Chatrie v. United StatesChatrie v. United States
NOTE: Where it is feasible, a syllabus (headnote) will be released, as is being done in connection with this case, at the time the opinion is issued. The syllabus constitutes no part of the opinion of the Court but has been prepared by the Reporter of Decisions for the convenience of the reader. See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.
SUPREME COURT OF THE UNITED STATES
Syllabus
CHATRIE v. UNITED STATES
On May 20, 2019, a man robbed a credit union in Midlothian, Virginia. Local police officers learned from witness interviews and surveillance footage that the robber had approached the credit union from a corner of an adjacent church while appearing to talk on a cell phone, but they could not find out anything more, and the robber remained at large. On June 14, the police officers applied to a Virginia magistrate for a geofence warrant directed to Google, which would require Google to hand over data about the cell phones located within a 150-meter radius of the credit union—the so-called “geofence”—near the time of the crime. The application described the cell-phone location data Google collects through a service called Location History, which records the location of a user’s cell phone every two minutes or so. The application also explained how that cell-phone location data could help identify the robber, possible accomplices, or additional witnesses. The warrant described a three-step process that the police would follow: at step one, Google would produce anonymized location data for all cell phones within the geofence 30 minutes before to 30 minutes after the robbery; at step two, officers would attempt to narrow the list, and Google would provide additional anonymized data for that narrowed list, consisting of cell-phone locations both inside and outside the geofence during a two-hour period surrounding the robbery; and at step three, officers would further narrow the list, and Google would turn over identifying information, including names and phone numbers, for users on the final list. The magistrate issued the warrant, and through this process, Google ultimately produced three cell-phone users’ identifying information, including petitioner Okello Chatrie, whose location data showed that he entered the geofence about ten minutes before the robbery and headed toward a residential area immediately after leaving
Following further police work, a federal grand jury charged Chatrie with robbery and related firearms offenses, and he moved to suppress the information the police obtained from Google. According to Chatrie, the officers had acquired that data through a Fourth Amendment search, and the warrant ostensibly authorizing that search was invalid. The District Court found that the geofence warrant “plainly violates the rights enshrined in [the Fourth] Amendment” but denied the motion based on the good-faith exception to the exclusionary rule. 590 F. Supp. 3d 901, 905, 937–938. A divided panel of the Fourth Circuit affirmed on different reasoning, holding that no search occurred because Chatrie “did not have a reasonable expectation of privacy in two hours’ worth of Location History data voluntarily exposed to Google.” 107 F. 4th 319, 325. The Fourth Circuit granted rehearing en banc and affirmed in a one-sentence per curiam, with the court dividing evenly on whether a Fourth Amendment search had occurred. This Court granted certiorari solely on the question whether the police violated the Fourth Amendment in obtaining Chatrie’s location data.
Held: Police officers conducted a Fourth Amendment search when they acquired Chatrie’s location data from Google because an individual has a reasonable expectation of privacy in his cell-phone location information. Pp. 10–33.
(a) The Fourth Amendment protects individuals’ reasonable expectations of privacy, and governmental “intrusion into that private sphere generally qualifies as a search.” Carpenter v. United States, 585 U. S. 296, 304. The Amendment’s “basic purpose” is “to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials,” id., at 303, and it was designed “to place obstacles in the way of a too permeating police surveillance,” United States v. Di Re, 332 U. S. 581, 595. Pp. 10–29.
(1) In Carpenter, this Court held that accessing cell-site location information (CSLI) constitutes a Fourth Amendment search because “individuals have a reasonable expectation of privacy in the whole of their physical movements,” 585 U. S., at 310. The Court reasoned that CSLI provides a “detailed” and “encyclopedic” portrait of a person’s whereabouts, id., at 309, and, with that, “an intimate window into a person’s life,” id., at 311. Because people “compulsively carry” their cell phones “all the time,” the Court explained, a cell phone “tracks nearly exactly the movements of its owner,” and thus “faithfully follows” him not only through “public thoroughfares [but] into private residences, doctor’s offices, political headquarters, and other potentially revealing locales.” Ibid. The Court further observed that the “newfound tracking capacity” that CSLI gives the police “runs against everyone”—not just those “under investigation”—and “travel[s] back
(2) Everything Carpenter relied on to find that law enforcement officers conducted a Fourth Amendment search when they accessed CSLI records applies as well or better to the police’s accessing of Location History data. First, Location History provides an even more fine-tuned picture of a person’s movements, pinpointing location within around twenty meters rather than within sectors of one-eighth to four square miles; it records location every two minutes or so for a daily average of 720 chartings rather than 101; and it can estimate elevation to reveal which floor of a building a phone is on. Second, Location History allows police to reconstruct “retrospective[ly],” and with no real effort, people’s comings and goings in any area, enabling “tireless and absolute surveillance” of any number of people in any number of places. Carpenter, 585 U. S., at 312. And third, Location History implicates personal privacy interests even more than CSLI, because Location History is more the cell-phone user’s own. Most cell-phone users have no awareness of CSLI records, and would never try to retrieve them; by contrast, Google users regularly employ Location History as a personal journal. In that way, Location History resembles other private materials—e.g., emails, documents, photographs, or calendars—that even if stored on Google’s servers, a user reasonably views as his own and expects to be shielded from the “inquisitive eyes” of the government. Id., at 305. Pp. 16–18.
