 U.S., at ----, 134 S.Ct., at 2488. Smith and Miller, after all, did not rely solely on the act of sharing. Instead, they considered "the nature of the particular documents sought" to determine whether "there is a legitimate 'expectation of privacy' concerning their contents." Miller, 425 U.S., at 442, 96 S.Ct. 1619. Smith pointed out the limited capabilities of a pen register; as explained in Riley, telephone call logs reveal little in the way of "identifying information." Smith, 442 U.S., at 742, 99 S.Ct. 2577 ; Riley, 573 U.S., at ----, 134 S.Ct., at 2493. Miller likewise noted that checks were "not confidential communications but negotiable instruments to be used in commercial transactions." 425 U.S., at 442, 96 S.Ct. 1619. In mechanically applying the third-party doctrine to this case, the Government fails to appreciate that there are no comparable limitations on the revealing nature of CSLI.

The Court has in fact already shown special solicitude for location information in the third-party context. In Knotts, the Court relied on Smith to hold that an individual has no reasonable expectation of privacy in public movements that he "voluntarily *2220conveyed to anyone who wanted to look." Knotts, 460 U.S., at 281, 103 S.Ct. 1081 ; see id., at 283, 103 S.Ct. 1081 (discussing Smith ). But when confronted with more pervasive tracking, five Justices agreed that longer term GPS monitoring of even a vehicle traveling on public streets constitutes a search. Jones, 565 U.S., at 430, 132 S.Ct. 945 (ALITO, J., concurring in judgment); id., at 415, 132 S.Ct. 945 (SOTOMAYOR, J., concurring). Justice GORSUCH wonders why "someone's location when using a phone" is sensitive, post, at 2262, and Justice KENNEDY assumes that a person's discrete movements "are not particularly private," post, at 2232. Yet this case is not about "using a phone" or a person's movement at a particular time. It is about a detailed chronicle of a person's physical presence compiled every day, every moment, over several years. Such a chronicle implicates privacy concerns far beyond those considered in Smith and Miller .

Neither does the second rationale underlying the third-party doctrine-voluntary exposure-hold up when it comes to CSLI. Cell phone location information is not truly "shared" as one normally understands the term. In the first place, cell phones and the services they provide are "such a pervasive and insistent part of daily life" that carrying one is indispensable to participation in modern society. Riley, 573 U.S., at ----, 134 S.Ct., at 2484. Second, a cell phone logs a cell-site record by dint of its operation, without any affirmative act on the part of the user beyond powering up. Virtually any activity on the phone generates CSLI, including incoming calls, texts, or e-mails and countless other data connections that a phone automatically makes when checking for news, weather, or social media updates. Apart from disconnecting the phone from the network, there is no way to avoid leaving behind a trail of location data. As a result, in no meaningful sense does the user voluntarily "assume[ ] the risk" of turning over a comprehensive dossier of his physical movements. Smith, 442 U.S., at 745, 99 S.Ct. 2577.

We therefore decline to extend Smith and Miller to the collection of CSLI. Given the unique nature of cell phone location information, the fact that the Government obtained the information from a third party does not overcome Carpenter's claim to Fourth Amendment protection. The Government's acquisition of the cell-site records was a search within the meaning of the Fourth Amendment.

* * *

Our decision today is a narrow one. We do not express a view on matters not before us: real-time CSLI or "tower dumps" (a download of information on all the devices that connected to a particular cell site during a particular interval). We do not disturb the application of Smith and Miller or call into question conventional surveillance techniques and tools, such as security cameras. Nor do we address other business records that might incidentally reveal location information. Further, our opinion does not consider other collection techniques involving foreign affairs or national security. As Justice Frankfurter noted when considering new innovations in airplanes and radios, the Court must tread carefully in such cases, to ensure that we do not "embarrass the future." Northwest Airlines, Inc. v. Minnesota, 322 U.S. 292, 300, 64 S.Ct. 950, 88 L.Ed. 1283 (1944).4

*2221IV

Having found that the acquisition of Carpenter's CSLI was a search, we also conclude that the Government must generally obtain a warrant supported by probable cause before acquiring such records. Although the "ultimate measure of the constitutionality of a governmental search is 'reasonableness,' " our cases establish that warrantless searches are typically unreasonable where "a search is undertaken by law enforcement officials to discover evidence of criminal wrongdoing." Vernonia School Dist. 47J v. Acton, 515 U.S. 646, 652-653, 115 S.Ct. 2386, 132 L.Ed.2d 564 (1995). Thus, "[i]n the absence of a warrant, a search is reasonable only if it falls within a specific exception to the warrant requirement." Riley, 573 U.S., at ----, 134 S.Ct., at 2482.

The Government acquired the cell-site records pursuant to a court order issued under the Stored Communications Act, which required the Government to show "reasonable grounds" for believing that the records were "relevant and material to an ongoing investigation." 18 U.S.C. § 2703(d). That showing falls well short of the probable cause required for a warrant. The Court usually requires "some quantum of individualized suspicion" before a search or seizure may take place. United States v. Martinez-Fuerte, 428 U.S. 543, 560-561, 96 S.Ct. 3074, 49 L.Ed.2d 1116 (1976). Under the standard in the Stored Communications Act, however, law enforcement need only show that the cell-site evidence might be pertinent to an ongoing investigation-a "gigantic" departure from the probable cause rule, as the Government explained below. App. 34. Consequently, an order issued under Section 2703(d) of the Act is not a permissible mechanism for accessing historical cell-site records. Before compelling a wireless carrier to turn over a subscriber's CSLI, the Government's obligation is a familiar one-get a warrant.

Justice ALITO contends that the warrant requirement simply does not apply when the Government acquires records using compulsory process. Unlike an actual search, he says, subpoenas for documents do not involve the direct taking of evidence; they are at most a "constructive search" conducted by the target of the subpoena. Post, at 2252 - 2253. Given this lesser intrusion on personal privacy, Justice ALITO argues that the compulsory production of records is not held to the same probable cause standard. In his view, this Court's precedents set forth a categorical rule-separate and distinct from the third-party doctrine-subjecting subpoenas to lenient scrutiny without regard to the suspect's expectation of privacy in the records. Post, at 2250 - 2257.

But this Court has never held that the Government may subpoena third parties for records in which the suspect has a reasonable expectation of privacy. Almost all of the examples Justice ALITO cites, see post, at 2253 - 2255, contemplated requests for evidence implicating diminished privacy interests or for a corporation's own books.5 The lone exception, of course, is *2222Miller, where the Court's analysis of the third-party subpoena merged with the application of the third-party doctrine. 425 U.S., at 444, 96 S.Ct. 1619 (concluding that Miller lacked the necessary privacy interest to contest the issuance of a subpoena to his bank).

Justice ALITO overlooks the critical issue. At some point, the dissent should recognize that CSLI is an entirely different species of business record-something that implicates basic Fourth Amendment concerns about arbitrary government power much more directly than corporate tax or payroll ledgers. When confronting new concerns wrought by digital technology, this Court has been careful not to uncritically extend existing precedents. See Riley, 573 U.S., at ----, 134 S.Ct., at 2485 ("A search of the information on a cell phone bears little resemblance to the type of brief physical search considered [in prior precedents].").

If the choice to proceed by subpoena provided a categorical limitation on Fourth Amendment protection, no type of record would ever be protected by the warrant requirement. Under Justice ALITO's view, private letters, digital contents of a cell phone-any personal information reduced to document form, in fact-may be collected by subpoena for no reason other than "official curiosity." United States v. Morton Salt Co., 338 U.S. 632, 652, 70 S.Ct. 357, 94 L.Ed. 401 (1950). Justice KENNEDY declines to adopt the radical implications of this theory, leaving open the question whether the warrant requirement applies "when the Government obtains the modern-day equivalents of an individual's own 'papers' or 'effects,' even when those papers or effects are held by a third party." Post, at 2230 (citing United States v. Warshak, 631 F.3d 266, 283-288 (C.A.6 2010) ). That would be a sensible exception, because it would prevent the subpoena doctrine from overcoming any reasonable expectation of privacy. If the third-party doctrine does not apply to the "modern-day equivalents of an individual's own 'papers' or 'effects,' " then the clear implication is that the documents should receive full Fourth Amendment protection. We simply think that such protection should extend as well to a detailed log of a person's movements over several years.

This is certainly not to say that all orders compelling the production of documents will require a showing of probable cause. The Government will be able to use subpoenas to acquire records in the overwhelming majority of investigations. We hold only that a warrant is required in the rare case where the suspect has a legitimate privacy interest in records held by a third party.

Further, even though the Government will generally need a warrant to access CSLI, case-specific exceptions may support a warrantless search of an individual's cell-site records under certain circumstances. "One well-recognized exception applies when ' "the exigencies of the situation" make the needs of law enforcement so compelling that [a] warrantless search is objectively reasonable under the Fourth Amendment.' " Kentucky v. King, 563 U.S. 452, 460, 131 S.Ct. 1849, 179 L.Ed.2d 865 (2011) (quoting *2223Mincey v. Arizona, 437 U.S. 385, 394, 98 S.Ct. 2408, 57 L.Ed.2d 290 (1978) ). Such exigencies include the need to pursue a fleeing suspect, protect individuals who are threatened with imminent harm, or prevent the imminent destruction of evidence. 563 U.S., at 460, and n. 3, 131 S.Ct. 1849.

As a result, if law enforcement is confronted with an urgent situation, such fact-specific threats will likely justify the warrantless collection of CSLI. Lower courts, for instance, have approved warrantless searches related to bomb threats, active shootings, and child abductions. Our decision today does not call into doubt warrantless access to CSLI in such circumstances. While police must get a warrant when collecting CSLI to assist in the mine-run criminal investigation, the rule we set forth does not limit their ability to respond to an ongoing emergency.

* * *

As Justice Brandeis explained in his famous dissent, the Court is obligated-as "[s]ubtler and more far-reaching means of invading privacy have become available to the Government"-to ensure that the "progress of science" does not erode Fourth Amendment protections. Olmstead v. United States, 277 U.S. 438, 473-474, 48 S.Ct. 564, 72 L.Ed. 944 (1928). Here the progress of science has afforded law enforcement a powerful new tool to carry out its important responsibilities. At the same time, this tool risks Government encroachment of the sort the Framers, "after consulting the lessons of history," drafted the Fourth Amendment to prevent. Di Re, 332 U.S., at 595, 68 S.Ct. 222.

We decline to grant the state unrestricted access to a wireless carrier's database of physical location information. In light of the deeply revealing nature of CSLI, its depth, breadth, and comprehensive reach, and the inescapable and automatic nature of its collection, the fact that such information is gathered by a third party does not make it any less deserving of Fourth Amendment protection. The Government's acquisition of the cell-site records here was a search under that Amendment.

The judgment of the Court of Appeals is reversed, and the case is remanded for further proceedings consistent with this opinion.

It is so ordered.

Justice KENNEDY, with whom Justice THOMAS and Justice ALITO join, dissenting.

This case involves new technology, but the Court's stark departure from relevant Fourth Amendment precedents and principles is, in my submission, unnecessary and incorrect, requiring this respectful dissent.

The new rule the Court seems to formulate puts needed, reasonable, accepted, lawful, and congressionally authorized criminal investigations at serious risk in serious cases, often when law enforcement seeks to prevent the threat of violent crimes. And it places undue restrictions on the lawful and necessary enforcement powers exercised not only by the Federal Government, but also by law enforcement in every State and locality throughout the Nation. Adherence to this Court's longstanding precedents and analytic framework would have been the proper and prudent way to resolve this case.

The Court has twice held that individuals have no Fourth Amendment interests in business records which are possessed, owned, and controlled by a third party. United States v. Miller, 425 U.S. 435, 96 S.Ct. 1619, 48 L.Ed.2d 71 (1976) ; Smith v. Maryland, 442 U.S. 735, 99 S.Ct. 2577, 61 L.Ed.2d 220 (1979). This is true even when the records contain personal and sensitive information. So when the Government uses a subpoena to obtain, for *2224example, bank records, telephone records, and credit card statements from the businesses that create and keep these records, the Government does not engage in a search of the business's customers within the meaning of the Fourth Amendment.

In this case petitioner challenges the Government's right to use compulsory process to obtain a now-common kind of business record: cell-site records held by cell phone service providers. The Government acquired the records through an investigative process enacted by Congress. Upon approval by a neutral magistrate, and based on the Government's duty to show reasonable necessity, it authorizes the disclosure of records and information that are under the control and ownership of the cell phone service provider, not its customer. Petitioner acknowledges that the Government may obtain a wide variety of business records using compulsory process, and he does not ask the Court to revisit its precedents. Yet he argues that, under those same precedents, the Government searched his records when it used court-approved compulsory process to obtain the cell-site information at issue here.

Cell-site records, however, are no different from the many other kinds of business records the Government has a lawful right to obtain by compulsory process. Customers like petitioner do not own, possess, control, or use the records, and for that reason have no reasonable expectation that they cannot be disclosed pursuant to lawful compulsory process.

The Court today disagrees. It holds for the first time that by using compulsory process to obtain records of a business entity, the Government has not just engaged in an impermissible action, but has conducted a search of the business's customer. The Court further concludes that the search in this case was unreasonable and the Government needed to get a warrant to obtain more than six days of cell-site records.

In concluding that the Government engaged in a search, the Court unhinges Fourth Amendment doctrine from the property-based concepts that have long grounded the analytic framework that pertains in these cases. In doing so it draws an unprincipled and unworkable line between cell-site records on the one hand and financial and telephonic records on the other. According to today's majority opinion, the Government can acquire a record of every credit card purchase and phone call a person makes over months or years without upsetting a legitimate expectation of privacy. But, in the Court's view, the Government crosses a constitutional line when it obtains a court's approval to issue a subpoena for more than six days of cell-site records in order to determine whether a person was within several hundred city blocks of a crime scene. That distinction is illogical and will frustrate principled application of the Fourth Amendment in many routine yet vital law enforcement operations.

It is true that the Cyber Age has vast potential both to expand and restrict individual freedoms in dimensions not contemplated in earlier times. See Packingham v. North Carolina, 582 U.S. ----, ---- - ----, 137 S.Ct. 1730, 1735-1736, 198 L.Ed.2d 273 (2017). For the reasons that follow, however, there is simply no basis here for concluding that the Government interfered with information that the cell phone customer, either from a legal or commonsense standpoint, should have thought the law would deem owned or controlled by him.

I

Before evaluating the question presented it is helpful to understand the nature of cell-site records, how they are commonly *2225used by cell phone service providers, and their proper use by law enforcement.

When a cell phone user makes a call, sends a text message or e-mail, or gains access to the Internet, the cell phone establishes a radio connection to an antenna at a nearby cell site. The typical cell site covers a more-or-less circular geographic area around the site. It has three (or sometimes six) separate antennas pointing in different directions. Each provides cell service for a different 120-degree (or 60-degree) sector of the cell site's circular coverage area. So a cell phone activated on the north side of a cell site will connect to a different antenna than a cell phone on the south side.

Cell phone service providers create records each time a cell phone connects to an antenna at a cell site. For a phone call, for example, the provider records the date, time, and duration of the call; the phone numbers making and receiving the call; and, most relevant here, the cell site used to make the call, as well as the specific antenna that made the connection. The cell-site and antenna data points, together with the date and time of connection, are known as cell-site location information, or cell-site records. By linking an individual's cell phone to a particular 120- or 60-degree sector of a cell site's coverage area at a particular time, cell-site records reveal the general location of the cell phone user.

The location information revealed by cell-site records is imprecise, because an individual cell-site sector usually covers a large geographic area. The FBI agent who offered expert testimony about the cell-site records at issue here testified that a cell site in a city reaches between a half mile and two miles in all directions. That means a 60-degree sector covers between approximately one-eighth and two square miles (and a 120-degree sector twice that area). To put that in perspective, in urban areas cell-site records often would reveal the location of a cell phone user within an area covering between around a dozen and several hundred city blocks. In rural areas cell-site records can be up to 40 times more imprecise. By contrast, a Global Positioning System (GPS) can reveal an individual's location within around 15 feet.

Major cell phone service providers keep cell-site records for long periods of time. There is no law requiring them to do so. Instead, providers contract with their customers to collect and keep these records because they are valuable to the providers. Among other things, providers aggregate the records and sell them to third parties along with other information gleaned from cell phone usage. This data can be used, for example, to help a department store determine which of various prospective store locations is likely to get more foot traffic from middle-aged women who live in affluent zip codes. The market for cell phone data is now estimated to be in the billions of dollars. See Brief for Technology Experts as Amici Curiae 23.

Cell-site records also can serve an important investigative function, as the facts of this case demonstrate. Petitioner, Timothy Carpenter, along with a rotating group of accomplices, robbed at least six RadioShack and T-Mobile stores at gunpoint over a 2-year period. Five of those robberies occurred in the Detroit area, each crime at least four miles from the last. The sixth took place in Warren, Ohio, over 200 miles from Detroit.

The Government, of course, did not know all of these details in 2011 when it began investigating Carpenter. In April of that year police arrested four of Carpenter's co-conspirators. One of them confessed to committing nine robberies in Michigan and Ohio between December 2010 and March 2011. He identified 15 accomplices who had participated in at *2226least one of those robberies; named Carpenter as one of the accomplices; and provided Carpenter's cell phone number to the authorities. The suspect also warned that the other members of the conspiracy planned to commit more armed robberies in the immediate future.

The Government at this point faced a daunting task. Even if it could identify and apprehend the suspects, still it had to link each suspect in this changing criminal gang to specific robberies in order to bring charges and convict. And, of course, it was urgent that the Government take all necessary steps to stop the ongoing and dangerous crime spree.

Cell-site records were uniquely suited to this task. The geographic dispersion of the robberies meant that, if Carpenter's cell phone were within even a dozen to several hundred city blocks of one or more of the stores when the different robberies occurred, there would be powerful circumstantial evidence of his participation; and this would be especially so if his cell phone usually was not located in the sectors near the stores except during the robbery times.

To obtain these records, the Government applied to federal magistrate judges for disclosure orders pursuant to § 2703(d) of the Stored Communications Act. That Act authorizes a magistrate judge to issue an order requiring disclosure of cell-site records if the Government demonstrates "specific and articulable facts showing that there are reasonable grounds to believe" the records "are relevant and material to an ongoing criminal investigation." 18 U.S.C. §§ 2703(d), 2711(3). The full statutory provision is set out in the Appendix, infra .

From Carpenter's primary service provider, MetroPCS, the Government obtained records from between December 2010 and April 2011, based on its understanding that nine robberies had occurred in that timeframe. The Government also requested seven days of cell-site records from Sprint, spanning the time around the robbery in Warren, Ohio. It obtained two days of records.

These records confirmed that Carpenter's cell phone was in the general vicinity of four of the nine robberies, including the one in Ohio, at the times those robberies occurred.

II

The first Clause of the Fourth Amendment provides that "the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated." The customary beginning point in any Fourth Amendment search case is whether the Government's actions constitute a "search" of the defendant's person, house, papers, or effects, within the meaning of the constitutional provision. If so, the next question is whether that search was reasonable.

Here the only question necessary to decide is whether the Government searched anything of Carpenter's when it used compulsory process to obtain cell-site records from Carpenter's cell phone service providers. This Court's decisions in Miller and Smith dictate that the answer is no, as every Court of Appeals to have considered the question has recognized. See United States v. Thompson, 866 F.3d 1149 (C.A.10 2017) ; United States v. Graham, 824 F.3d 421 (C.A.4 2016) (en banc); United States v. Carpenter, 819 F.3d 880 (C.A.6 2016) ; United States v. Davis, 785 F.3d 498 (C.A.11 2015) (en banc); In re Application of U.S. for Historical Cell Site Data, 724 F.3d 600 (C.A.5 2013).

A

Miller and Smith hold that individuals lack any protected Fourth Amendment interests *2227in records that are possessed, owned, and controlled only by a third party. In Miller federal law enforcement officers obtained four months of the defendant's banking records. 425 U.S., at 437-438, 96 S.Ct. 1619. And in Smith state police obtained records of the phone numbers dialed from the defendant's home phone. 442 U.S., at 737, 99 S.Ct. 2577. The Court held in both cases that the officers did not search anything belonging to the defendants within the meaning of the Fourth Amendment. The defendants could "assert neither ownership nor possession" of the records because the records were created, owned, and controlled by the companies. Miller, supra, at 440, 96 S.Ct. 1619 ; see Smith, supra, at 741, 99 S.Ct. 2577. And the defendants had no reasonable expectation of privacy in information they "voluntarily conveyed to the [companies] and exposed to their employees in the ordinary course of business." Miller, supra, at 442, 96 S.Ct. 1619 ; see Smith, 442 U.S., at 744, 99 S.Ct. 2577. Rather, the defendants "assumed the risk that the information would be divulged to police." Id., at 745, 99 S.Ct. 2577.

Miller and Smith have been criticized as being based on too narrow a view of reasonable expectations of privacy. See, e.g., Ashdown, The Fourth Amendment and the "Legitimate Expectation of Privacy," 34 Vand. L. Rev. 1289, 1313-1316 (1981). Those criticisms, however, are unwarranted. The principle established in Miller and Smith is correct for two reasons, the first relating to a defendant's attenuated interest in property owned by another, and the second relating to the safeguards inherent in the use of compulsory process.

First, Miller and Smith placed necessary limits on the ability of individuals to assert Fourth Amendment interests in property to which they lack a "requisite connection." Minnesota v. Carter, 525 U.S. 83, 99, 119 S.Ct. 469, 142 L.Ed.2d 373 (1998) (KENNEDY, J., concurring). Fourth Amendment rights, after all, are personal. The Amendment protects "[t]he right of the people to be secure in their ... persons, houses, papers, and effects"-not the persons, houses, papers, and effects of others. (Emphasis added.)

The concept of reasonable expectations of privacy, first announced in Katz v. United States, 389 U.S. 347, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967), sought to look beyond the "arcane distinctions developed in property and tort law" in evaluating whether a person has a sufficient connection to the thing or place searched to assert Fourth Amendment interests in it. Rakas v. Illinois, 439 U.S. 128, 143, 99 S.Ct. 421, 58 L.Ed.2d 387 (1978). Yet "property concepts" are, nonetheless, fundamental "in determining the presence or absence of the privacy interests protected by that Amendment." Id., at 143-144, n. 12, 99 S.Ct. 421. This is so for at least two reasons. First, as a matter of settled expectations from the law of property, individuals often have greater expectations of privacy in things and places that belong to them, not to others. And second, the Fourth Amendment's protections must remain tethered to the text of that Amendment, which, again, protects only a person's own "persons, houses, papers, and effects."

Katz did not abandon reliance on property-based concepts. The Court in Katz analogized the phone booth used in that case to a friend's apartment, a taxicab, and a hotel room. 389 U.S., at 352, 359, 88 S.Ct. 507. So when the defendant "shu[t] the door behind him" and "pa[id] the toll," id., at 352, 88 S.Ct. 507, he had a temporary interest in the space and a legitimate expectation that others would not intrude, much like the interest a hotel guest has in a hotel room, *2228Stoner v. California, 376 U.S. 483, 84 S.Ct. 889, 11 L.Ed.2d 856 (1964), or an overnight guest has in a host's home, Minnesota v. Olson, 495 U.S. 91, 110 S.Ct. 1684, 109 L.Ed.2d 85 (1990). The Government intruded on that space when it attached a listening device to the phone booth. Katz, 389 U.S., at 348, 88 S.Ct. 507. (And even so, the Court made it clear that the Government's search could have been reasonable had there been judicial approval on a case-specific basis, which, of course, did occur here. Id ., at 357-359, 88 S.Ct. 507.)

Miller and Smith set forth an important and necessary limitation on the Katz framework. They rest upon the commonsense principle that the absence of property law analogues can be dispositive of privacy expectations. The defendants in those cases could expect that the third-party businesses could use the records the companies collected, stored, and classified as their own for any number of business and commercial purposes. The businesses were not bailees or custodians of the records, with a duty to hold the records for the defendants' use. The defendants could make no argument that the records were their own papers or effects. See Miller, supra, at 440, 96 S.Ct. 1619 ("the documents subpoenaed here are not respondent's 'private papers' "); Smith, supra, at 741, 99 S.Ct. 2577 ("petitioner obviously cannot claim that his 'property' was invaded"). The records were the business entities' records, plain and simple. The defendants had no reason to believe the records were owned or controlled by them and so could not assert a reasonable expectation of privacy in the records.

The second principle supporting Miller and Smith is the longstanding rule that the Government may use compulsory process to compel persons to disclose documents and other evidence within their possession and control. See United States v. Nixon, 418 U.S. 683, 709, 94 S.Ct. 3090, 41 L.Ed.2d 1039 (1974) (it is an "ancient proposition of law" that "the public has a right to every man's evidence" (internal quotation marks and alterations omitted)). A subpoena is different from a warrant in its force and intrusive power. While a warrant allows the Government to enter and seize and make the examination itself, a subpoena simply requires the person to whom it is directed to make the disclosure. A subpoena, moreover, provides the recipient the "opportunity to present objections" before complying, which further mitigates the intrusion. Oklahoma Press Publishing Co. v. Walling, 327 U.S. 186, 195, 66 S.Ct. 494, 90 L.Ed. 614 (1946).

For those reasons this Court has held that a subpoena for records, although a "constructive" search subject to Fourth Amendment constraints, need not comply with the procedures applicable to warrants-even when challenged by the person to whom the records belong. Id., at 202, 208, 66 S.Ct. 494. Rather, a subpoena complies with the Fourth Amendment's reasonableness requirement so long as it is " 'sufficiently limited in scope, relevant in purpose, and specific in directive so that compliance will not be unreasonably burdensome.' " Donovan v. Lone Steer, Inc., 464 U.S. 408, 415, 104 S.Ct. 769, 78 L.Ed.2d 567 (1984). Persons with no meaningful interests in the records sought by a subpoena, like the defendants in Miller and Smith, have no rights to object to the records' disclosure-much less to assert that the Government must obtain a warrant to compel disclosure of the records. See Miller, 425 U.S., at 444-446, 96 S.Ct. 1619 ; SEC v. Jerry T. O'Brien, Inc., 467 U.S. 735, 742-743, 104 S.Ct. 2720, 81 L.Ed.2d 615 (1984).

Based on Miller and Smith and the principles underlying those cases, it is well established that subpoenas may be used to *2229obtain a wide variety of records held by businesses, even when the records contain private information. See 2 W. LaFave, Search and Seizure § 4.13 (5th ed. 2012). Credit cards are a prime example. State and federal law enforcement, for instance, often subpoena credit card statements to develop probable cause to prosecute crimes ranging from drug trafficking and distribution to healthcare fraud to tax evasion. See United States v. Phibbs, 999 F.2d 1053 (C.A.6 1993) (drug distribution); McCune v. DOJ, 592 Fed.Appx. 287 (C.A.5 2014) (healthcare fraud); United States v. Green, 305 F.3d 422 (C.A.6 2002) (drug trafficking and tax evasion); see also 12 U.S.C. §§ 3402(4), 3407 (allowing the Government to subpoena financial records if "there is reason to believe that the records sought are relevant to a legitimate law enforcement inquiry"). Subpoenas also may be used to obtain vehicle registration records, hotel records, employment records, and records of utility usage, to name just a few other examples. See 1 LaFave, supra, § 2.7(c).

And law enforcement officers are not alone in their reliance on subpoenas to obtain business records for legitimate investigations. Subpoenas also are used for investigatory purposes by state and federal grand juries, see United States v. Dionisio, 410 U.S. 1, 93 S.Ct. 764, 35 L.Ed.2d 67 (1973), state and federal administrative agencies, see Oklahoma Press, supra, and state and federal legislative bodies, see McPhaul v. United States, 364 U.S. 372, 81 S.Ct. 138, 5 L.Ed.2d 136 (1960).

B

Carpenter does not question these traditional investigative practices. And he does not ask the Court to reconsider Miller and Smith . Carpenter argues only that, under Miller and Smith, the Government may not use compulsory process to acquire cell-site records from cell phone service providers.

There is no merit in this argument. Cell-site records, like all the examples just discussed, are created, kept, classified, owned, and controlled by cell phone service providers, which aggregate and sell this information to third parties. As in Miller, Carpenter can "assert neither ownership nor possession" of the records and has no control over them. 425 U.S., at 440, 96 S.Ct. 1619.

Carpenter argues that he has Fourth Amendment interests in the cell-site records because they are in essence his personal papers by operation of 47 U.S.C. § 222. That statute imposes certain restrictions on how providers may use "customer proprietary network information"-a term that encompasses cell-site records. §§ 222(c), (h)(1)(A). The statute in general prohibits providers from disclosing personally identifiable cell-site records to private third parties. § 222(c)(1). And it allows customers to request cell-site records from the provider. § 222(c)(2).

Carpenter's argument is unpersuasive, however, for § 222 does not grant cell phone customers any meaningful interest in cell-site records. The statute's confidentiality protections may be overridden by the interests of the providers or the Government. The providers may disclose the records "to protect the[ir] rights or property" or to "initiate, render, bill, and collect for telecommunications services." §§ 222(d)(1), (2). They also may disclose the records "as required by law"-which, of course, is how they were disclosed in this case. § 222(c)(1). Nor does the statute provide customers any practical control over the records. Customers do not create the records; they have no say in whether or for how long the records are stored; and they cannot require the records to be modified or destroyed. Even *2230their right to request access to the records is limited, for the statute "does not preclude a carrier from being reimbursed by the customers ... for the costs associated with making such disclosures." H.R.Rep. No. 104-204, pt. 1, p. 90 (1995). So in every legal and practical sense the "network information" regulated by § 222 is, under that statute, "proprietary" to the service providers, not Carpenter. The Court does not argue otherwise.

Because Carpenter lacks a requisite connection to the cell-site records, he also may not claim a reasonable expectation of privacy in them. He could expect that a third party-the cell phone service provider-could use the information it collected, stored, and classified as its own for a variety of business and commercial purposes.

All this is not to say that Miller and Smith are without limits. Miller and Smith may not apply when the Government obtains the modern-day equivalents of an individual's own "papers" or "effects," even when those papers or effects are held by a third party. See Ex parte Jackson, 96 U.S. 727, 733, 24 L.Ed. 877 (1878) (letters held by mail carrier); United States v. Warshak, 631 F.3d 266, 283-288 (C.A.6 2010) (e-mails held by Internet service provider). As already discussed, however, this case does not involve property or a bailment of that sort. Here the Government's acquisition of cell-site records falls within the heartland of Miller and Smith .

In fact, Carpenter's Fourth Amendment objection is even weaker than those of the defendants in Miller and Smith . Here the Government did not use a mere subpoena to obtain the cell-site records. It acquired the records only after it proved to a Magistrate Judge reasonable grounds to believe that the records were relevant and material to an ongoing criminal investigation. See 18 U.S.C. § 2703(d). So even if § 222 gave Carpenter some attenuated interest in the records, the Government's conduct here would be reasonable under the standards governing subpoenas. See Donovan, 464 U.S., at 415, 104 S.Ct. 769.

Under Miller and Smith, then, a search of the sort that requires a warrant simply did not occur when the Government used court-approved compulsory process, based on a finding of reasonable necessity, to compel a cell phone service provider, as owner, to disclose cell-site records.

III

The Court rejects a straightforward application of Miller and Smith . It concludes instead that applying those cases to cell-site records would work a "significant extension" of the principles underlying them, ante, at 2219, and holds that the acquisition of more than six days of cell-site records constitutes a search, ante, at 2217, n. 3.

In my respectful view the majority opinion misreads this Court's precedents, old and recent, and transforms Miller and Smith into an unprincipled and unworkable doctrine. The Court's newly conceived constitutional standard will cause confusion; will undermine traditional and important law enforcement practices; and will allow the cell phone to become a protected medium that dangerous persons will use to commit serious crimes.

A

The Court errs at the outset by attempting to sidestep Miller and Smith . The Court frames this case as following instead from United States v. Knotts, 460 U.S. 276, 103 S.Ct. 1081, 75 L.Ed.2d 55 (1983), and United States v. Jones, 565 U.S. 400, 132 S.Ct. 945, 181 L.Ed.2d 911 (2012). Those cases, the Court suggests, establish that *2231"individuals have a reasonable expectation of privacy in the whole of their physical movements." Ante, at 2214 - 2216, 2217.

Knotts held just the opposite: "A person traveling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another." 460 U.S., at 281, 103 S.Ct. 1081. True, the Court in Knotts also suggested that "different constitutional principles may be applicable" to "dragnet-type law enforcement practices." Id., at 284, 103 S.Ct. 1081. But by dragnet practices the Court was referring to " 'twenty-four hour surveillance of any citizen of this country ... without judicial knowledge or supervision.' " Id., at 283, 103 S.Ct. 1081.

Those "different constitutional principles" mentioned in Knotts, whatever they may be, do not apply in this case. Here the Stored Communications Act requires a neutral judicial officer to confirm in each case that the Government has "reasonable grounds to believe" the cell-site records "are relevant and material to an ongoing criminal investigation." 18 U.S.C. § 2703(d). This judicial check mitigates the Court's concerns about " 'a too permeating police surveillance.' " Ante, at 2214 (quoting United States v. Di Re, 332 U.S. 581, 595, 68 S.Ct. 222, 92 L.Ed. 210 (1948) ). Here, even more so than in Knotts, "reality hardly suggests abuse." 460 U.S., at 284, 103 S.Ct. 1081.

The Court's reliance on Jones fares no better. In Jones the Government installed a GPS tracking device on the defendant's automobile. The Court held the Government searched the automobile because it "physically occupied private property [of the defendant] for the purpose of obtaining information." 565 U.S., at 404, 132 S.Ct. 945. So in Jones it was "not necessary to inquire about the target's expectation of privacy in his vehicle's movements." Grady v. North Carolina, 575 U.S. ----, ----, 135 S.Ct. 1368, 1370, 191 L.Ed.2d 459 (2015) (per curiam ).

Despite that clear delineation of the Court's holding in Jones, the Court today declares that Jones applied the " 'different constitutional principles' " alluded to in Knotts to establish that an individual has an expectation of privacy in the sum of his whereabouts. Ante, at 2215, 2217 - 2218. For that proposition the majority relies on the two concurring opinions in Jones, one of which stated that "longer term GPS monitoring in investigations of most offenses impinges on expectations of privacy." 565 U.S., at 430, 132 S.Ct. 945 (ALITO, J., concurring). But Jones involved direct governmental surveillance of a defendant's automobile without judicial authorization-specifically, GPS surveillance accurate within 50 to 100 feet. Id., at 402-403, 132 S.Ct. 945. Even assuming that the different constitutional principles mentioned in Knotts would apply in a case like Jones -a proposition the Court was careful not to announce in Jones, supra, at 412-413, 132 S.Ct. 945 -those principles are inapplicable here. Cases like this one, where the Government uses court-approved compulsory process to obtain records owned and controlled by a third party, are governed by the two majority opinions in Miller and Smith .

B

The Court continues its analysis by misinterpreting Miller and Smith, and then it reaches the wrong outcome on these facts even under its flawed standard.

The Court appears, in my respectful view, to read Miller and Smith to establish a balancing test. For each "qualitatively different category" of information, the Court suggests, the privacy interests at stake must be weighed against the fact that the information has been disclosed to a third party. See *2232ante, at 2216, 2219 - 2220. When the privacy interests are weighty enough to "overcome" the third-party disclosure, the Fourth Amendment's protections apply. See ante, at 2220.

That is an untenable reading of Miller and Smith . As already discussed, the fact that information was relinquished to a third party was the entire basis for concluding that the defendants in those cases lacked a reasonable expectation of privacy. Miller and Smith do not establish the kind of category-by-category balancing the Court today prescribes.

But suppose the Court were correct to say that Miller and Smith rest on so imprecise a foundation. Still the Court errs, in my submission, when it concludes that cell-site records implicate greater privacy interests-and thus deserve greater Fourth Amendment protection-than financial records and telephone records.

Indeed, the opposite is true. A person's movements are not particularly private. As the Court recognized in Knotts, when the defendant there "traveled over the public streets he voluntarily conveyed to anyone who wanted to look the fact that he was traveling over particular roads in a particular direction, the fact of whatever stops he made, and the fact of his final destination." 460 U.S., at 281-282, 103 S.Ct. 1081. Today expectations of privacy in one's location are, if anything, even less reasonable than when the Court decided Knotts over 30 years ago. Millions of Americans choose to share their location on a daily basis, whether by using a variety of location-based services on their phones, or by sharing their location with friends and the public at large via social media.

And cell-site records, as already discussed, disclose a person's location only in a general area. The records at issue here, for example, revealed Carpenter's location within an area covering between around a dozen and several hundred city blocks. "Areas of this scale might encompass bridal stores and Bass Pro Shops, gay bars and straight ones, a Methodist church and the local mosque." 819 F.3d 880, 889 (C.A.6 2016). These records could not reveal where Carpenter lives and works, much less his " 'familial, political, professional, religious, and sexual associations.' " Ante, at 2217 (quoting Jones, supra, at 415, 132 S.Ct. 945 (SOTOMAYOR, J., concurring)).

By contrast, financial records and telephone records do " 'revea[l] ... personal affairs, opinions, habits and associations.' " Miller, 425 U.S., at 451, 96 S.Ct. 1619 (Brennan, J., dissenting); see Smith, 442 U.S., at 751, 99 S.Ct. 2577 (Marshall, J., dissenting). What persons purchase and to whom they talk might disclose how much money they make; the political and religious organizations to which they donate; whether they have visited a psychiatrist, plastic surgeon, abortion clinic, or AIDS treatment center; whether they go to gay bars or straight ones; and who are their closest friends and family members. The troves of intimate information the Government can and does obtain using financial records and telephone records dwarfs what can be gathered from cell-site records.

Still, the Court maintains, cell-site records are "unique" because they are "comprehensive" in their reach; allow for retrospective collection; are "easy, cheap, and efficient compared to traditional investigative tools"; and are not exposed to cell phone service providers in a meaningfully voluntary manner. Ante, at 2216 - 2218, 2220, 2223. But many other kinds of business records can be so described. Financial records are of vast scope. Banks and credit card companies keep a comprehensive account of almost every transaction an individual makes on a daily basis. "With *2233just the click of a button, the Government can access each [company's] deep repository of historical [financial] information at practically no expense." Ante, at 2218. And the decision whether to transact with banks and credit card companies is no more or less voluntary than the decision whether to use a cell phone. Today, just as when Miller was decided, " 'it is impossible to participate in the economic life of contemporary society without maintaining a bank account.' " 425 U.S., at 451, 96 S.Ct. 1619 (BRENNAN, J., dissenting). But this Court, nevertheless, has held that individuals do not have a reasonable expectation of privacy in financial records.