(3) The Government’s argument that accessing only a short amount of cell-phone location information does not count as a Fourth Amendment search fails. “[E]ven short-term monitoring” can provide “a wealth of detail about [a person’s] familial, political, professional, religious, and sexual associations,” United States v. Jones, 565 U. S. 400, 415, and this Court has never understood Fourth Amendment protections as kicking in only once an intrusion “goes too far,” Pennsylvania Coal Co. v. Mahon, 260 U. S. 393, 415. Where the Fourth Amendment applies, it applies regardless of “the quality or quantity of information” the government obtains. Kyllo v. United States, 533 U. S. 27, 37. That approach makes all the more sense when, as with Location History, law enforcement officials can select the time-limited set of materials they want from an all-encompassing database. Pp. 18–23.
(4) The Government argues that the so-called third-party doctrine precludes Chatrie from invoking the Fourth Amendment’s protections. The idea is that in “authoriz[ing] Google to collect, retain, and use” his location information, Chatrie lost his legitimate expectation of privacy, and therefore his right to complain of a search. Brief for United States
(b) The conclusion that a Fourth Amendment search occurred does not resolve this case, because the Fourth Amendment prohibits only searches that are “unreasonable.” When law enforcement officials undertake a search to discover evidence of a crime, the reasonableness standard generally requires that they seek a warrant from “a neutral and detached magistrate,” Johnson v. United States, 333 U. S. 10, 14, who may issue a warrant only when “probable cause is properly established and the scope of the authorized search is set out with particularity,” Kentucky v. King, 563 U. S. 452, 459. The warrant issued here, as described earlier, was an uncommon, multi-step one, and the parties have contested the legality of each stage of the search process it
136 F. 4th 100, vacated and remanded.
KAGAN, J., delivered the opinion of the Court, in which ROBERTS, C. J., and SOTOMAYOR, KAVANAUGH, and JACKSON, JJ., joined. JACKSON, J., filed a concurring opinion, in which SOTOMAYOR, J., joined. GORSUCH, J., filed an opinion concurring in the judgment. ALITO, J., filed a dissenting opinion, in which THOMAS, J., joined as to Part I, and in which BARRETT, J., joined as to Parts II–B, II–C–1, and II–C–2. BARRETT, J., filed a dissenting opinion.
NOTICE: This opinion is subject to formal revision before publication in the United States Reports. Readers are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, pio@supremecourt.gov, of any typographical or other formal errors.
JUSTICE KAGAN delivered the opinion of the Court.
In recent years, law enforcement officers have employed so-called geofence warrants to obtain information that technology companies collect about their users’ cell-phone locations. Suppose that investigators know a crime was committed at a particular place and time, but do not have a suspect. They may draw a “geofence”—a virtual perimeter—around the crime scene and get a warrant compelling a company to hand over data about the cell phones located in that area near the time of the crime. Following a process specified in the warrant, the company will turn over the cell-phone data and eventually identify by name one or more of the users thus disclosed.
The geofence warrant at issue here was directed to Google, and used to solve a bank robbery. Hundreds of millions of Google users have activated a service called Location History, which records the location of a user’s cell phone every two minutes or so. Through a geofence warrant, police officers required Google to turn over Location History data revealing cell phones within the vicinity of a bank at around the time it was robbed. At the end of the multi-step process described in the warrant, Google gave
Today, we consider how the Fourth Amendment applies to that use of a geofence warrant. Answering that question in full would mean deciding whether the police conducted a Fourth Amendment “search” when they acquired the cell-phone data leading to Chatrie’s arrest and, if so, whether that search was reasonable given the features of the warrant they employed. We decide the first part of that inquiry today, concluding that the police conducted a search when they gained access to Location History data. An individual has a reasonable expectation of privacy in records about his cell phone’s location, and police intrude on that constitutionally protected interest when they demand the information—even though for only a limited time, and from a third-party tech company. We leave to the Court of Appeals the further question whether, given the warrant issued, the search here was reasonable, meaning that each of its steps was properly described with particularity and found to be supported by probable cause.