Perhaps recognizing the difficulty of drawing the constitutional line between cell-site records and financial and telephonic records, the Court posits that the accuracy of cell-site records "is rapidly approaching GPS-level precision." Ante, at 2219. That is certainly plausible in the era of cyber technology, yet the privacy interests associated with location information, which is often disclosed to the public at large, still would not outweigh the privacy interests implicated by financial and telephonic records.

Perhaps more important, those future developments are no basis upon which to resolve this case. In general, the Court "risks error by elaborating too fully on the Fourth Amendment implications of emerging technology before its role in society has become clear." Ontario v. Quon, 560 U.S. 746, 759, 130 S.Ct. 2619, 177 L.Ed.2d 216 (2010). That judicial caution, prudent in most cases, is imperative in this one.

Technological changes involving cell phones have complex effects on crime and law enforcement. Cell phones make crimes easier to coordinate and conceal, while also providing the Government with new investigative tools that may have the potential to upset traditional privacy expectations. See Kerr, An Equilibrium-Adjustment Theory of the Fourth Amendment, 125 Harv. L. Rev 476, 512-517 (2011). How those competing effects balance against each other, and how property norms and expectations of privacy form around new technology, often will be difficult to determine during periods of rapid technological change. In those instances, and where the governing legal standard is one of reasonableness, it is wise to defer to legislative judgments like the one embodied in § 2703(d) of the Stored Communications Act. See Jones, 565 U.S., at 430, 132 S.Ct. 945 (ALITO, J., concurring). In § 2703(d) Congress weighed the privacy interests at stake and imposed a judicial check to prevent executive overreach. The Court should be wary of upsetting that legislative balance and erecting constitutional barriers that foreclose further legislative instructions. See Quon, supra, at 759, 130 S.Ct. 2619. The last thing the Court should do is incorporate an arbitrary and outside limit-in this case six days' worth of cell-site records-and use it as the foundation for a new constitutional framework. The Court's decision runs roughshod over the mechanism Congress put in place to govern the acquisition of cell-site records and closes off further legislative debate on these issues.

C

The Court says its decision is a "narrow one." Ante, at 2220. But its reinterpretation of Miller and Smith will have dramatic consequences for law enforcement, courts, and society as a whole.

Most immediately, the Court's holding that the Government must get a warrant to obtain more than six days of cell-site records limits the effectiveness of an important investigative tool for solving serious crimes. As this case demonstrates, cell-site records are uniquely suited to help *2234the Government develop probable cause to apprehend some of the Nation's most dangerous criminals: serial killers, rapists, arsonists, robbers, and so forth. See also, e.g., Davis, 785 F.3d, at 500-501 (armed robbers); Brief for Alabama et al. as Amici Curiae 21-22 (serial killer). These records often are indispensable at the initial stages of investigations when the Government lacks the evidence necessary to obtain a warrant. See United States v. Pembrook, 876 F.3d 812, 816-819 (C.A.6 2017). And the long-term nature of many serious crimes, including serial crimes and terrorism offenses, can necessitate the use of significantly more than six days of cell-site records. The Court's arbitrary 6-day cutoff has the perverse effect of nullifying Congress' reasonable framework for obtaining cell-site records in some of the most serious criminal investigations.

The Court's decision also will have ramifications that extend beyond cell-site records to other kinds of information held by third parties, yet the Court fails "to provide clear guidance to law enforcement" and courts on key issues raised by its reinterpretation of Miller and Smith . Riley v. California, 573 U.S. ----, ----, 134 S.Ct. 2473, 2491, 189 L.Ed.2d 430 (2014).

First, the Court's holding is premised on cell-site records being a "distinct category of information" from other business records. Ante, at 2219. But the Court does not explain what makes something a distinct category of information. Whether credit card records are distinct from bank records; whether payment records from digital wallet applications are distinct from either; whether the electronic bank records available today are distinct from the paper and microfilm records at issue in Miller ; or whether cell-phone call records are distinct from the home-phone call records at issue in Smith, are just a few of the difficult questions that require answers under the Court's novel conception of Miller and Smith .

Second, the majority opinion gives courts and law enforcement officers no indication how to determine whether any particular category of information falls on the financial-records side or the cell-site-records side of its newly conceived constitutional line. The Court's multifactor analysis-considering intimacy, comprehensiveness, expense, retrospectivity, and voluntariness-puts the law on a new and unstable foundation.

Third, even if a distinct category of information is deemed to be more like cell-site records than financial records, courts and law enforcement officers will have to guess how much of that information can be requested before a warrant is required. The Court suggests that less than seven days of location information may not require a warrant. See ante, at 2217, n. 3; see also ante, at 2220 - 2221 (expressing no opinion on "real-time CSLI," tower dumps, and security-camera footage). But the Court does not explain why that is so, and nothing in its opinion even alludes to the considerations that should determine whether greater or lesser thresholds should apply to information like IP addresses or website browsing history.

Fourth, by invalidating the Government's use of court-approved compulsory process in this case, the Court calls into question the subpoena practices of federal and state grand juries, legislatures, and other investigative bodies, as Justice ALITO's opinion explains. See post, at 2247 - 2257 (dissenting opinion). Yet the Court fails even to mention the serious consequences this will have for the proper administration of justice.

In short, the Court's new and uncharted course will inhibit law enforcement and "keep defendants and judges guessing for years to come."

*2235Riley, 573 U.S., at ----, 134 S.Ct., at 2493 (internal quotation marks omitted).

* * *

This case should be resolved by interpreting accepted property principles as the baseline for reasonable expectations of privacy. Here the Government did not search anything over which Carpenter could assert ownership or control. Instead, it issued a court-authorized subpoena to a third party to disclose information it alone owned and controlled. That should suffice to resolve this case.

Having concluded, however, that the Government searched Carpenter when it obtained cell-site records from his cell phone service providers, the proper resolution of this case should have been to remand for the Court of Appeals to determine in the first instance whether the search was reasonable. Most courts of appeals, believing themselves bound by Miller and Smith, have not grappled with this question. And the Court's reflexive imposition of the warrant requirement obscures important and difficult issues, such as the scope of Congress' power to authorize the Government to collect new forms of information using processes that deviate from traditional warrant procedures, and how the Fourth Amendment's reasonableness requirement should apply when the Government uses compulsory process instead of engaging in an actual, physical search.

These reasons all lead to this respectful dissent.

APPENDIX

'' § 2703. Required disclosure of customer communications or records

"(d) REQUIREMENTS FOR COURT ORDER .-A court order for disclosure under subsection (b) or (c) may be issued by any court that is a court of competent jurisdiction and shall issue only if the governmental entity offers specific and articulable facts showing that there are reasonable grounds to believe that the contents of a wire or electronic communication, or the records or other information sought, are relevant and material to an ongoing criminal investigation. In the case of a State governmental authority, such a court order shall not issue if prohibited by the law of such State. A court issuing an order pursuant to this section, on a motion made promptly by the service provider, may quash or modify such order, if the information or records requested are unusually voluminous in nature or compliance with such order otherwise would cause an undue burden on such provider."

Justice THOMAS, dissenting.

This case should not turn on "whether" a search occurred. Ante, at 2223 - 2224. It should turn, instead, on whose property was searched. The Fourth Amendment guarantees individuals the right to be secure from unreasonable searches of "their persons, houses, papers, and effects." (Emphasis added.) In other words, "each person has the right to be secure against unreasonable searches ... in his own person, house, papers, and effects." Minnesota v. Carter, 525 U.S. 83, 92, 119 S.Ct. 469, 142 L.Ed.2d 373 (1998) (Scalia, J., concurring). By obtaining the cell-site records of MetroPCS and Sprint, the Government did not search Carpenter's property. He did not create the records, he does not maintain them, he cannot control them, and he cannot destroy them. Neither the terms of his contracts nor any provision of law makes the records his. The records belong to MetroPCS and Sprint.

The Court concludes that, although the records are not Carpenter's, the Government must get a warrant because Carpenter had a reasonable "expectation of privacy"

*2236in the location information that they reveal. Ante, at 2216 - 2217. I agree with Justice KENNEDY, Justice ALITO, Justice GORSUCH, and every Court of Appeals to consider the question that this is not the best reading of our precedents.

The more fundamental problem with the Court's opinion, however, is its use of the "reasonable expectation of privacy" test, which was first articulated by Justice Harlan in Katz v. United States, 389 U.S. 347, 360-361, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967) (concurring opinion). The Katz test has no basis in the text or history of the Fourth Amendment. And, it invites courts to make judgments about policy, not law. Until we confront the problems with this test, Katz will continue to distort Fourth Amendment jurisprudence. I respectfully dissent.

I

Katz was the culmination of a series of decisions applying the Fourth Amendment to electronic eavesdropping. The first such decision was Olmstead v. United States, 277 U.S. 438, 48 S.Ct. 564, 72 L.Ed. 944 (1928), where federal officers had intercepted the defendants' conversations by tapping telephone lines near their homes. Id., at 456-457, 48 S.Ct. 564. In an opinion by Chief Justice Taft, the Court concluded that this wiretap did not violate the Fourth Amendment. No "search" occurred, according to the Court, because the officers did not physically enter the defendants' homes. Id., at 464-466, 48 S.Ct. 564. And neither the telephone lines nor the defendants' intangible conversations qualified as "persons, houses, papers, [or] effects" within the meaning of the Fourth Amendment. Ibid.1 In the ensuing decades, this Court adhered to Olmstead and rejected Fourth Amendment challenges to various methods of electronic surveillance. See On Lee v. United States, 343 U.S. 747, 749-753, 72 S.Ct. 967, 96 L.Ed. 1270 (1952) (use of microphone to overhear conversations with confidential informant); Goldman v. United States, 316 U.S. 129, 131-132, 135-136, 62 S.Ct. 993, 86 L.Ed. 1322 (1942) (use of detectaphone to hear conversations in office next door).

In the 1960's, however, the Court began to retreat from Olmstead . In Silverman v. United States, 365 U.S. 505, 81 S.Ct. 679, 5 L.Ed.2d 734 (1961), for example, federal officers had eavesdropped on the defendants by driving a "spike mike" several inches into the house they were occupying. Id., at 506-507, 81 S.Ct. 679. This was a "search," the Court held, because the "unauthorized physical penetration into the premises" was an "actual intrusion into a constitutionally protected area." Id., at 509, 512, 81 S.Ct. 679. The Court did not mention Olmstead 's other holding that intangible conversations are not "persons, houses, papers, [or] effects." That omission was significant. The Court confirmed two years later that "[i]t follows from [Silverman ] that the Fourth Amendment may protect against the overhearing of verbal statements as well as against the more traditional seizure of 'papers and effects.' " Wong Sun v. United States, 371 U.S. 471, 485, 83 S.Ct. 407, 9 L.Ed.2d 441 (1963) ; accord, *2237Berger v. New York, 388 U.S. 41, 51, 87 S.Ct. 1873, 18 L.Ed.2d 1040 (1967).

In Katz, the Court rejected Olmstead 's remaining holding-that eavesdropping is not a search absent a physical intrusion into a constitutionally protected area. The federal officers in Katz had intercepted the defendant's conversations by attaching an electronic device to the outside of a public telephone booth. 389 U.S., at 348, 88 S.Ct. 507. The Court concluded that this was a "search" because the officers "violated the privacy upon which [the defendant] justifiably relied while using the telephone booth." Id., at 353, 88 S.Ct. 507. Although the device did not physically penetrate the booth, the Court overruled Olmstead and held that "the reach of [the Fourth] Amendment cannot turn upon the presence or absence of a physical intrusion." 389 U.S., at 353, 88 S.Ct. 507. The Court did not explain what should replace Olmstead 's physical-intrusion requirement. It simply asserted that "the Fourth Amendment protects people, not places" and "what [a person] seeks to preserve as private ... may be constitutionally protected." 389 U.S., at 351, 88 S.Ct. 507.

Justice Harlan's concurrence in Katz attempted to articulate the standard that was missing from the majority opinion. While Justice Harlan agreed that " 'the Fourth Amendment protects people, not places,' " he stressed that "[t]he question ... is what protection it affords to those people," and "the answer ... requires reference to a 'place.' " Id., at 361, 88 S.Ct. 507. Justice Harlan identified a "twofold requirement" to determine when the protections of the Fourth Amendment apply: "first that a person have exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognize as 'reasonable.' " Ibid.

Justice Harlan did not cite anything for this "expectation of privacy" test, and the parties did not discuss it in their briefs. The test appears to have been presented for the first time at oral argument by one of the defendant's lawyers. See Winn, Katz and the Origins of the "Reasonable Expectation of Privacy" Test, 40 McGeorge L. Rev. 1, 9-10 (2009). The lawyer, a recent law-school graduate, apparently had an "[e]piphany" while preparing for oral argument. Schneider, Katz v. United States : The Untold Story, 40 McGeorge L. Rev. 13, 18 (2009). He conjectured that, like the "reasonable person" test from his Torts class, the Fourth Amendment should turn on "whether a reasonable person ... could have expected his communication to be private." Id., at 19. The lawyer presented his new theory to the Court at oral argument. See, e.g., Tr. of Oral Arg. in Katz v. United States, O.T. 1967, No. 35, p. 5 (proposing a test of "whether or not, objectively speaking, the communication was intended to be private"); id., at 11 ("We propose a test using a way that's not too dissimilar from the tort 'reasonable man' test"). After some questioning from the Justices, the lawyer conceded that his test should also require individuals to subjectively expect privacy. See id., at 12. With that modification, Justice Harlan seemed to accept the lawyer's test almost verbatim in his concurrence.

Although the majority opinion in Katz had little practical significance after Congress enacted the Omnibus Crime Control and Safe Streets Act of 1968, Justice Harlan's concurrence profoundly changed our Fourth Amendment jurisprudence. It took only one year for the full Court to adopt his two-pronged test. See Terry v. Ohio, 392 U.S. 1, 10, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968). And by 1979, the Court was describing Justice Harlan's test as the "lodestar" for determining whether *2238a "search" had occurred. Smith v. Maryland, 442 U.S. 735, 739, 99 S.Ct. 2577, 61 L.Ed.2d 220 (1979). Over time, the Court minimized the subjective prong of Justice Harlan's test. See Kerr, Katz Has Only One Step: The Irrelevance of Subjective Expectations, 82 U. Chi. L. Rev. 113 (2015). That left the objective prong-the "reasonable expectation of privacy" test that the Court still applies today. See ante, at 2213 - 2214; United States v. Jones, 565 U.S. 400, 406, 132 S.Ct. 945, 181 L.Ed.2d 911 (2012).

II

Under the Katz test, a "search" occurs whenever "government officers violate a person's 'reasonable expectation of privacy.' " Jones, supra, at 406, 132 S.Ct. 945. The most glaring problem with this test is that it has "no plausible foundation in the text of the Fourth Amendment." Carter, 525 U.S., at 97, 119 S.Ct. 469 (opinion of Scalia, J.). The Fourth Amendment, as relevant here, protects "[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches." By defining "search" to mean "any violation of a reasonable expectation of privacy," the Katz test misconstrues virtually every one of these words.

A

The Katz test distorts the original meaning of "searc[h]"-the word in the Fourth Amendment that it purports to define, see ante, at 2213 - 2214; Smith, supra . Under the Katz test, the government conducts a search anytime it violates someone's "reasonable expectation of privacy." That is not a normal definition of the word "search."

At the founding, "search" did not mean a violation of someone's reasonable expectation of privacy. The word was probably not a term of art, as it does not appear in legal dictionaries from the era. And its ordinary meaning was the same as it is today: " '[t]o look over or through for the purpose of finding something; to explore; to examine by inspection; as, to search the house for a book; to search the wood for a thief.' " Kyllo v. United States, 533 U.S. 27, 32, n. 1, 121 S.Ct. 2038, 150 L.Ed.2d 94 (2001) (quoting N. Webster, An American Dictionary of the English Language 66 (1828) (reprint 6th ed. 1989)); accord, 2 S. Johnson, A Dictionary of the English Language (5th ed. 1773) ("Inquiry by looking into every suspected place"); N. Bailey, An Universal Etymological English Dictionary (22d ed. 1770) ("a seeking after, a looking for, & c."); 2 J. Ash, The New and Complete Dictionary of the English Language (2d ed. 1795) ("An enquiry, an examination, the act of seeking, an enquiry by looking into every suspected place; a quest; a pursuit"); T. Sheridan, A Complete Dictionary of the English Language (6th ed. 1796) (similar). The word "search" was not associated with "reasonable expectation of privacy" until Justice Harlan coined that phrase in 1967. The phrase "expectation(s) of privacy" does not appear in the pre-Katz federal or state case reporters, the papers of prominent Founders,2 early congressional documents and debates,3 collections of early American English texts,4 or early American newspapers.

*22395

B

The Katz test strays even further from the text by focusing on the concept of "privacy." The word "privacy" does not appear in the Fourth Amendment (or anywhere else in the Constitution for that matter). Instead, the Fourth Amendment references "[t]he right of the people to be secure." It then qualifies that right by limiting it to "persons" and three specific types of property: "houses, papers, and effects." By connecting the right to be secure to these four specific objects, "[t]he text of the Fourth Amendment reflects its close connection to property." Jones, supra, at 405, 132 S.Ct. 945. "[P]rivacy," by contrast, "was not part of the political vocabulary of the [founding]. Instead, liberty and privacy rights were understood largely in terms of property rights." Cloud, Property Is Privacy: Locke and Brandeis in the Twenty-First Century, 55 Am. Crim. L. Rev. 37, 42 (2018).

Those who ratified the Fourth Amendment were quite familiar with the notion of security in property. Security in property was a prominent concept in English law. See, e.g., 3 W. Blackstone, Commentaries on the Laws of England 288 (1768) ("[E]very man's house is looked upon by the law to be his castle"); 3 E. Coke, Institutes of Laws of England 162 (6th ed. 1680) ("[F]or a man[']s house is his Castle, & domus sua cuique est tutissimum refugium [each man's home is his safest refuge]"). The political philosophy of John Locke, moreover, "permeated the 18th-century political scene in America." Obergefell v. Hodges, 576 U.S. ----, ----, 135 S.Ct. 2584, 2634, 192 L.Ed.2d 609 (2015) (THOMAS, J., dissenting). For Locke, every individual had a property right "in his own person" and in anything he "removed from the common state [of] Nature" and "mixed his labour with." Second Treatise of Civil Government § 27 (1690). Because property is "very unsecure" in the state of nature, § 123, individuals form governments to obtain "a secure enjoyment of their properties." § 95. Once a government is formed, however, it cannot be given "a power to destroy that which every one designs to secure"; it cannot legitimately "endeavour to take away, and destroy the property of the people," or exercise "an absolute power over [their] lives, liberties, and estates." § 222.

The concept of security in property recognized by Locke and the English legal tradition appeared throughout the materials that inspired the Fourth Amendment. In Entick v. Carrington, 19 How. St. Tr. 1029 (C.P. 1765)-a heralded decision that the founding generation considered "the true and ultimate expression of constitutional law," Boyd v. United States, 116 U.S. 616, 626, 6 S.Ct. 524, 29 L.Ed. 746 (1886) -Lord Camden explained that "[t]he great end, for which men entered into society, was to secure their property." 19 How. St. Tr., at 1066. The American colonists echoed this reasoning in their "widespread hostility" to the Crown's writs of assistance6 -a practice that inspired the Revolution and became "[t]he driving force behind the adoption of the [Fourth] Amendment."

*2240United States v. Verdugo-Urquidez, 494 U.S. 259, 266, 110 S.Ct. 1056, 108 L.Ed.2d 222 (1990). Prominent colonists decried the writs as destroying " 'domestic security' " by permitting broad searches of homes. M. Smith, The Writs of Assistance Case 475 (1978) (quoting a 1772 Boston town meeting); see also id., at 562 (complaining that " 'every householder in this province, will necessarily become less secure than he was before this writ' " (quoting a 1762 article in the Boston Gazette)); id., at 493 (complaining that the writs were " 'expressly contrary to the common law, which ever regarded a man's house as his castle, or a place of perfect security' " (quoting a 1768 letter from John Dickinson)). John Otis, who argued the famous Writs of Assistance case, contended that the writs violated " 'the fundamental Principl[e] of Law' " that " '[a] Man who is quiet, is as secure in his House, as a Prince in his Castle.' " Id., at 339 (quoting John Adam's notes). John Adams attended Otis' argument and later drafted Article XIV of the Massachusetts Constitution,7 which served as a model for the Fourth Amendment. See Clancy, The Framers' Intent: John Adams, His Era, and the Fourth Amendment, 86 Ind. L.J. 979, 982 (2011) ; Donahue, The Original Fourth Amendment, 83 U. Chi. L. Rev. 1181, 1269 (2016) (Donahue). Adams agreed that "[p]roperty must be secured, or liberty cannot exist." Discourse on Davila, in 6 The Works of John Adams 280 (C. Adams ed. 1851).

Of course, the founding generation understood that, by securing their property, the Fourth Amendment would often protect their privacy as well. See, e.g., Boyd, supra, at 630, 6 S.Ct. 524 (explaining that searches of houses invade "the privacies of life"); Wilkes v. Wood, 19 How. St. Tr. 1153, 1154 (C.P. 1763) (argument of counsel contending that seizures of papers implicate "our most private concerns"). But the Fourth Amendment's attendant protection of privacy does not justify Katz 's elevation of privacy as the sine qua non of the Amendment. See T. Clancy, The Fourth Amendment: Its History and Interpretation § 3.4.4, p. 78 (2008) ("[The Katz test] confuse[s] the reasons for exercising the protected right with the right itself. A purpose of exercising one's Fourth Amendment rights might be the desire for privacy, but the individual's motivation is not the right protected"); cf. United States v. Gonzalez-Lopez, 548 U.S. 140, 145, 126 S.Ct. 2557, 165 L.Ed.2d 409 (2006) (rejecting "a line of reasoning that 'abstracts from the right to its purposes, and then eliminates the right' "). As the majority opinion in Katz recognized, the Fourth Amendment "cannot be translated into a general constitutional 'right to privacy,' " as its protections "often have nothing to do with privacy at all." 389 U.S., at 350, 88 S.Ct. 507. Justice Harlan's focus on privacy in his concurrence-an opinion that was issued between Griswold v. Connecticut, 381 U.S. 479, 85 S.Ct. 1678, 14 L.Ed.2d 510 (1965), and Roe v. Wade, 410 U.S. 113, 93 S.Ct. 705, 35 L.Ed.2d 147 (1973) -reflects privacy's status as the organizing constitutional idea of the 1960's and 1970's. The organizing constitutional idea of the founding era, by contrast, was property.

*2241C

In shifting the focus of the Fourth Amendment from property to privacy, the Katz test also reads the words "persons, houses, papers, and effects" out of the text. At its broadest formulation, the Katz test would find a search "wherever an individual may harbor a reasonable 'expectation of privacy.' " Terry, 392 U.S., at 9, 88 S.Ct. 1868 (emphasis added). The Court today, for example, does not ask whether cell-site location records are "persons, houses, papers, [or] effects" within the meaning of the Fourth Amendment.8 Yet "persons, houses, papers, and effects" cannot mean "anywhere" or "anything." Katz 's catchphrase that "the Fourth Amendment protects people, not places," is not a serious attempt to reconcile the constitutional text. See Carter, 525 U.S., at 98, n. 3, 119 S.Ct. 469 (opinion of Scalia, J.). The Fourth Amendment obviously protects people; "[t]he question ... is what protection it affords to those people." Katz, 389 U.S., at 361, 88 S.Ct. 507 (Harlan, J., concurring). The Founders decided to protect the people from unreasonable searches and seizures of four specific things-persons, houses, papers, and effects. They identified those four categories as "the objects of privacy protection to which the Constitution would extend, leaving further expansion to the good judgment ... of the people through their representatives in the legislature." Carter, supra, at 97-98, 119 S.Ct. 469 (opinion of Scalia, J.).

This limiting language was important to the founders. Madison's first draft of the Fourth Amendment used a different phrase: "their persons, their houses, their papers, and their other property ." 1 Annals of Cong. 452 (1789) (emphasis added). In one of the few changes made to Madison's draft, the House Committee of Eleven changed "other property" to "effects." See House Committee of Eleven Report (July 28, 1789), in N. Cogan, The Complete Bill of Rights 334 (2d ed. 2015). This change might have narrowed the Fourth Amendment by clarifying that it does not protect real property (other than houses). See Oliver v. United States, 466 U.S. 170, 177, and n. 7, 104 S.Ct. 1735, 80 L.Ed.2d 214 (1984) ; Davies, Recovering the Original Fourth Amendment, 98 Mich. L. Rev. 547, 709-714 (1999) (Davies). Or the change might have broadened the Fourth Amendment by clarifying that it protects commercial goods, not just personal possessions. See Donahue 1301. Or it might have done both. Whatever its ultimate effect, the change reveals that the Founders understood the phrase "persons, houses, papers, and effects" to be an important measure of the Fourth Amendment's overall scope. See Davies 710. The Katz test, however, displaces and renders that phrase entirely "superfluous." Jones, 565 U.S., at 405, 132 S.Ct. 945.

D

"[P]ersons, houses, papers, and effects" are not the only words that the Katz test reads out of the Fourth Amendment. The Fourth Amendment specifies that the people have a right to be secure from unreasonable searches of "their" persons, houses, papers, and effects. Although phrased in the plural, "[t]he obvious meaning of ['their'] is that each person has the right to be secure against unreasonable searches *2242and seizures in his own person, house, papers, and effects." Carter, supra, at 92, 119 S.Ct. 469 (opinion of Scalia, J.); see also District of Columbia v. Heller, 554 U.S. 570, 579, 128 S.Ct. 2783, 171 L.Ed.2d 637 (2008) (explaining that the Constitution uses the plural phrase "the people" to "refer to individual rights, not 'collective' rights"). Stated differently, the word "their" means, at the very least, that individuals do not have Fourth Amendment rights in someone else's property. See Carter, supra, at 92-94, 119 S.Ct. 469 (opinion of Scalia, J.). Yet, under the Katz test, individuals can have a reasonable expectation of privacy in another person's property. See, e.g., Carter, 525 U.S., at 89, 119 S.Ct. 469 (majority opinion) ("[A] person may have a legitimate expectation of privacy in the house of someone else"). Until today, our precedents have not acknowledged that individuals can claim a reasonable expectation of privacy in someone else's business records. See ante, at 2224 (KENNEDY, J., dissenting). But the Court erases that line in this case, at least for cell-site location records. In doing so, it confirms that the Katz test does not necessarily require an individual to prove that the government searched his person, house, paper, or effect.

Carpenter attempts to argue that the cell-site records are, in fact, his "papers," see Brief for Petitioner 32-35; Reply Brief 14-15, but his arguments are unpersuasive, see ante, at 2229 - 2230 (opinion of KENNEDY, J.); post, at 2257 - 2259 (ALITO, J., dissenting). Carpenter stipulated below that the cell-site records are the business records of Sprint and MetroPCS. See App. 51. He cites no property law in his briefs to this Court, and he does not explain how he has a property right in the companies' records under the law of any jurisdiction at any point in American history. If someone stole these records from Sprint or MetroPCS, Carpenter does not argue that he could recover in a traditional tort action. Nor do his contracts with Sprint and MetroPCS make the records his, even though such provisions could exist in the marketplace. Cf., e.g., Google Terms of Service, https://policies.google.com/terms ("Some of our Services allow you to upload, submit, store, send or receive content. You retain ownership of any intellectual property rights that you hold in that content. In short, what belongs to you stays yours").

Instead of property, tort, or contract law, Carpenter relies on the federal Telecommunications Act of 1996 to demonstrate that the cell site records are his papers. The Telecommunications Act generally bars cell-phone companies from disclosing customers' cell site location information to the public. See 47 U.S.C. § 222(c). This is sufficient to make the records his, Carpenter argues, because the Fourth Amendment merely requires him to identify a source of "positive law" that "protects against access by the public without consent." Brief for Petitioner 32-33 (citing Baude & Stern, The Positive Law Model of the Fourth Amendment, 129 Harv. L. Rev. 1821, 1825-1826 (2016) ; emphasis deleted).

Carpenter is mistaken. To come within the text of the Fourth Amendment, Carpenter must prove that the cell-site records are his ; positive law is potentially relevant only insofar as it answers that question. The text of the Fourth Amendment cannot plausibly be read to mean "any violation of positive law" any more than it can plausibly be read to mean "any violation of a reasonable expectation of privacy."

Thus, the Telecommunications Act is insufficient because it does not give Carpenter a property right in the cell-site records. Section 222, titled "Privacy of customer *2243information," protects customers' privacy by preventing cell-phone companies from disclosing sensitive information about them. The statute creates a "duty to protect the confidentiality" of information relating to customers, § 222(a), and creates "[p]rivacy requirements" that limit the disclosure of that information, § 222(c)(1). Nothing in the text pre-empts state property law or gives customers a property interest in the companies' business records (assuming Congress even has that authority).9 Although § 222"protects the interests of individuals against wrongful uses or disclosures of personal data, the rationale for these legal protections has not historically been grounded on a perception that people have property rights in personal data as such." Samuelson, Privacy as Intellectual Property? 52 Stan. L. Rev. 1125, 1130-1131 (2000) (footnote omitted). Any property rights remain with the companies.

E

The Katz test comes closer to the text of the Fourth Amendment when it asks whether an expectation of privacy is "reasonable," but it ultimately distorts that term as well. The Fourth Amendment forbids "unreasonable searches." In other words, reasonableness determines the legality of a search, not "whether a search ... within the meaning of the Constitution has occurred ." Carter, 525 U.S., at 97, 119 S.Ct. 469 (opinion of Scalia, J.) (internal quotation marks omitted).

Moreover, the Katz test invokes the concept of reasonableness in a way that would be foreign to the ratifiers of the Fourth Amendment. Originally, the word "unreasonable" in the Fourth Amendment likely meant "against reason"-as in "against the reason of the common law." See Donahue 1270-1275; Davies 686-693; California v. Acevedo, 500 U.S. 565, 583, 111 S.Ct. 1982, 114 L.Ed.2d 619 (1991) (Scalia, J., concurring in judgment). At the founding, searches and seizures were regulated by a robust body of common-law rules. See generally W. Cuddihy, The Fourth Amendment: Origins and Original Meaning 602-1791 (2009); e.g., Wilson v. Arkansas, 514 U.S. 927, 931-936, 115 S.Ct. 1914, 131 L.Ed.2d 976 (1995) (discussing the common-law knock-and-announce rule). The search-and-seizure practices that the Founders feared most-such as general warrants-were already illegal under the common law, and jurists such as Lord Coke described violations of the common law as "against reason." See Donahue 1270-1271, and n. 513. Locke, Blackstone, Adams, and other influential figures shortened the phrase "against reason" to "unreasonable." See id., at 1270-1275. Thus, by prohibiting "unreasonable" searches and seizures in the Fourth Amendment, the Founders ensured that the newly created Congress could not use legislation to abolish the established common-law rules of search and seizure. See T. Cooley, Constitutional Limitations *303 (2d ed. 1871); 3 J. Story, Commentaries on the *2244Constitution of the United States § 1895, p. 748 (1833).

Although the Court today maintains that its decision is based on "Founding-era understandings," ante, at 2214, the Founders would be puzzled by the Court's conclusion as well as its reasoning. The Court holds that the Government unreasonably searched Carpenter by subpoenaing the cell-site records of Sprint and MetroPCS without a warrant. But the Founders would not recognize the Court's "warrant requirement." Ante, at 2222. The common law required warrants for some types of searches and seizures, but not for many others. The relevant rule depended on context. See Acevedo, supra, at 583-584, 111 S.Ct. 1982 (opinion of Scalia, J.); Amar, Fourth Amendment First Principles, 107 Harv. L. Rev. 757, 763-770 (1994) ; Davies 738-739. In cases like this one, a subpoena for third-party documents was not a "search" to begin with, and the common law did not limit the government's authority to subpoena third parties. See post, at 2247 - 2253 (ALITO, J., dissenting). Suffice it to say, the Founders would be confused by this Court's transformation of their common-law protection of property into a "warrant requirement" and a vague inquiry into "reasonable expectations of privacy."

III

That the Katz test departs so far from the text of the Fourth Amendment is reason enough to reject it. But the Katz test also has proved unworkable in practice. Jurists and commentators tasked with deciphering our jurisprudence have described the Katz regime as "an unpredictable jumble," "a mass of contradictions and obscurities," "all over the map," "riddled with inconsistency and incoherence," "a series of inconsistent and bizarre results that [the Court] has left entirely undefended," "unstable," "chameleon-like," " 'notoriously unhelpful,' " "a conclusion rather than a starting point for analysis," "distressingly unmanageable," "a dismal failure," "flawed to the core," "unadorned fiat," and "inspired by the kind of logic that produced Rube Goldberg's bizarre contraptions."10 Even Justice Harlan, four years after penning his concurrence in Katz, confessed that the test encouraged "the substitution of words for analysis." United States v. White, 401 U.S. 745, 786, 91 S.Ct. 1122, 28 L.Ed.2d 453 (1971) (dissenting opinion).

*2245After 50 years, it is still unclear what question the Katz test is even asking. This Court has steadfastly declined to elaborate the relevant considerations or identify any meaningful constraints. See, e.g., ante, at 2213 - 2214 ("[N]o single rubric definitively resolves which expectations of privacy are entitled to protection"); O'Connor v. Ortega, 480 U.S. 709, 715, 107 S.Ct. 1492, 94 L.Ed.2d 714 (1987) (plurality opinion) ("We have no talisman that determines in all cases those privacy expectations that society is prepared to accept as reasonable"); Oliver, 466 U.S., at 177, 104 S.Ct. 1735 ("No single factor determines whether an individual legitimately may claim under the Fourth Amendment that a place should be free of government intrusion").

Justice Harlan's original formulation of the Katz test appears to ask a descriptive question: Whether a given expectation of privacy is "one that society is prepared to recognize as 'reasonable.' " 389 U.S., at 361, 88 S.Ct. 507. As written, the Katz test turns on society's actual, current views about the reasonableness of various expectations of privacy.

But this descriptive understanding presents several problems. For starters, it is easily circumvented. If, for example, "the Government were suddenly to announce on nationwide television that all homes henceforth would be subject to warrantless entry," individuals could not realistically expect privacy in their homes. Smith, 442 U.S., at 740, n. 5, 99 S.Ct. 2577 ; see also Chemerinsky, Rediscovering Brandeis's Right to Privacy, 45 Brandeis L.J. 643, 650 (2007) ("[Under Katz, t]he government seemingly can deny privacy just by letting people know in advance not to expect any"). A purely descriptive understanding of the Katz test also risks "circular[ity]." Kyllo, 533 U.S., at 34, 121 S.Ct. 2038. While this Court is supposed to base its decisions on society's expectations of privacy, society's expectations of privacy are, in turn, shaped by this Court's decisions. See Posner, The Uncertain Protection of Privacy by the Supreme Court, 1979 S.Ct. Rev. 173, 188 ("[W]hether [a person] will or will not have [a reasonable] expectation [of privacy] will depend on what the legal rule is").

To address this circularity problem, the Court has insisted that expectations of privacy must come from outside its Fourth Amendment precedents, "either by reference to concepts of real or personal property law or to understandings that are recognized and permitted by society." Rakas v. Illinois, 439 U.S. 128, 144, n. 12, 99 S.Ct. 421, 58 L.Ed.2d 387 (1978). But the Court's supposed reliance on "real or personal property law" rings hollow. The whole point of Katz was to " 'discredi[t]' " the relationship between the Fourth Amendment and property law, 389 U.S., at 353, 88 S.Ct. 507, and this Court has repeatedly downplayed the importance of property law under the Katz test, see, e.g., United States v. Salvucci, 448 U.S. 83, 91, 100 S.Ct. 2547, 65 L.Ed.2d 619 (1980) ("[P]roperty rights are neither the beginning nor the end of this Court's inquiry [under Katz ]"); Rawlings v. Kentucky, 448 U.S. 98, 105, 100 S.Ct. 2556, 65 L.Ed.2d 633 (1980) ("[This Court has] emphatically rejected the notion that 'arcane' concepts of property law ought to control the ability to claim the protections of the Fourth Amendment"). Today, for example, the Court makes no mention of property law, except to reject its relevance. See ante, at 2214, and n. 1.

As for "understandings that are recognized or permitted in society," this Court has never answered even the most basic questions about what this means. See Kerr, *2246Four Models of Fourth Amendment Protection, 60 Stan. L. Rev. 503, 504-505 (2007). For example, our precedents do not explain who is included in "society," how we know what they "recogniz[e] or permi[t]," and how much of society must agree before something constitutes an "understanding."

Here, for example, society might prefer a balanced regime that prohibits the Government from obtaining cell-site location information unless it can persuade a neutral magistrate that the information bears on an ongoing criminal investigation. That is precisely the regime Congress created under the Stored Communications Act and Telecommunications Act. See 47 U.S.C. § 222(c)(1) ; 18 U.S.C. §§ 2703(c)(1)(B), (d). With no sense of irony, the Court invalidates this regime today-the one that society actually created "in the form of its elected representatives in Congress." 819 F.3d 880, 890 (2016).

Truth be told, this Court does not treat the Katz test as a descriptive inquiry. Although the Katz test is phrased in descriptive terms about society's views, this Court treats it like a normative question-whether a particular practice should be considered a search under the Fourth Amendment. Justice Harlan thought this was the best way to understand his test. See White, 401 U.S., at 786, 91 S.Ct. 1122 (dissenting opinion) (explaining that courts must assess the "desirability" of privacy expectations and ask whether courts "should" recognize them by "balanc[ing]" the "impact on the individual's sense of security ... against the utility of the conduct as a technique of law enforcement"). And a normative understanding is the only way to make sense of this Court's precedents, which bear the hallmarks of subjective policymaking instead of neutral legal decisionmaking. "[T]he only thing the past three decades have established about the Katz test" is that society's expectations of privacy "bear an uncanny resemblance to those expectations of privacy that this Court considers reasonable." Carter, 525 U.S., at 97, 119 S.Ct. 469 (opinion of Scalia, J.). Yet, "[t]hough we know ourselves to be eminently reasonable, self-awareness of eminent reasonableness is not really a substitute for democratic election." Sosa v. Alvarez-Machain, 542 U.S. 692, 750, 124 S.Ct. 2739, 159 L.Ed.2d 718 (2004) (Scalia, J., concurring in part and concurring in judgment).