I
A
Modern cell phones, we observed a dozen years ago, are “such a pervasive and insistent part of daily life that the proverbial visitor from Mars might conclude they were an important feature of human anatomy.” Riley v. California, 573 U. S. 373, 385 (2014). Since then, the percentage of Americans who own smartphones has only increased. Today, more than nine in ten Americans own a smartphone. See W. Bishop, Pew Research Center, Mobile Fact Sheet (Nov. 20, 2025) (91%); compare A. Smith, Pew Research Center, Smartphone Ownership—2013 Update (June 5, 2013) (56%). That means they are likely addicted to apps and other services, many of which collect and store
Among that information is a single fact most pertinent here: where the user’s cell phone is located at a given time. Apps of many kinds rely on that datum. Your maps app wants to help you navigate from Point A (where you are) to Point B (where you are going). Ride-sharing apps of course track your location when you are using them, and often do so even when you are not. Weather apps want to tell you about local conditions. Fast-food apps want to identify the closest burger and pizza joints. Fitness apps want to track your running routes. And so on.
This case concerns a form of cell-phone location data called “Location History,” which Google apps collect and store.1 Location History is what it sounds like—a time-stamped record of every place a cell phone has been. Every two minutes or so, Location History draws from an array of sources to log a cell phone’s location. Those sources include nearby Wi-Fi networks, Bluetooth beacons, and cell sites, as well as GPS and IP address information. When combined, the signals tracked can determine a cell phone’s location within 20 meters. They can also ascertain a phone’s elevation, and thus reveal which floor within a building the phone is on. By all accounts, those features make Location History “the most sweeping, granular, and comprehensive tool” existing today for collecting and storing location data. 590 F. Supp. 3d 901, 907 (ED Va. 2022).
Google repeatedly prompts users to enable Location History, and over 500 million users worldwide have done so. The first prompt comes when a user initially establishes a Google account. If that spur is ignored, another will arrive when a user sets up a Google app—like Google Assistant,
Google stores all Location History data in the cloud, rather than on a user’s device—though that choice makes no real difference to the user. “Cloud computing” refers to “the capacity of Internet-connected devices to display data stored on remote servers rather than on the device itself.” Riley, 573 U. S., at 397. Because it exists, Google can store information on its own servers, while the user can view it as if stored on his cell phone. Such remote storage, we have explained, is common: “Cell phone users often may not know whether particular information is stored on the device or in the cloud, and it generally makes little difference.” Ibid. So, for example, Google usually stores users’ emails, documents, and photographs on company servers instead of on individual devices. See Brief for Google LLC as Amicus Curiae 3, 37–38. And the same is true of the information generated by Location History, which is stored in a single central repository on Google’s servers.2 That data exists someplace remote, but a user sees it—and the content
B
In the last decade, Google’s Location History data has also served another function, though this one unknown to most users: That data, as obtained through a geofence warrant, can enable law enforcement officers to solve hard-to-solve crimes. Such a warrant, as earlier described, seeks information about the cell phones located in the vicinity of a crime scene at around the time the crime was committed. See supra, at 1. The goal, put simply, is to find out who was there and so who might have done it. (There are usually better ways to investigate an already-known suspect—like seeking only his location data.) And the mechanism is to use the offender’s cell phone as an identifying device. The warrant specifies a timeframe and maps an area (with the geofence as its perimeter), and demands information about the cell phones—and their users—present within it. There is some uncertainty about how often the technique in fact works. See Brief for Orin S. Kerr as Amicus Curiae 14 (Kerr Brief ). But its use among law enforcement officers has flourished. Google received its first geofence warrant in 2016. See 590 F. Supp. 3d, at 914. Two years later, it received 982; and two years after that, more than 11,000. See Google, Supplemental Information on Geofence Warrants in The United States (Aug. 2021), https://services.google.com/fh/files/misc/supplemental_information_geofence_warrants_united_states.pdf (archived at https://perma.cc/LN4P-KQJA). Though the details vary, each has made the
As those demands began to proliferate, Google worked with law enforcement officials to develop a three-step protocol to govern geofence warrants. At the first step, Google produces anonymized (i.e., no names attached) location data for all cell phones (or other devices) within the geofence—typically, a circle with a designated radius surrounding a latitude/longitude coordinate—during a specified timeframe. That data generally includes each phone’s latitude/longitude coordinate and corresponding timestamp; an estimate of that information’s accuracy; and a description of the information’s source (e.g., a Wi-Fi network, a cell site, or some other). The data at this stage shows each user’s location, every two minutes or so, within the geofence. At the second step of the process, officials review the data produced and typically ask Google to provide additional information for a subset of still-anonymized users. That new data is usually for a longer timeframe than first specified; it also shows the user’s location outside, as well as inside, the geofence. Finally, at the third step, officials demand the identities of a further subset of users—their names, email addresses, and phone numbers. Thus, the geofence warrant is designed to eventually produce a select number of identified users suspected of committing the crime under investigation.