* * *

In several recent decisions, this Court has declined to apply the Katz test because it threatened to narrow the original scope of the Fourth Amendment. See Grady v. North Carolina, 575 U.S. ----, ----, 135 S.Ct. 1368, 1370, 191 L.Ed.2d 459 (2015) (per curiam ); Florida v. Jardines, 569 U.S. 1, 5, 133 S.Ct. 1409, 185 L.Ed.2d 495 (2013) ; Jones, 565 U.S., at 406-407, 132 S.Ct. 945. But as today's decision demonstrates, Katz can also be invoked to expand the Fourth Amendment beyond its original scope. This Court should not tolerate errors in either direction. "The People, through ratification, have already weighed the policy tradeoffs that constitutional rights entail." Luis v. United States, 578 U.S. ----, ----, 136 S.Ct. 1083, 1101, 194 L.Ed.2d 256 (2016) (THOMAS, J., concurring in judgment). Whether the rights they ratified are too broad or too narrow by modern lights, this Court has no authority to unilaterally alter the document they approved.

Because the Katz test is a failed experiment, this Court is dutybound to reconsider it. Until it does, I agree with my dissenting colleagues' reading of our precedents. Accordingly, I respectfully dissent.

Justice ALITO, with whom Justice THOMAS joins, dissenting.

I share the Court's concern about the effect of new technology on personal privacy, *2247but I fear that today's decision will do far more harm than good. The Court's reasoning fractures two fundamental pillars of Fourth Amendment law, and in doing so, it guarantees a blizzard of litigation while threatening many legitimate and valuable investigative practices upon which law enforcement has rightfully come to rely.

First, the Court ignores the basic distinction between an actual search (dispatching law enforcement officers to enter private premises and root through private papers and effects) and an order merely requiring a party to look through its own records and produce specified documents. The former, which intrudes on personal privacy far more deeply, requires probable cause; the latter does not. Treating an order to produce like an actual search, as today's decision does, is revolutionary. It violates both the original understanding of the Fourth Amendment and more than a century of Supreme Court precedent. Unless it is somehow restricted to the particular situation in the present case, the Court's move will cause upheaval. Must every grand jury subpoena duces tecum be supported by probable cause? If so, investigations of terrorism, political corruption, white-collar crime, and many other offenses will be stymied. And what about subpoenas and other document-production orders issued by administrative agencies? See, e.g., 15 U.S.C. § 57b-1(c) (Federal Trade Commission); §§ 77s(c), 78u(a)-(b) (Securities and Exchange Commission); 29 U.S.C. § 657(b) (Occupational Safety and Health Administration); 29 C.F.R. § 1601.16(a)(2) (2017) (Equal Employment Opportunity Commission).

Second, the Court allows a defendant to object to the search of a third party's property. This also is revolutionary. The Fourth Amendment protects "[t]he right of the people to be secure in their persons, houses, papers, and effects" (emphasis added), not the persons, houses, papers, and effects of others. Until today, we have been careful to heed this fundamental feature of the Amendment's text. This was true when the Fourth Amendment was tied to property law, and it remained true after Katz v. United States, 389 U.S. 347, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967), broadened the Amendment's reach.

By departing dramatically from these fundamental principles, the Court destabilizes long-established Fourth Amendment doctrine. We will be making repairs-or picking up the pieces-for a long time to come.

I

Today the majority holds that a court order requiring the production of cell-site records may be issued only after the Government demonstrates probable cause. See ante, at 2220 - 2221. That is a serious and consequential mistake. The Court's holding is based on the premise that the order issued in this case was an actual "search" within the meaning of the Fourth Amendment, but that premise is inconsistent with the original meaning of the Fourth Amendment and with more than a century of precedent.

A

The order in this case was the functional equivalent of a subpoena for documents, and there is no evidence that these writs were regarded as "searches" at the time of the founding. Subpoenas duces tecum and other forms of compulsory document production were well known to the founding generation. Blackstone dated the first writ of subpoena to the reign of King Richard II in the late 14th century, and by the end of the 15th century, the use of such writs had "become the daily practice of the [Chancery] court." 3 W. Blackstone, *2248Commentaries on the Laws of England 53 (G. Tucker ed. 1803) (Blackstone). Over the next 200 years, subpoenas would grow in prominence and power in tandem with the Court of Chancery, and by the end of Charles II's reign in 1685, two important innovations had occurred.

First, the Court of Chancery developed a new species of subpoena. Until this point, subpoenas had been used largely to compel attendance and oral testimony from witnesses; these subpoenas correspond to today's subpoenas ad testificandum . But the Court of Chancery also improvised a new version of the writ that tacked onto a regular subpoena an order compelling the witness to bring certain items with him. By issuing these so-called subpoenas duces tecum, the Court of Chancery could compel the production of papers, books, and other forms of physical evidence, whether from the parties to the case or from third parties. Such subpoenas were sufficiently commonplace by 1623 that a leading treatise on the practice of law could refer in passing to the fee for a "Sub poena of Ducas tecum " (seven shillings and two pence) without needing to elaborate further. T. Powell, The Attourneys Academy 79 (1623). Subpoenas duces tecum would swell in use over the next century as the rules for their application became ever more developed and definite. See, e.g., 1 G. Jacob, The Compleat Chancery-Practiser 290 (1730) ("The Subpoena duces tecum is awarded when the Defendant has confessed by his Answer that he hath such Writings in his Hands as are prayed by the Bill to be discovered or brought into Court").

Second, although this new species of subpoena had its origins in the Court of Chancery, it soon made an appearance in the work of the common-law courts as well. One court later reported that "[t]he Courts of Common law ... employed the same or similar means ... from the time of Charles the Second at least." Amey v. Long, 9 East. 473, 484, 103 Eng. Rep. 653, 658 (K.B. 1808).

By the time Blackstone published his Commentaries on the Laws of England in the 1760's, the use of subpoenas duces tecum had bled over substantially from the courts of equity to the common-law courts. Admittedly, the transition was still incomplete: In the context of jury trials, for example, Blackstone complained about "the want of a compulsive power for the production of books and papers belonging to the parties." Blackstone 381; see also, e.g., Entick v. Carrington, 19 State Trials 1029, 1073 (K.B. 1765) ("I wish some cases had been shewn, where the law forceth evidence out of the owner's custody by process. [But] where the adversary has by force or fraud got possession of your own proper evidence, there is no way to get it back but by action"). But Blackstone found some comfort in the fact that at least those documents "[i]n the hands of third persons ... can generally be obtained by rule of court, or by adding a clause of requisition to the writ of subpoena, which is then called a subpoena duces tecum ." Blackstone 381; see also, e.g., Leeds v. Cook, 4 Esp. 256, 257, 170 Eng. Rep. 711 (N.P. 1803) (third-party subpoena duces tecum ); Rex v. Babb, 3 T.R. 579, 580, 100 Eng. Rep. 743, 744 (K.B. 1790) (third-party document production). One of the primary questions outstanding, then, was whether common-law courts would remedy the "defect[s]" identified by the Commentaries, and allow parties to use subpoenas duces tecum not only with respect to third parties but also with respect to each other. Blackstone 381.

That question soon found an affirmative answer on both sides of the Atlantic. In the United States, the First Congress established the federal court system in the *2249Judiciary Act of 1789. As part of that Act, Congress authorized "all the said courts of the United States ... in the trial of actions at law, on motion and due notice thereof being given, to require the parties to produce books or writings in their possession or power, which contain evidence pertinent to the issue, in cases and under circumstances where they might be compelled to produce the same by the ordinary rules of proceeding in chancery." § 15, 1 Stat. 82. From that point forward, federal courts in the United States could compel the production of documents regardless of whether those documents were held by parties to the case or by third parties.

In Great Britain, too, it was soon definitively established that common-law courts, like their counterparts in equity, could subpoena documents held either by parties to the case or by third parties. After proceeding in fits and starts, the King's Bench eventually held in Amey v. Long that the "writ of subpoena duces tecum [is] a writ of compulsory obligation and effect in the law." 9 East., at 486, 103 Eng. Rep., at 658. Writing for a unanimous court, Lord Chief Justice Ellenborough explained that "[t]he right to resort to means competent to compel the production of written, as well as oral, testimony seems essential to the very existence and constitution of a Court of Common Law." Id., at 484, 103 Eng. Rep., at 658. Without the power to issue subpoenas duces tecum, the Lord Chief Justice observed, common-law courts "could not possibly proceed with due effect." Ibid.

The prevalence of subpoenas duces tecum at the time of the founding was not limited to the civil context. In criminal cases, courts and prosecutors were also using the writ to compel the production of necessary documents. In Rex v. Dixon, 3 Burr. 1687, 97 Eng. Rep. 1047 (K.B. 1765), for example, the King's Bench considered the propriety of a subpoena duces tecum served on an attorney named Samuel Dixon. Dixon had been called "to give evidence before the grand jury of the county of Northampton" and specifically "to produce three vouchers ... in order to found a prosecution by way of indictment against [his client] Peach ... for forgery." Id., at 1687, 97 Eng. Rep., at 1047-1048. Although the court ultimately held that Dixon had not needed to produce the vouchers on account of attorney-client privilege, none of the justices expressed the slightest doubt about the general propriety of subpoenas duces tecum in the criminal context. See id., at 1688, 97 Eng. Rep., at 1048. As Lord Chief Justice Ellenborough later explained, "[i]n that case no objection was taken to the writ, but to the special circumstances under which the party possessed the papers; so that the Court may be considered as recognizing the general obligation to obey writs of that description in other cases." Amey, supra, at 485, 103 Eng. Rep., at 658; see also 4 J. Chitty, Practical Treatise on the Criminal Law 185 (1816) (template for criminal subpoena duces tecum ).

As Dixon shows, subpoenas duces tecum were routine in part because of their close association with grand juries. Early American colonists imported the grand jury, like so many other common-law traditions, and they quickly flourished. See United States v. Calandra, 414 U.S. 338, 342-343, 94 S.Ct. 613, 38 L.Ed.2d 561 (1974). Grand juries were empaneled by the federal courts almost as soon as the latter were established, and both they and their state counterparts actively exercised their wide-ranging common-law authority. See R. Younger, The People's Panel 47-55 (1963). Indeed, "the Founders thought the grand jury so essential ... that they provided in the Fifth Amendment that federal prosecution for serious crimes can only be instituted by 'a presentment or *2250indictment of a Grand Jury.' " Calandra, supra, at 343, 94 S.Ct. 613.

Given the popularity and prevalence of grand juries at the time, the Founders must have been intimately familiar with the tools they used-including compulsory process-to accomplish their work. As a matter of tradition, grand juries were "accorded wide latitude to inquire into violations of criminal law," including the power to "compel the production of evidence or the testimony of witnesses as [they] conside[r] appropriate." Ibid. Long before national independence was achieved, grand juries were already using their broad inquisitorial powers not only to present and indict criminal suspects but also to inspect public buildings, to levy taxes, to supervise the administration of the laws, to advance municipal reforms such as street repair and bridge maintenance, and in some cases even to propose legislation. Younger, supra, at 5-26. Of course, such work depended entirely on grand juries' ability to access any relevant documents.

Grand juries continued to exercise these broad inquisitorial powers up through the time of the founding. See Blair v. United States, 250 U.S. 273, 280, 39 S.Ct. 468, 63 L.Ed. 979 (1919) ("At the foundation of our Federal Government the inquisitorial function of the grand jury and the compulsion of witnesses were recognized as incidents of the judicial power"). In a series of lectures delivered in the early 1790's, Justice James Wilson crowed that grand juries were "the peculiar boast of the common law" thanks in part to their wide-ranging authority: "All the operations of government, and of its ministers and officers, are within the compass of their view and research." 2 J. Wilson, The Works of James Wilson 534, 537 (R. McCloskey ed. 1967). That reflected the broader insight that "[t]he grand jury's investigative power must be broad if its public responsibility is adequately to be discharged." Calandra, supra, at 344, 94 S.Ct. 613.

Compulsory process was also familiar to the founding generation in part because it reflected "the ancient proposition of law" that " ' "the public ... has a right to every man's evidence." ' " United States v. Nixon, 418 U.S. 683, 709, 94 S.Ct. 3090, 41 L.Ed.2d 1039 (1974) ; see also ante, at 2228 (KENNEDY, J., dissenting). As early as 1612, "Lord Bacon is reported to have declared that 'all subjects, without distinction of degrees, owe to the King tribute and service, not only of their deed and hand, but of their knowledge and discovery.' " Blair, supra, at 279-280, 39 S.Ct. 468. That duty could be "onerous at times," yet the Founders considered it "necessary to the administration of justice according to the forms and modes established in our system of government." Id., at 281, 39 S.Ct. 468 ; see also Calandra, supra, at 345, 94 S.Ct. 613.

B

Talk of kings and common-law writs may seem out of place in a case about cell-site records and the protections afforded by the Fourth Amendment in the modern age. But this history matters, not least because it tells us what was on the minds of those who ratified the Fourth Amendment and how they understood its scope. That history makes it abundantly clear that the Fourth Amendment, as originally understood, did not apply to the compulsory production of documents at all.

The Fourth Amendment does not regulate all methods by which the Government obtains documents. Rather, it prohibits only those "searches and seizures" of "persons, houses, papers, and effects" that are "unreasonable." Consistent with that language, "at least until the latter half of the 20th century" "our Fourth Amendment jurisprudence was tied to common-law trespass."

*2251United States v. Jones, 565 U.S. 400, 405, 132 S.Ct. 945, 181 L.Ed.2d 911 (2012). So by its terms, the Fourth Amendment does not apply to the compulsory production of documents, a practice that involves neither any physical intrusion into private space nor any taking of property by agents of the state. Even Justice Brandeis-a stalwart proponent of construing the Fourth Amendment liberally-acknowledged that "under any ordinary construction of language," "there is no 'search' or 'seizure' when a defendant is required to produce a document in the orderly process of a court's procedure." Olmstead v. United States, 277 U.S. 438, 476, 48 S.Ct. 564, 72 L.Ed. 944 (1928) (dissenting opinion).1

Nor is there any reason to believe that the Founders intended the Fourth Amendment to regulate courts' use of compulsory process. American colonists rebelled against the Crown's physical invasions of their persons and their property, not against its acquisition of information by any and all means. As Justice Black once put it, "[t]he Fourth Amendment was aimed directly at the abhorred practice of breaking in, ransacking and searching homes and other buildings and seizing people's personal belongings without warrants issued by magistrates." Katz, 389 U.S., at 367, 88 S.Ct. 507 (dissenting opinion). More recently, we have acknowledged that "the Fourth Amendment was the founding generation's response to the reviled 'general warrants' and 'writs of assistance' of the colonial era, which allowed British officers to rummage through homes in an unrestrained search for evidence of criminal activity." Riley v. California, 573 U.S. ----, ----, 134 S.Ct. 2473, 2494, 189 L.Ed.2d 430 (2014).

General warrants and writs of assistance were noxious not because they allowed the Government to acquire evidence in criminal investigations, but because of the means by which they permitted the Government to acquire that evidence. Then, as today, searches could be quite invasive. Searches generally begin with officers "mak[ing] nonconsensual entries into areas not open to the public." Donovan v. Lone Steer, Inc., 464 U.S. 408, 414, 104 S.Ct. 769, 78 L.Ed.2d 567 (1984). Once there, officers are necessarily in a position to observe private spaces generally shielded from the public and discernible only with the owner's consent. Private area after private area becomes exposed to the officers' eyes as they rummage through the owner's property in their hunt for the object or objects of the search. If they are searching for documents, officers may additionally have to rifle through many other papers-potentially filled with the most intimate details of a person's thoughts and life-before they find the specific information *2252they are seeking. See Andresen v. Maryland, 427 U.S. 463, 482, n. 11, 96 S.Ct. 2737, 49 L.Ed.2d 627 (1976). If anything sufficiently incriminating comes into view, officers seize it. Horton v. California, 496 U.S. 128, 136-137, 110 S.Ct. 2301, 110 L.Ed.2d 112 (1990). Physical destruction always lurks as an underlying possibility; "officers executing search warrants on occasion must damage property in order to perform their duty." Dalia v. United States, 441 U.S. 238, 258, 99 S.Ct. 1682, 60 L.Ed.2d 177 (1979) ; see, e.g., United States v. Ramirez, 523 U.S. 65, 71-72, 118 S.Ct. 992, 140 L.Ed.2d 191 (1998) (breaking garage window); United States v. Ross, 456 U.S. 798, 817-818, 102 S.Ct. 2157, 72 L.Ed.2d 572 (1982) (ripping open car upholstery); Brown v. Battle Creek Police Dept., 844 F.3d 556, 572 (C.A.6 2016) (shooting and killing two pet dogs); Lawmaster v. Ward, 125 F.3d 1341, 1350, n. 3 (C.A.10 1997) (breaking locks).

Compliance with a subpoena duces tecum requires none of that. A subpoena duces tecum permits a subpoenaed individual to conduct the search for the relevant documents himself, without law enforcement officers entering his home or rooting through his papers and effects. As a result, subpoenas avoid the many incidental invasions of privacy that necessarily accompany any actual search. And it was those invasions of privacy-which, although incidental, could often be extremely intrusive and damaging-that led to the adoption of the Fourth Amendment.

Neither this Court nor any of the parties have offered the slightest bit of historical evidence to support the idea that the Fourth Amendment originally applied to subpoenas duces tecum and other forms of compulsory process. That is telling, for as I have explained, these forms of compulsory process were a feature of criminal (and civil) procedure well known to the Founders. The Founders would thus have understood that holding the compulsory production of documents to the same standard as actual searches and seizures would cripple the work of courts in civil and criminal cases alike. It would be remarkable to think that, despite that knowledge, the Founders would have gone ahead and sought to impose such a requirement. It would be even more incredible to believe that the Founders would have imposed that requirement through the inapt vehicle of an amendment directed at different concerns. But it would blink reality entirely to argue that this entire process happened without anyone saying the least thing about it -not during the drafting of the Bill of Rights, not during any of the subsequent ratification debates, and not for most of the century that followed. If the Founders thought the Fourth Amendment applied to the compulsory production of documents, one would imagine that there would be some founding-era evidence of the Fourth Amendment being applied to the compulsory production of documents. Cf. Free Enterprise Fund v. Public Company Accounting Oversight Bd., 561 U.S. 477, 505, 130 S.Ct. 3138, 177 L.Ed.2d 706 (2010) ; Printz v. United States, 521 U.S. 898, 905, 117 S.Ct. 2365, 138 L.Ed.2d 914 (1997). Yet none has been brought to our attention.

C

Of course, our jurisprudence has not stood still since 1791. We now evaluate subpoenas duces tecum and other forms of compulsory document production under the Fourth Amendment, although we employ a reasonableness standard that is less demanding than the requirements for a warrant. But the road to that doctrinal destination was anything but smooth, and our initial missteps-and the subsequent struggle to extricate ourselves from their consequences-should provide an object *2253lesson for today's majority about the dangers of holding compulsory process to the same standard as actual searches and seizures.

For almost a century after the Fourth Amendment was enacted, this Court said and did nothing to indicate that it might regulate the compulsory production of documents. But that changed temporarily when the Court decided Boyd v. United States, 116 U.S. 616, 6 S.Ct. 524, 29 L.Ed. 746 (1886), the first-and, until today, the only-case in which this Court has ever held the compulsory production of documents to the same standard as actual searches and seizures.

The Boyd Court held that a court order compelling a company to produce potentially incriminating business records violated both the Fourth and the Fifth Amendments. The Court acknowledged that "certain aggravating incidents of actual search and seizure, such as forcible entry into a man's house and searching amongst his papers, are wanting" when the Government relies on compulsory process. Id., at 622, 6 S.Ct. 524. But it nevertheless asserted that the Fourth Amendment ought to "be liberally construed," id., at 635, 6 S.Ct. 524, and further reasoned that compulsory process "effects the sole object and purpose of search and seizure" by "forcing from a party evidence against himself," id., at 622, 6 S.Ct. 524. "In this regard," the Court concluded, "the Fourth and Fifth Amendments run almost into each other." Id., at 630, 6 S.Ct. 524. Having equated compulsory process with actual searches and seizures and having melded the Fourth Amendment with the Fifth, the Court then found the order at issue unconstitutional because it compelled the production of property to which the Government did not have superior title. See id., at 622-630, 6 S.Ct. 524.

In a concurrence joined by Chief Justice Waite, Justice Miller agreed that the order violated the Fifth Amendment, id., at 639, 6 S.Ct. 524, but he strongly protested the majority's invocation of the Fourth Amendment. He explained: "[T]here is no reason why this court should assume that the action of the court below, in requiring a party to produce certain papers ..., authorizes an unreasonable search or seizure of the house, papers, or effects of that party. There is in fact no search and no seizure." Ibid. "If the mere service of a notice to produce a paper ... is a search," Justice Miller concluded, "then a change has taken place in the meaning of words, which has not come within my reading, and which I think was unknown at the time the Constitution was made." Id., at 641, 6 S.Ct. 524.

Although Boyd was replete with stirring rhetoric, its reasoning was confused from start to finish in a way that ultimately made the decision unworkable. See 3 W. LaFave, J. Israel, N. King, & O. Kerr, Criminal Procedure § 8.7(a) (4th ed. 2015). Over the next 50 years, the Court would gradually roll back Boyd 's erroneous conflation of compulsory process with actual searches and seizures.

That effort took its first significant stride in Hale v. Henkel, 201 U.S. 43, 26 S.Ct. 370, 50 L.Ed. 652 (1906), where the Court found it "quite clear" and "conclusive" that "the search and seizure clause of the Fourth Amendment was not intended to interfere with the power of courts to compel, through a subpoena duces tecum, the production, upon a trial in court, of documentary evidence." Id., at 73, 26 S.Ct. 370. Without that writ, the Court recognized, "it would be 'utterly impossible to carry on the administration of justice.' " Ibid.

Hale, however, did not entirely liberate subpoenas duces tecum from Fourth *2254Amendment constraints. While refusing to treat such subpoenas as the equivalent of actual searches, Hale concluded that they must not be unreasonable. And it held that the subpoena duces tecum at issue was "far too sweeping in its terms to be regarded as reasonable." Id., at 76, 26 S.Ct. 370. The Hale Court thus left two critical questions unanswered: Under the Fourth Amendment, what makes the compulsory production of documents "reasonable," and how does that standard differ from the one that governs actual searches and seizures?

The Court answered both of those questions definitively in Oklahoma Press Publishing Co. v. Walling, 327 U.S. 186, 66 S.Ct. 494, 90 L.Ed. 614 (1946), where we held that the Fourth Amendment regulates the compelled production of documents, but less stringently than it does full-blown searches and seizures. Oklahoma Press began by admitting that the Court's opinions on the subject had "perhaps too often ... been generative of heat rather than light," "mov[ing] with variant direction" and sometimes having "highly contrasting" "emphasis and tone." Id., at 202, 66 S.Ct. 494. "The primary source of misconception concerning the Fourth Amendment's function" in this context, the Court explained, "lies perhaps in the identification of cases involving so-called 'figurative' or 'constructive' search with cases of actual search and seizure." Ibid. But the Court held that "the basic distinction" between the compulsory production of documents on the one hand, and actual searches and seizures on the other, meant that two different standards had to be applied. Id., at 204, 66 S.Ct. 494.

Having reversed Boyd 's conflation of the compelled production of documents with actual searches and seizures, the Court then set forth the relevant Fourth Amendment standard for the former. When it comes to "the production of corporate or other business records," the Court held that the Fourth Amendment "at the most guards against abuse only by way of too much indefiniteness or breadth in the things required to be 'particularly described,' if also the inquiry is one the demanding agency is authorized by law to make and the materials specified are relevant." Oklahoma Press, supra, at 208, 66 S.Ct. 494. Notably, the Court held that a showing of probable cause was not necessary so long as "the investigation is authorized by Congress, is for a purpose Congress can order, and the documents sought are relevant to the inquiry." Id., at 209, 66 S.Ct. 494.

Since Oklahoma Press, we have consistently hewed to that standard. See, e.g., Lone Steer, Inc., 464 U.S., at 414-415, 104 S.Ct. 769 ; United States v. Miller, 425 U.S. 435, 445-446, 96 S.Ct. 1619, 48 L.Ed.2d 71 (1976) ; California Bankers Assn. v. Shultz, 416 U.S. 21, 67, 94 S.Ct. 1494, 39 L.Ed.2d 812 (1974) ; United States v. Dionisio, 410 U.S. 1, 11-12, 93 S.Ct. 764, 35 L.Ed.2d 67 (1973) ; See v. Seattle, 387 U.S. 541, 544, 87 S.Ct. 1737, 18 L.Ed.2d 943 (1967) ; United States v. Powell, 379 U.S. 48, 57-58, 85 S.Ct. 248, 13 L.Ed.2d 112 (1964) ; McPhaul v. United States, 364 U.S. 372, 382-383, 81 S.Ct. 138, 5 L.Ed.2d 136 (1960) ; United States v. Morton Salt Co., 338 U.S. 632, 652-653, 70 S.Ct. 357, 94 L.Ed. 401 (1950) ; cf. McLane Co. v. EEOC, 581 U.S. ----, ----, 137 S.Ct. 1159, 1169-1170, 197 L.Ed.2d 500 (2017). By applying Oklahoma Press and thereby respecting "the traditional distinction between a search warrant and a subpoena," Miller, supra, at 446, 96 S.Ct. 1619, this Court has reinforced "the basic compromise" between "the public interest" in every man's evidence and the private interest "of men to be free from officious meddling." Oklahoma Press, supra, at 213, 66 S.Ct. 494.

*2255D

Today, however, the majority inexplicably ignores the settled rule of Oklahoma Press in favor of a resurrected version of Boyd . That is mystifying. This should have been an easy case regardless of whether the Court looked to the original understanding of the Fourth Amendment or to our modern doctrine.

As a matter of original understanding, the Fourth Amendment does not regulate the compelled production of documents at all. Here the Government received the relevant cell-site records pursuant to a court order compelling Carpenter's cell service provider to turn them over. That process is thus immune from challenge under the original understanding of the Fourth Amendment.

As a matter of modern doctrine, this case is equally straightforward. As Justice KENNEDY explains, no search or seizure of Carpenter or his property occurred in this case. Ante, at 2226 - 2235; see also Part II, infra . But even if the majority were right that the Government "searched" Carpenter, it would at most be a "figurative or constructive search" governed by the Oklahoma Press standard, not an "actual search" controlled by the Fourth Amendment's warrant requirement.

And there is no doubt that the Government met the Oklahoma Press standard here. Under Oklahoma Press, a court order must " 'be sufficiently limited in scope, relevant in purpose, and specific in directive so that compliance will not be unreasonably burdensome.' " Lone Steer, Inc., supra, at 415, 104 S.Ct. 769. Here, the type of order obtained by the Government almost necessarily satisfies that standard. The Stored Communications Act allows a court to issue the relevant type of order "only if the governmental entity offers specific and articulable facts showing that there are reasonable grounds to believe that ... the records ... sough[t] are relevant and material to an ongoing criminal investigation." 18 U.S.C. § 2703(d). And the court "may quash or modify such order" if the provider objects that the "records requested are unusually voluminous in nature or compliance with such order otherwise would cause an undue burden on such provider." Ibid. No such objection was made in this case, and Carpenter does not suggest that the orders contravened the Oklahoma Press standard in any other way.

That is what makes the majority's opinion so puzzling. It decides that a "search" of Carpenter occurred within the meaning of the Fourth Amendment, but then it leaps straight to imposing requirements that-until this point-have governed only actual searches and seizures. See ante, at 2220 - 2221. Lost in its race to the finish is any real recognition of the century's worth of precedent it jeopardizes. For the majority, this case is apparently no different from one in which Government agents raided Carpenter's home and removed records associated with his cell phone.

Against centuries of precedent and practice, all that the Court can muster is the observation that "this Court has never held that the Government may subpoena third parties for records in which the suspect has a reasonable expectation of privacy." Ante, at 2221. Frankly, I cannot imagine a concession more damning to the Court's argument than that. As the Court well knows, the reason that we have never seen such a case is because-until today-defendants categorically had no "reasonable expectation of privacy" and no property interest in records belonging to third parties. See Part II, infra . By implying otherwise, the Court tries the nice trick of seeking shelter under the cover of precedents that it simultaneously perforates.

*2256Not only that, but even if the Fourth Amendment permitted someone to object to the subpoena of a third party's records, the Court cannot explain why that individual should be entitled to greater Fourth Amendment protection than the party actually being subpoenaed. When parties are subpoenaed to turn over their records, after all, they will at most receive the protection afforded by Oklahoma Press even though they will own and have a reasonable expectation of privacy in the records at issue. Under the Court's decision, however, the Fourth Amendment will extend greater protections to someone else who is not being subpoenaed and does not own the records. That outcome makes no sense, and the Court does not even attempt to defend it.

We have set forth the relevant Fourth Amendment standard for subpoenaing business records many times over. Out of those dozens of cases, the majority cannot find even one that so much as suggests an exception to the Oklahoma Press standard for sufficiently personal information. Instead, we have always "described the constitutional requirements" for compulsory process as being " 'settled' " and as applying categorically to all " 'subpoenas [of] corporate books or records.' " Lone Steer, Inc., 464 U.S., at 415, 104 S.Ct. 769 (internal quotation marks omitted). That standard, we have held, is "the most " protection the Fourth Amendment gives "to the production of corporate records and papers." Oklahoma Press, 327 U.S., at 208, 66 S.Ct. 494 (emphasis added).2

Although the majority announces its holding in the context of the Stored Communications Act, nothing stops its logic from sweeping much further. The Court has offered no meaningful limiting principle, and none is apparent. Cf. Tr. of Oral Arg. 31 (Carpenter's counsel admitting that "a grand jury subpoena ... would be held to the same standard as any other subpoena or subpoena-like request for [cell-site] records").

Holding that subpoenas must meet the same standard as conventional searches will seriously damage, if not destroy, their utility. Even more so than at the founding, today the Government regularly uses subpoenas duces tecum and other forms of compulsory process to carry out its essential functions. See, e.g., Dionisio, 410 U.S., at 11-12, 93 S.Ct. 764 (grand jury subpoenas); McPhaul, 364 U.S., at 382-383, 81 S.Ct. 138 (legislative subpoenas); Oklahoma Press, supra, at 208-209, 66 S.Ct. 494 (administrative subpoenas). Grand juries, for example, have long "compel[led] the production of evidence" in order to determine "whether there is probable cause to believe a crime has been committed." Calandra, 414 U.S., at 343, 94 S.Ct. 613 (emphasis added). Almost by definition, then, grand juries will be unable at first to demonstrate "the probable cause required for a warrant." Ante, at 2221 (majority opinion); see also Oklahoma Press, supra, at 213, 66 S.Ct. 494. If they are required to do so, the effects are as predictable as they are alarming: Many investigations will sputter out at the start, and a host of criminals will be able to evade law enforcement's reach.

"To ensure that justice is done, it is imperative to the function of courts that compulsory process be available for the production of evidence." Nixon, 418 U.S., at 709, 94 S.Ct. 3090. For over a hundred years, we have understood that holding *2257subpoenas to the same standard as actual searches and seizures "would stop much if not all of investigation in the public interest at the threshold of inquiry." Oklahoma Press, supra, at 213, 66 S.Ct. 494. Today a skeptical majority decides to put that understanding to the test.

II

Compounding its initial error, the Court also holds that a defendant has the right under the Fourth Amendment to object to the search of a third party's property. This holding flouts the clear text of the Fourth Amendment, and it cannot be defended under either a property-based interpretation of that Amendment or our decisions applying the reasonable-expectations-of-privacy test adopted in Katz, 389 U.S. 347, 88 S.Ct. 507, 19 L.Ed.2d 576. By allowing Carpenter to object to the search of a third party's property, the Court threatens to revolutionize a second and independent line of Fourth Amendment doctrine.

A

It bears repeating that the Fourth Amendment guarantees "[t]he right of the people to be secure in their persons, houses, papers, and effects." (Emphasis added.) The Fourth Amendment does not confer rights with respect to the persons, houses, papers, and effects of others. Its language makes clear that "Fourth Amendment rights are personal," Rakas v. Illinois, 439 U.S. 128, 140, 99 S.Ct. 421, 58 L.Ed.2d 387 (1978), and as a result, this Court has long insisted that they "may not be asserted vicariously," id., at 133, 99 S.Ct. 421. It follows that a "person who is aggrieved ... only through the introduction of damaging evidence secured by a search of a third person's premises or property has not had any of his Fourth Amendment rights infringed." Id., at 134, 99 S.Ct. 421.

In this case, as Justice KENNEDY cogently explains, the cell-site records obtained by the Government belong to Carpenter's cell service providers, not to Carpenter. See ante, at 2229 - 2230. Carpenter did not create the cell-site records. Nor did he have possession of them; at all relevant times, they were kept by the providers. Once Carpenter subscribed to his provider's service, he had no right to prevent the company from creating or keeping the information in its records. Carpenter also had no right to demand that the providers destroy the records, no right to prevent the providers from destroying the records, and, indeed, no right to modify the records in any way whatsoever (or to prevent the providers from modifying the records). Carpenter, in short, has no meaningful control over the cell-site records, which are created, maintained, altered, used, and eventually destroyed by his cell service providers.

Carpenter responds by pointing to a provision of the Telecommunications Act that requires a provider to disclose cell-site records when a customer so requests. See 47 U.S.C. § 222(c)(2). But a statutory disclosure requirement is hardly sufficient to give someone an ownership interest in the documents that must be copied and disclosed. Many statutes confer a right to obtain copies of documents without creating any property right.3

*2258Carpenter's argument is particularly hard to swallow because nothing in the Telecommunications Act precludes cell service providers from charging customers a fee for accessing cell-site records. See ante, at 2229 - 2230 (KENNEDY, J., dissenting). It would be very strange if the owner of records were required to pay in order to inspect his own property.

Nor does the Telecommunications Act give Carpenter a property right in the cell-site records simply because they are subject to confidentiality restrictions. See 47 U.S.C. § 222(c)(1) (without a customer's permission, a cell service provider may generally "use, disclose, or permit access to individually identifiable [cell-site records]" only with respect to "its provision" of telecommunications services). Many federal statutes impose similar restrictions on private entities' use or dissemination of information in their own records without conferring a property right on third parties.4

*2259It would be especially strange to hold that the Telecommunication Act's confidentiality provision confers a property right when the Act creates an express exception for any disclosure of records that is "required by law." 47 U.S.C. § 222(c)(1). So not only does Carpenter lack " 'the most essential and beneficial' " of the " 'constituent elements' " of property, Dickman v. Commissioner, 465 U.S. 330, 336, 104 S.Ct. 1086, 79 L.Ed.2d 343 (1984) -i.e., the right to use the property to the exclusion of others-but he cannot even exclude the party he would most like to keep out, namely, the Government.5

For all these reasons, there is no plausible ground for maintaining that the information at issue here represents Carpenter's "papers" or "effects."6

B

In the days when this Court followed an exclusively property-based approach to the Fourth Amendment, the distinction between an individual's Fourth Amendment rights and those of a third party was clear cut. We first asked whether the object of the search-say, a house, papers, or effects-belonged to the defendant, and, if it did, whether the Government had committed a "trespass" in acquiring the evidence at issue. Jones, 565 U.S., at 411, n. 8, 132 S.Ct. 945.

When the Court held in Katz that "property rights are not the sole measure of Fourth Amendment violations," Soldal v. Cook County, 506 U.S. 56, 64, 113 S.Ct. 538, 121 L.Ed.2d 450 (1992), the sharp boundary between personal and third-party rights was tested. Under Katz, a party may invoke the Fourth Amendment whenever law enforcement officers violate the party's "justifiable" or "reasonable" expectation of privacy. See 389 U.S., at 353, 88 S.Ct. 507 ; see also id., at 361, 88 S.Ct. 507 (Harlan, J., concurring) (applying the Fourth Amendment where "a person [has] exhibited an actual (subjective) expectation of privacy" and where that "expectation [is] one that society is prepared to recognize as 'reasonable' "). Thus freed from *2260the limitations imposed by property law, parties began to argue that they had a reasonable expectation of privacy in items owned by others. After all, if a trusted third party took care not to disclose information about the person in question, that person might well have a reasonable expectation that the information would not be revealed.

Efforts to claim Fourth Amendment protection against searches of the papers and effects of others came to a head in Miller, 425 U.S. 435, 96 S.Ct. 1619, 48 L.Ed.2d 71, where the defendant sought the suppression of two banks' microfilm copies of his checks, deposit slips, and other records. The defendant did not claim that he owned these documents, but he nonetheless argued that "analysis of ownership, property rights and possessory interests in the determination of Fourth Amendment rights ha[d] been severely impeached" by Katz and other recent cases. See Brief for Respondent in United States v. Miller, O.T.1975, No. 74-1179, p. 6. Turning to Katz, he then argued that he had a reasonable expectation of privacy in the banks' records regarding his accounts. Brief for Respondent in No. 74-1179, at 6; see also Miller, supra, at 442-443, 96 S.Ct. 1619.

Acceptance of this argument would have flown in the face of the Fourth Amendment's text, and the Court rejected that development. Because Miller gave up "dominion and control" of the relevant information to his bank, Rakas, 439 U.S., at 149, 99 S.Ct. 421, the Court ruled that he lost any protected Fourth Amendment interest in that information. See Miller, supra, at 442-443, 96 S.Ct. 1619. Later, in Smith v. Maryland, 442 U.S. 735, 745, 99 S.Ct. 2577, 61 L.Ed.2d 220 (1979), the Court reached a similar conclusion regarding a telephone company's records of a customer's calls. As Justice KENNEDY concludes, Miller and Smith are thus best understood as placing "necessary limits on the ability of individuals to assert Fourth Amendment interests in property to which they lack a 'requisite connection.' " Ante, at 2227.

The same is true here, where Carpenter indisputably lacks any meaningful property-based connection to the cell-site records owned by his provider. Because the records are not Carpenter's in any sense, Carpenter may not seek to use the Fourth Amendment to exclude them.

By holding otherwise, the Court effectively allows Carpenter to object to the "search" of a third party's property, not recognizing the revolutionary nature of this change. The Court seems to think that Miller and Smith invented a new "doctrine"-"the third-party doctrine"-and the Court refuses to "extend" this product of the 1970's to a new age of digital communications. Ante, at 2216 - 2217, 2220. But the Court fundamentally misunderstands the role of Miller and Smith . Those decisions did not forge a new doctrine; instead, they rejected an argument that would have disregarded the clear text of the Fourth Amendment and a formidable body of precedent.

In the end, the Court never explains how its decision can be squared with the fact that the Fourth Amendment protects only "[t]he right of the people to be secure in their persons, houses, papers, and effects." (Emphasis added.)

* * *

Although the majority professes a desire not to " 'embarrass the future,' " ante, at 2220, we can guess where today's decision will lead.

One possibility is that the broad principles that the Court seems to embrace will be applied across the board. All subpoenas duces tecum and all other orders compelling *2261the production of documents will require a demonstration of probable cause, and individuals will be able to claim a protected Fourth Amendment interest in any sensitive personal information about them that is collected and owned by third parties. Those would be revolutionary developments indeed.

The other possibility is that this Court will face the embarrassment of explaining in case after case that the principles on which today's decision rests are subject to all sorts of qualifications and limitations that have not yet been discovered. If we take this latter course, we will inevitably end up "mak[ing] a crazy quilt of the Fourth Amendment." Smith, supra, at 745, 99 S.Ct. 2577.

All of this is unnecessary. In the Stored Communications Act, Congress addressed the specific problem at issue in this case. The Act restricts the misuse of cell-site records by cell service providers, something that the Fourth Amendment cannot do. The Act also goes beyond current Fourth Amendment case law in restricting access by law enforcement. It permits law enforcement officers to acquire cell-site records only if they meet a heightened standard and obtain a court order. If the American people now think that the Act is inadequate or needs updating, they can turn to their elected representatives to adopt more protective provisions. Because the collection and storage of cell-site records affects nearly every American, it is unlikely that the question whether the current law requires strengthening will escape Congress's notice.

Legislation is much preferable to the development of an entirely new body of Fourth Amendment caselaw for many reasons, including the enormous complexity of the subject, the need to respond to rapidly changing technology, and the Fourth Amendment's limited scope. The Fourth Amendment restricts the conduct of the Federal Government and the States; it does not apply to private actors. But today, some of the greatest threats to individual privacy may come from powerful private companies that collect and sometimes misuse vast quantities of data about the lives of ordinary Americans. If today's decision encourages the public to think that this Court can protect them from this looming threat to their privacy, the decision will mislead as well as disrupt. And if holding a provision of the Stored Communications Act to be unconstitutional dissuades Congress from further legislation in this field, the goal of protecting privacy will be greatly disserved.

The desire to make a statement about privacy in the digital age does not justify the consequences that today's decision is likely to produce.

Justice GORSUCH, dissenting.

In the late 1960s this Court suggested for the first time that a search triggering the Fourth Amendment occurs when the government violates an "expectation of privacy" that "society is prepared to recognize as 'reasonable.' " Katz v. United States, 389 U.S. 347, 361, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967) (Harlan, J., concurring). Then, in a pair of decisions in the 1970s applying the Katz test, the Court held that a "reasonable expectation of privacy" doesn't attach to information shared with "third parties." See Smith v. Maryland, 442 U.S. 735, 743-744, 99 S.Ct. 2577, 61 L.Ed.2d 220 (1979) ; United States v. Miller, 425 U.S. 435, 443, 96 S.Ct. 1619, 48 L.Ed.2d 71 (1976). By these steps, the Court came to conclude, the Constitution does nothing to limit investigators from searching records you've entrusted to your bank, accountant, and maybe even your doctor.

*2262What's left of the Fourth Amendment? Today we use the Internet to do most everything. Smartphones make it easy to keep a calendar, correspond with friends, make calls, conduct banking, and even watch the game. Countless Internet companies maintain records about us and, increasingly, for us. Even our most private documents-those that, in other eras, we would have locked safely in a desk drawer or destroyed-now reside on third party servers. Smith and Miller teach that the police can review all of this material, on the theory that no one reasonably expects any of it will be kept private. But no one believes that, if they ever did.

What to do? It seems to me we could respond in at least three ways. The first is to ignore the problem, maintain Smith and Miller, and live with the consequences. If the confluence of these decisions and modern technology means our Fourth Amendment rights are reduced to nearly nothing, so be it. The second choice is to set Smith and Miller aside and try again using the Katz "reasonable expectation of privacy" jurisprudence that produced them. The third is to look for answers elsewhere.

*

Start with the first option. Smith held that the government's use of a pen register to record the numbers people dial on their phones doesn't infringe a reasonable expectation of privacy because that information is freely disclosed to the third party phone company. 442 U.S., at 743-744, 99 S.Ct. 2577. Miller held that a bank account holder enjoys no reasonable expectation of privacy in the bank's records of his account activity. That's true, the Court reasoned, "even if the information is revealed on the assumption that it will be used only for a limited purpose and the confidence placed in the third party will not be betrayed." 425 U.S., at 443, 96 S.Ct. 1619. Today the Court suggests that Smith and Miller distinguish between kinds of information disclosed to third parties and require courts to decide whether to "extend" those decisions to particular classes of information, depending on their sensitivity. See ante, at 2216 - 2221. But as the Sixth Circuit recognized and Justice KENNEDY explains, no balancing test of this kind can be found in Smith and Miller . See ante, at 2231 - 2232 (dissenting opinion). Those cases announced a categorical rule: Once you disclose information to third parties, you forfeit any reasonable expectation of privacy you might have had in it. And even if Smith and Miller did permit courts to conduct a balancing contest of the kind the Court now suggests, it's still hard to see how that would help the petitioner in this case. Why is someone's location when using a phone so much more sensitive than who he was talking to (Smith ) or what financial transactions he engaged in (Miller )? I do not know and the Court does not say.

The problem isn't with the Sixth Circuit's application of Smith and Miller but with the cases themselves. Can the government demand a copy of all your e-mails from Google or Microsoft without implicating your Fourth Amendment rights? Can it secure your DNA from 23andMe without a warrant or probable cause? Smith and Miller say yes it can-at least without running afoul of Katz . But that result strikes most lawyers and judges today-me included-as pretty unlikely. In the years since its adoption, countless scholars, too, have come to conclude that the "third-party doctrine is not only wrong, but horribly wrong." Kerr, The Case for the Third-Party Doctrine, 107 Mich. L. Rev. 561, 563, n. 5, 564 (2009) (collecting criticisms but defending the doctrine (footnotes omitted)). The reasons are obvious. "As an empirical statement about subjective *2263expectations of privacy," the doctrine is "quite dubious." Baude & Stern, The Positive Law Model of the Fourth Amendment, 129 Harv. L. Rev. 1821, 1872 (2016). People often do reasonably expect that information they entrust to third parties, especially information subject to confidentiality agreements, will be kept private. Meanwhile, if the third party doctrine is supposed to represent a normative assessment of when a person should expect privacy, the notion that the answer might be "never" seems a pretty unattractive societal prescription. Ibid.

What, then, is the explanation for our third party doctrine? The truth is, the Court has never offered a persuasive justification. The Court has said that by conveying information to a third party you " 'assum[e] the risk' " it will be revealed to the police and therefore lack a reasonable expectation of privacy in it. Smith, supra, at 744, 99 S.Ct. 2577. But assumption of risk doctrine developed in tort law. It generally applies when "by contract or otherwise [one] expressly agrees to accept a risk of harm" or impliedly does so by "manifest[ing] his willingness to accept" that risk and thereby "take[s] his chances as to harm which may result from it." Restatement (Second) of Torts §§ 496B, 496C(1), and Comment b (1965); see also 1 D. Dobbs, P. Hayden, & E. Bublick, Law of Torts §§ 235-236, pp. 841-850 (2d ed. 2017). That rationale has little play in this context. Suppose I entrust a friend with a letter and he promises to keep it secret until he delivers it to an intended recipient. In what sense have I agreed to bear the risk that he will turn around, break his promise, and spill its contents to someone else? More confusing still, what have I done to "manifest my willingness to accept" the risk that the government will pry the document from my friend and read it without his consent?

One possible answer concerns knowledge. I know that my friend might break his promise, or that the government might have some reason to search the papers in his possession. But knowing about a risk doesn't mean you assume responsibility for it. Whenever you walk down the sidewalk you know a car may negligently or recklessly veer off and hit you, but that hardly means you accept the consequences and absolve the driver of any damage he may do to you. Epstein, Privacy and the Third Hand: Lessons From the Common Law of Reasonable Expectations, 24 Berkeley Tech. L.J. 1199, 1204 (2009) ; see W. Keeton, D. Dobbs, R. Keeton, & D. Owen, Prosser & Keeton on Law of Torts 490 (5th ed.1984).

Some have suggested the third party doctrine is better understood to rest on consent than assumption of risk. "So long as a person knows that they are disclosing information to a third party," the argument goes, "their choice to do so is voluntary and the consent valid." Kerr, supra, at 588. I confess I still don't see it. Consenting to give a third party access to private papers that remain my property is not the same thing as consenting to a search of those papers by the government. Perhaps there are exceptions, like when the third party is an undercover government agent. See Murphy, The Case Against the Case Against the Third-Party Doctrine: A Response to Epstein and Kerr, 24 Berkeley Tech. L.J. 1239, 1252 (2009) ; cf. Hoffa v. United States, 385 U.S. 293, 87 S.Ct. 408, 17 L.Ed.2d 374 (1966). But otherwise this conception of consent appears to be just assumption of risk relabeled-you've "consented" to whatever risks are foreseeable.

Another justification sometimes offered for third party doctrine is clarity. You (and the police) know exactly how much protection you have in information confided *2264to others: none. As rules go, "the king always wins" is admirably clear. But the opposite rule would be clear too: Third party disclosures never diminish Fourth Amendment protection (call it "the king always loses"). So clarity alone cannot justify the third party doctrine.

In the end, what do Smith and Miller add up to? A doubtful application of Katz that lets the government search almost whatever it wants whenever it wants. The Sixth Circuit had to follow that rule and faithfully did just that, but it's not clear why we should.

*

There's a second option. What if we dropped Smith and Miller 's third party doctrine and retreated to the root Katz question whether there is a "reasonable expectation of privacy" in data held by third parties? Rather than solve the problem with the third party doctrine, I worry this option only risks returning us to its source: After all, it was Katz that produced Smith and Miller in the first place.

Katz's problems start with the text and original understanding of the Fourth Amendment, as Justice THOMAS thoughtfully explains today. Ante, at 2237 - 2244 (dissenting opinion). The Amendment's protections do not depend on the breach of some abstract "expectation of privacy" whose contours are left to the judicial imagination. Much more concretely, it protects your "person," and your "houses, papers, and effects." Nor does your right to bring a Fourth Amendment claim depend on whether a judge happens to agree that your subjective expectation to privacy is a "reasonable" one. Under its plain terms, the Amendment grants you the right to invoke its guarantees whenever one of your protected things (your person, your house, your papers, or your effects) is unreasonably searched or seized. Period.

History too holds problems for Katz . Little like it can be found in the law that led to the adoption of the Fourth Amendment or in this Court's jurisprudence until the late 1960s. The Fourth Amendment came about in response to a trio of 18th century cases "well known to the men who wrote and ratified the Bill of Rights, [and] famous throughout the colonial population." Stuntz, The Substantive Origins of Criminal Procedure, 105 Yale L.J. 393, 397 (1995). The first two were English cases invalidating the Crown's use of general warrants to enter homes and search papers. Entick v. Carrington, 19 How. St. Tr. 1029 (K.B. 1765); Wilkes v. Wood, 19 How. St. Tr. 1153 (K.B. 1763); see W. Cuddihy, The Fourth Amendment: Origins and Original Meaning 439-487 (2009); Boyd v. United States, 116 U.S. 616, 625-630, 6 S.Ct. 524, 29 L.Ed. 746 (1886). The third was American: the Boston Writs of Assistance Case, which sparked colonial outrage at the use of writs permitting government agents to enter houses and business, breaking open doors and chests along the way, to conduct searches and seizures-and to force third parties to help them. Stuntz, supra, at 404-409 ; M. Smith, The Writs of Assistance Case (1978). No doubt the colonial outrage engendered by these cases rested in part on the government's intrusion upon privacy. But the framers chose not to protect privacy in some ethereal way dependent on judicial intuitions. They chose instead to protect privacy in particular places and things-"persons, houses, papers, and effects"-and against particular threats-"unreasonable" governmental "searches and seizures." See Entick, supra, at 1066 ("Papers are the owner's goods and chattels; they are his dearest property; and so far from enduring a seizure, that they will hardly bear an inspection"); see also ante, at 2235 - 2246 (THOMAS, J., dissenting).

*2265Even taken on its own terms, Katz has never been sufficiently justified. In fact, we still don't even know what its "reasonable expectation of privacy" test is . Is it supposed to pose an empirical question (what privacy expectations do people actually have) or a normative one (what expectations should they have)? Either way brings problems. If the test is supposed to be an empirical one, it's unclear why judges rather than legislators should conduct it. Legislators are responsive to their constituents and have institutional resources designed to help them discern and enact majoritarian preferences. Politically insulated judges come armed with only the attorneys' briefs, a few law clerks, and their own idiosyncratic experiences. They are hardly the representative group you'd expect (or want) to be making empirical judgments for hundreds of millions of people. Unsurprisingly, too, judicial judgments often fail to reflect public views. See Slobogin & Schumacher, Reasonable Expectations of Privacy and Autonomy in Fourth Amendment Cases: An Empirical Look at "Understandings Recognized and Permitted by Society," 42 Duke L.J. 727, 732, 740-742 (1993). Consider just one example. Our cases insist that the seriousness of the offense being investigated does not reduce Fourth Amendment protection. Mincey v. Arizona, 437 U.S. 385, 393-394, 98 S.Ct. 2408, 57 L.Ed.2d 290 (1978). Yet scholars suggest that most people are more tolerant of police intrusions when they investigate more serious crimes. See Blumenthal, Adya, & Mogle, The Multiple Dimensions of Privacy: Testing Lay "Expectations of Privacy," 11 U. Pa. J. Const. L. 331, 352-353 (2009). And I very much doubt that this Court would be willing to adjust its Katz cases to reflect these findings even if it believed them.

Maybe, then, the Katz test should be conceived as a normative question. But if that's the case, why (again) do judges, rather than legislators, get to determine whether society should be prepared to recognize an expectation of privacy as legitimate? Deciding what privacy interests should be recognized often calls for a pure policy choice, many times between incommensurable goods-between the value of privacy in a particular setting and society's interest in combating crime. Answering questions like that calls for the exercise of raw political will belonging to legislatures, not the legal judgment proper to courts. See The Federalist No. 78, p. 465 (C. Rossiter ed. 1961) (A. Hamilton). When judges abandon legal judgment for political will we not only risk decisions where "reasonable expectations of privacy" come to bear "an uncanny resemblance to those expectations of privacy" shared by Members of this Court. Minnesota v. Carter, 525 U.S. 83, 97, 119 S.Ct. 469, 142 L.Ed.2d 373 (1998) (Scalia, J., concurring). We also risk undermining public confidence in the courts themselves.

My concerns about Katz come with a caveat. Sometimes, I accept, judges may be able to discern and describe existing societal norms. See, e.g., Florida v. Jardines, 569 U.S. 1, 8, 133 S.Ct. 1409, 185 L.Ed.2d 495 (2013) (inferring a license to enter on private property from the " 'habits of the country' " (quoting McKee v. Gratz, 260 U.S. 127, 136, 43 S.Ct. 16, 67 L.Ed. 167 (1922) )); Sachs, Finding Law, 107 Cal. L. Rev. (forthcoming 2019), online at https://ssrn.com/abstract=3064443 (as last visited June 19, 2018). That is particularly true when the judge looks to positive law rather than intuition for guidance on social norms. See Byrd v. United States, 584 U.S. ----, ---- - ----, 138 S.Ct. 1518, 1527, --- L.Ed.2d ---- (2018) ("general property-based concept[s] guid[e] the resolution of this case"). So there may be some occasions where Katz is capable of principled application-*2266though it may simply wind up approximating the more traditional option I will discuss in a moment. Sometimes it may also be possible to apply Katz by analogizing from precedent when the line between an existing case and a new fact pattern is short and direct. But so far this Court has declined to tie itself to any significant restraints like these. See ante, at 2214, n. 1 ("[W]hile property rights are often informative, our cases by no means suggest that such an interest is 'fundamental' or 'dispositive' in determining which expectations of privacy are legitimate").

As a result, Katz has yielded an often unpredictable-and sometimes unbelievable-jurisprudence. Smith and Miller are only two examples; there are many others. Take Florida v. Riley, 488 U.S. 445, 109 S.Ct. 693, 102 L.Ed.2d 835 (1989), which says that a police helicopter hovering 400 feet above a person's property invades no reasonable expectation of privacy. Try that one out on your neighbors. Or California v. Greenwood, 486 U.S. 35, 108 S.Ct. 1625, 100 L.Ed.2d 30 (1988), which holds that a person has no reasonable expectation of privacy in the garbage he puts out for collection. In that case, the Court said that the homeowners forfeited their privacy interests because "[i]t is common knowledge that plastic garbage bags left on or at the side of a public street are readily accessible to animals, children, scavengers, snoops, and other members of the public." Id., at 40, 108 S.Ct. 1625 (footnotes omitted). But the habits of raccoons don't prove much about the habits of the country. I doubt, too, that most people spotting a neighbor rummaging through their garbage would think they lacked reasonable grounds to confront the rummager. Making the decision all the stranger, California state law expressly protected a homeowner's property rights in discarded trash. Id., at 43, 108 S.Ct. 1625. Yet rather than defer to that as evidence of the people's habits and reasonable expectations of privacy, the Court substituted its own curious judgment.

Resorting to Katz in data privacy cases threatens more of the same. Just consider. The Court today says that judges should use Katz 's reasonable expectation of privacy test to decide what Fourth Amendment rights people have in cell-site location information, explaining that "no single rubric definitively resolves which expectations of privacy are entitled to protection." Ante, at 2213 - 2214. But then it offers a twist. Lower courts should be sure to add two special principles to their Katz calculus: the need to avoid "arbitrary power" and the importance of "plac[ing] obstacles in the way of a too permeating police surveillance." Ante, at 2214 (internal quotation marks omitted). While surely laudable, these principles don't offer lower courts much guidance. The Court does not tell us, for example, how far to carry either principle or how to weigh them against the legitimate needs of law enforcement. At what point does access to electronic data amount to "arbitrary" authority? When does police surveillance become "too permeating"? And what sort of "obstacles" should judges "place" in law enforcement's path when it does? We simply do not know.

The Court's application of these principles supplies little more direction. The Court declines to say whether there is any sufficiently limited period of time "for which the Government may obtain an individual's historical [location information] free from Fourth Amendment scrutiny." Ante, at 2217, n. 3; see ante, at 2216 - 2219. But then it tells us that access to seven days' worth of information does trigger Fourth Amendment scrutiny-even though here the carrier "produced only two days of records." Ante, at 2217, n. 3. Why is the relevant fact the seven days of *2267information the government asked for instead of the two days of information the government actually saw ? Why seven days instead of ten or three or one? And in what possible sense did the government "search" five days' worth of location information it was never even sent? We do not know.

Later still, the Court adds that it can't say whether the Fourth Amendment is triggered when the government collects "real-time CSLI or 'tower dumps' (a download of information on all the devices that connected to a particular cell site during a particular interval)."Ante, at 2220. But what distinguishes historical data from real-time data, or seven days of a single person's data from a download of everyone 's data over some indefinite period of time? Why isn't a tower dump the paradigmatic example of "too permeating police surveillance" and a dangerous tool of "arbitrary" authority-the touchstones of the majority's modified Katz analysis? On what possible basis could such mass data collection survive the Court's test while collecting a single person's data does not? Here again we are left to guess. At the same time, though, the Court offers some firm assurances. It tells us its decision does not "call into question conventional surveillance techniques and tools, such as security cameras." Ibid. That, however, just raises more questions for lower courts to sort out about what techniques qualify as "conventional" and why those techniques would be okay even if they lead to "permeating police surveillance" or "arbitrary police power."

Nor is this the end of it. After finding a reasonable expectation of privacy, the Court says there's still more work to do. Courts must determine whether to "extend" Smith and Miller to the circumstances before them. Ante, at 2216, 2219 - 2220. So apparently Smith and Miller aren't quite left for dead; they just no longer have the clear reach they once did. How do we measure their new reach? The Court says courts now must conduct a second Katz -like balancing inquiry, asking whether the fact of disclosure to a third party outweighs privacy interests in the "category of information" so disclosed. Ante, at 2218, 2219 - 2220. But how are lower courts supposed to weigh these radically different interests? Or assign values to different categories of information? All we know is that historical cell-site location information (for seven days, anyway) escapes Smith and Miller 's shorn grasp, while a lifetime of bank or phone records does not. As to any other kind of information, lower courts will have to stay tuned.

In the end, our lower court colleagues are left with two amorphous balancing tests, a series of weighty and incommensurable principles to consider in them, and a few illustrative examples that seem little more than the product of judicial intuition. In the Court's defense, though, we have arrived at this strange place not because the Court has misunderstood Katz . Far from it. We have arrived here because this is where Katz inevitably leads.

*

There is another way. From the founding until the 1960s, the right to assert a Fourth Amendment claim didn't depend on your ability to appeal to a judge's personal sensibilities about the "reasonableness" of your expectations or privacy. It was tied to the law. Jardines, 569 U.S., at 11, 133 S.Ct. 1409 ; United States v. Jones, 565 U.S. 400, 405, 132 S.Ct. 945, 181 L.Ed.2d 911 (2012). The Fourth Amendment protects "the right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures." True to those words and their original understanding, the traditional approach *2268asked if a house, paper or effect was yours under law. No more was needed to trigger the Fourth Amendment. Though now often lost in Katz 's shadow, this traditional understanding persists. Katz only "supplements, rather than displaces the traditional property-based understanding of the Fourth Amendment." Byrd, 584 U.S., at ----, 138 S.Ct., at 1526 (internal quotation marks omitted); Jardines, supra, at 11, 133 S.Ct. 1409 (same); Soldal v. Cook County, 506 U.S. 56, 64, 113 S.Ct. 538, 121 L.Ed.2d 450 (1992) (Katz did not "snuf[f] out the previously recognized protection for property under the Fourth Amendment").

Beyond its provenance in the text and original understanding of the Amendment, this traditional approach comes with other advantages. Judges are supposed to decide cases based on "democratically legitimate sources of law"-like positive law or analogies to items protected by the enacted Constitution-rather than "their own biases or personal policy preferences." Pettys, Judicial Discretion in Constitutional Cases, 26 J.L. & Pol. 123, 127 (2011). A Fourth Amendment model based on positive legal rights "carves out significant room for legislative participation in the Fourth Amendment context," too, by asking judges to consult what the people's representatives have to say about their rights. Baude & Stern, 129 Harv. L. Rev., at 1852. Nor is this approach hobbled by Smith and Miller, for those cases are just limitations on Katz, addressing only the question whether individuals have a reasonable expectation of privacy in materials they share with third parties. Under this more traditional approach, Fourth Amendment protections for your papers and effects do not automatically disappear just because you share them with third parties.

Given the prominence Katz has claimed in our doctrine, American courts are pretty rusty at applying the traditional approach to the Fourth Amendment. We know that if a house, paper, or effect is yours, you have a Fourth Amendment interest in its protection. But what kind of legal interest is sufficient to make something yours ? And what source of law determines that? Current positive law? The common law at 1791, extended by analogy to modern times? Both? See Byrd, supra, at ---- - ----, 138 S.Ct., at 1531 (THOMAS, J., concurring); cf. Re, The Positive Law Floor, 129 Harv. L. Rev. Forum 313 (2016). Much work is needed to revitalize this area and answer these questions. I do not begin to claim all the answers today, but (unlike with Katz ) at least I have a pretty good idea what the questions are . And it seems to me a few things can be said.

First, the fact that a third party has access to or possession of your papers and effects does not necessarily eliminate your interest in them. Ever hand a private document to a friend to be returned? Toss your keys to a valet at a restaurant? Ask your neighbor to look after your dog while you travel? You would not expect the friend to share the document with others; the valet to lend your car to his buddy; or the neighbor to put Fido up for adoption. Entrusting your stuff to others is a bailment . A bailment is the "delivery of personal property by one person (the bailor ) to another (the bailee ) who holds the property for a certain purpose." Black's Law Dictionary 169 (10th ed. 2014); J. Story, Commentaries on the Law of Bailments § 2, p. 2 (1832) ("a bailment is a delivery of a thing in trust for some special object or purpose, and upon a contract, expressed or implied, to conform to the object or purpose of the trust"). A bailee normally owes a legal duty to keep the item safe, according to the terms of the parties' contract if they have one, and according to the "implication[s] from their *2269conduct" if they don't. 8 C.J. S., Bailments § 36, pp. 468-469 (2017). A bailee who uses the item in a different way than he's supposed to, or against the bailor's instructions, is liable for conversion. Id., § 43, at 481; see Goad v. Harris, 207 Ala. 357, 92 So. 546 (1922) ; Knight v. Seney, 290 Ill. 11, 17, 124 N.E. 813, 815-816 (1919) ; Baxter v. Woodward, 191 Mich. 379, 385, 158 N.W. 137, 139 (1916). This approach is quite different from Smith and Miller 's (counter)-intuitive approach to reasonable expectations of privacy; where those cases extinguish Fourth Amendment interests once records are given to a third party, property law may preserve them.

Our Fourth Amendment jurisprudence already reflects this truth. In Ex parte Jackson, 96 U.S. 727, 24 L.Ed. 877 (1878), this Court held that sealed letters placed in the mail are "as fully guarded from examination and inspection, except as to their outward form and weight, as if they were retained by the parties forwarding them in their own domiciles." Id., at 733. The reason, drawn from the Fourth Amendment's text, was that "[t]he constitutional guaranty of the right of the people to be secure in their papers against unreasonable searches and seizures extends to their papers, thus closed against inspection, wherever they may be ." Ibid. (emphasis added). It did not matter that letters were bailed to a third party (the government, no less). The sender enjoyed the same Fourth Amendment protection as he does "when papers are subjected to search in one's own household." Ibid.

These ancient principles may help us address modern data cases too. Just because you entrust your data-in some cases, your modern-day papers and effects-to a third party may not mean you lose any Fourth Amendment interest in its contents. Whatever may be left of Smith and Miller, few doubt that e-mail should be treated much like the traditional mail it has largely supplanted-as a bailment in which the owner retains a vital and protected legal interest. See ante, at 2230 (KENNEDY, J., dissenting) (noting that enhanced Fourth Amendment protection may apply when the "modern-day equivalents of an individual's own 'papers' or 'effects' ... are held by a third party" through "bailment"); ante, at 2259, n. 6 (ALITO, J., dissenting) (reserving the question whether Fourth Amendment protection may apply in the case of "bailment" or when "someone has entrusted papers he or she owns ... to the safekeeping of another"); United States v. Warshak, 631 F.3d 266, 285-286 (C.A.6 2010) (relying on an analogy to Jackson to extend Fourth Amendment protection to e-mail held by a third party service provider).

Second, I doubt that complete ownership or exclusive control of property is always a necessary condition to the assertion of a Fourth Amendment right. Where houses are concerned, for example, individuals can enjoy Fourth Amendment protection without fee simple title. Both the text of the Amendment and the common law rule support that conclusion. "People call a house 'their' home when legal title is in the bank, when they rent it, and even when they merely occupy it rent free." Carter, 525 U.S., at 95-96, 119 S.Ct. 469 (Scalia, J., concurring). That rule derives from the common law. Oystead v. Shed, 13 Mass. 520, 523 (1816) (explaining, citing "[t]he very learned judges, Foster, Hale, and Coke, " that the law "would be as much disturbed by a forcible entry to arrest a boarder or a servant, who had acquired, by contract, express or implied, a right to enter the house at all times, and to remain in it as long as they please, as if the object were to arrest the master of the house or his children"). That is why tenants and resident family members-though they have no legal title-have standing to complain *2270about searches of the houses in which they live. Chapman v. United States, 365 U.S. 610, 616-617, 81 S.Ct. 776, 5 L.Ed.2d 828 (1961), Bumper v. North Carolina, 391 U.S. 543, 548, n. 11, 88 S.Ct. 1788, 20 L.Ed.2d 797 (1968).

Another point seems equally true: just because you have to entrust a third party with your data doesn't necessarily mean you should lose all Fourth Amendment protections in it. Not infrequently one person comes into possession of someone else's property without the owner's consent. Think of the finder of lost goods or the policeman who impounds a car. The law recognizes that the goods and the car still belong to their true owners, for "where a person comes into lawful possession of the personal property of another, even though there is no formal agreement between the property's owner and its possessor, the possessor will become a constructive bailee when justice so requires." Christensen v. Hoover, 643 P.2d 525, 529 (Colo.1982) (en banc); Laidlaw, Principles of Bailment, 16 Cornell L.Q. 286 (1931). At least some of this Court's decisions have already suggested that use of technology is functionally compelled by the demands of modern life, and in that way the fact that we store data with third parties may amount to a sort of involuntary bailment too. See ante, at 2217 - 2218 (majority opinion); Riley v. California, 573 U.S. ----, ----, 134 S.Ct. 2473, 2484, 189 L.Ed.2d 430 (2014).

Third, positive law may help provide detailed guidance on evolving technologies without resort to judicial intuition. State (or sometimes federal) law often creates rights in both tangible and intangible things. See Ruckelshaus v. Monsanto Co., 467 U.S. 986, 1001, 104 S.Ct. 2862, 81 L.Ed.2d 815 (1984). In the context of the Takings Clause we often ask whether those state-created rights are sufficient to make something someone's property for constitutional purposes. See id., at 1001-1003, 104 S.Ct. 2862 ; Louisville Joint Stock Land Bank v. Radford, 295 U.S. 555, 590-595, 55 S.Ct. 854, 79 L.Ed. 1593 (1935). A similar inquiry may be appropriate for the Fourth Amendment. Both the States and federal government are actively legislating in the area of third party data storage and the rights users enjoy. See, e.g., Stored Communications Act, 18 U.S.C. § 2701 et seq. ; Tex. Prop.Code Ann. § 111.004(12) (West 2017) (defining "[p]roperty" to include "property held in any digital or electronic medium"). State courts are busy expounding common law property principles in this area as well. E.g., Ajemian v. Yahoo!, Inc., 478 Mass. 169, 170, 84 N.E.3d 766, 768 (2017) (e-mail account is a "form of property often referred to as a 'digital asset' "); Eysoldt v. ProScan Imaging, 194 Ohio App.3d 630, 638, 2011-Ohio-2359, 957 N.E.2d 780, 786 (2011) (permitting action for conversion of web account as intangible property). If state legislators or state courts say that a digital record has the attributes that normally make something property, that may supply a sounder basis for judicial decisionmaking than judicial guesswork about societal expectations.

Fourth, while positive law may help establish a person's Fourth Amendment interest there may be some circumstances where positive law cannot be used to defeat it. Ex parte Jackson reflects that understanding. There this Court said that "[n]o law of Congress" could authorize letter carriers "to invade the secrecy of letters." 96 U.S., at 733. So the post office couldn't impose a regulation dictating that those mailing letters surrender all legal interests in them once they're deposited in a mailbox. If that is right, Jackson suggests the existence of a constitutional floor below which Fourth Amendment rights may not descend. Legislatures cannot *2271pass laws declaring your house or papers to be your property except to the extent the police wish to search them without cause. As the Court has previously explained, "we must 'assur[e] preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted.' " Jones, 565 U.S., at 406, 132 S.Ct. 945 (quoting Kyllo v. United States, 533 U.S. 27, 34, 121 S.Ct. 2038, 150 L.Ed.2d 94 (2001) ). Nor does this mean protecting only the specific rights known at the founding; it means protecting their modern analogues too. So, for example, while thermal imaging was unknown in 1791, this Court has recognized that using that technology to look inside a home constitutes a Fourth Amendment "search" of that "home" no less than a physical inspection might. Id., at 40, 121 S.Ct. 2038.

Fifth, this constitutional floor may, in some instances, bar efforts to circumvent the Fourth Amendment's protection through the use of subpoenas. No one thinks the government can evade Jackson 's prohibition on opening sealed letters without a warrant simply by issuing a subpoena to a postmaster for "all letters sent by John Smith" or, worse, "all letters sent by John Smith concerning a particular transaction." So the question courts will confront will be this: What other kinds of records are sufficiently similar to letters in the mail that the same rule should apply?

It may be that, as an original matter, a subpoena requiring the recipient to produce records wasn't thought of as a "search or seizure" by the government implicating the Fourth Amendment, see ante, at 2247 - 2253 (opinion of ALITO, J.), but instead as an act of compelled self-incrimination implicating the Fifth Amendment, see United States v. Hubbell, 530 U.S. 27, 49-55, 120 S.Ct. 2037, 147 L.Ed.2d 24 (2000) (THOMAS, J., dissenting); Nagareda, Compulsion "To Be a Witness" and the Resurrection of Boyd, 74 N.Y.U. L. Rev. 1575, 1619, and n. 172 (1999). But the common law of searches and seizures does not appear to have confronted a case where private documents equivalent to a mailed letter were entrusted to a bailee and then subpoenaed. As a result, "[t]he common-law rule regarding subpoenas for documents held by third parties entrusted with information from the target is ... unknown and perhaps unknowable." Dripps, Perspectives on The Fourth Amendment Forty Years Later: Toward the Realization of an Inclusive Regulatory Model, 100 Minn. L. Rev. 1885, 1922 (2016). Given that (perhaps insoluble) uncertainty, I am content to adhere to Jackson and its implications for now.

To be sure, we must be wary of returning to the doctrine of Boyd v. United States, 116 U.S. 616, 6 S.Ct. 524, 29 L.Ed. 746. Boyd invoked the Fourth Amendment to restrict the use of subpoenas even for ordinary business records and, as Justice ALITO notes, eventually proved unworkable. See ante, at 2253 (dissenting opinion); 3 W. LaFave, J. Israel, N. King, & O. Kerr, Criminal Procedure § 8.7(a), pp. 185-187 (4th ed. 2015). But if we were to overthrow Jackson too and deny Fourth Amendment protection to any subpoenaed materials, we would do well to reconsider the scope of the Fifth Amendment while we're at it. Our precedents treat the right against self-incrimination as applicable only to testimony, not the production of incriminating evidence. See Fisher v. United States, 425 U.S. 391, 401, 96 S.Ct. 1569, 48 L.Ed.2d 39 (1976). But there is substantial evidence that the privilege against self-incrimination was also originally understood to protect a person from being forced to turn over potentially incriminating evidence. Nagareda, supra, at 1605-1623 ; Rex v. Purnell, 96 Eng. Rep. 20 (K.B. 1748); Slobogin, Privacy at Risk 145 (2007).

*2272*

What does all this mean for the case before us? To start, I cannot fault the Sixth Circuit for holding that Smith and Miller extinguish any Katz -based Fourth Amendment interest in third party cell-site data. That is the plain effect of their categorical holdings. Nor can I fault the Court today for its implicit but unmistakable conclusion that the rationale of Smith and Miller is wrong; indeed, I agree with that. The Sixth Circuit was powerless to say so, but this Court can and should. At the same time, I do not agree with the Court's decision today to keep Smith and Miller on life support and supplement them with a new and multilayered inquiry that seems to be only Katz -squared. Returning there, I worry, promises more trouble than help. Instead, I would look to a more traditional Fourth Amendment approach. Even if Katz may still supply one way to prove a Fourth Amendment interest, it has never been the only way. Neglecting more traditional approaches may mean failing to vindicate the full protections of the Fourth Amendment.

Our case offers a cautionary example. It seems to me entirely possible a person's cell-site data could qualify as his papers or effects under existing law. Yes, the telephone carrier holds the information. But 47 U.S.C. § 222 designates a customer's cell-site location information as "customer proprietary network information" (CPNI), § 222(h)(1)(A), and gives customers certain rights to control use of and access to CPNI about themselves. The statute generally forbids a carrier to "use, disclose, or permit access to individually identifiable" CPNI without the customer's consent, except as needed to provide the customer's telecommunications services. § 222(c)(1). It also requires the carrier to disclose CPNI "upon affirmative written request by the customer, to any person designated by the customer." § 222(c)(2). Congress even afforded customers a private cause of action for damages against carriers who violate the Act's terms. § 207. Plainly, customers have substantial legal interests in this information, including at least some right to include, exclude, and control its use. Those interests might even rise to the level of a property right.

The problem is that we do not know anything more. Before the district court and court of appeals, Mr. Carpenter pursued only a Katz "reasonable expectations" argument. He did not invoke the law of property or any analogies to the common law, either there or in his petition for certiorari. Even in his merits brief before this Court, Mr. Carpenter's discussion of his positive law rights in cell-site data was cursory. He offered no analysis, for example, of what rights state law might provide him in addition to those supplied by § 222. In these circumstances, I cannot help but conclude-reluctantly-that Mr. Carpenter forfeited perhaps his most promising line of argument.

Unfortunately, too, this case marks the second time this Term that individuals have forfeited Fourth Amendment arguments based on positive law by failing to preserve them. See Byrd, 584 U.S., at ----, 138 S.Ct., at 1526. Litigants have had fair notice since at least United States v. Jones (2012) and Florida v. Jardines (2013) that arguments like these may vindicate Fourth Amendment interests even where Katz arguments do not. Yet the arguments have gone unmade, leaving courts to the usual Katz handwaving. These omissions do not serve the development of a sound or fully protective Fourth Amendment jurisprudence.