C
On May 20, 2019, at about 4:50 p.m., a man robbed a credit union in Midlothian, Virginia. The robber presented a teller with a handwritten note demanding $100,000,
Local police officers responded to the scene and began an investigation. They learned, from witness interviews and surveillance-camera footage, that the robber had approached the credit union from a corner of an adjacent church, while appearing to talk on a cell phone. But they could not find out anything more, and the robber remained at large.
On June 14, the police officers thus applied to a Virginia magistrate for a geofence warrant directed to Google. The application described the cell-phone location data Google collects, and explained how that data could lead to identifying the robber, his possible accomplices, or additional witnesses to the crime. Success was particularly likely here, the application stated, because the robber appeared to be using his phone when he entered the credit union, and may even have been speaking with an accomplice. The officers’ proposed geofence was a circle with a radius of 150 meters surrounding the credit union.
The warrant application went on to describe the three-step process that the police would follow to obtain the location information sought. At step one, Google would produce anonymized location data for all cell phones within the geofence in the hour between 4:20 and 5:20 p.m. (30 minutes before to 30 minutes after the robbery). At step two, police officers would “attempt to narrow down the list [of devices] by reviewing the time stamped location coordinates for each [device] and comparing that against the known time and location information that is specific to this
The magistrate issued the warrant, and officers executed it in the manner prescribed. At the first stage of the process, Google gave up anonymized data for 19 users found within the geofence during the hour within which the robbery occurred. At the second stage, the officers winnowed the list to nine users. And Google produced anonymized data showing their movements both inside and outside the geofence for the extended two-hour period. At the third and last step, the police again narrowed the list, this time to three users. Google responded with their identifying information. One of the three was Chatrie. The location data showed that he entered the geofenced area about ten minutes before the robbery, and headed toward a residential area of town immediately after leaving the bank.
Following further police work, a federal grand jury charged Chatrie with robbery and related firearms offenses. He moved to suppress the information that the police had obtained from Google. According to Chatrie, the officers had acquired that data through a Fourth Amendment search, and the warrant ostensibly authorizing that search was invalid.
The District Court mainly agreed with Chatrie’s Fourth Amendment analysis, but still denied the motion to exclude the Location History evidence. Even though “this particular geofence warrant plainly violates the rights enshrined in [the Fourth] Amendment,” the court stated, the officers’
A divided panel of the Court of Appeals for the Fourth Circuit affirmed, but on different reasoning. The majority held that the government did not conduct a search and therefore did not need a warrant. That was so, the majority reasoned, because Chatrie “did not have a reasonable expectation of privacy in two hours’ worth of Location History data voluntarily exposed to Google.” 107 F. 4th 319, 325 (2024). Judge Wynn dissented, arguing that “the police intrusion into Chatrie’s Location History data” was “a search that triggered the Fourth Amendment’s protections,” and that the warrant issued was “so lacking in particularity and probable cause that it was invalid.” Id., at 339, 362, and n. 12.
After granting rehearing en banc, the Fourth Circuit affirmed in a one-sentence per curiam. See 136 F. 4th 100, 101 (2025) (“The judgment of the district court is AFFIRMED”). In multiple accompanying writings, the court divided evenly (7 to 7) on whether a Fourth Amendment search had occurred. Of the seven judges who thought it had, most believed the geofence warrant defective. But most also thought the exclusionary rule’s good-faith exception applied, so ruled against Chatrie anyway.
We granted certiorari solely on the question whether the police violated the Fourth Amendment in obtaining Chatrie’s location data, thus declining to consider the exclusionary rule issue. See 607 U. S. 1148 (2026). The disputed Fourth Amendment question divides into two parts. First, did law enforcement officials conduct a search under the Fourth Amendment when they acquired Chatrie’s location data from Google? We hold that they did because an individual has a legitimate expectation of privacy in his cell-
II
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 that Amendment, our precedents say, is “to
That purpose is central to decisions about whether a Fourth Amendment “search” has occurred. Our early search doctrine focused on whether law enforcement officials “obtain[ed] information by physically intruding”—that is, trespassing—on private property. United States v. Jones, 565 U. S. 400, 406–407, n. 3 (2012); see id., at 404–405. But the Court in Katz v. United States, 389 U. S. 347, 351 (1967), recognized that “the Fourth Amendment protects people, not places.” And so we have long held that “property rights are not the sole measure” of a constitutional violation; the Fourth Amendment “protect[s] certain expectations of privacy as well.” Soldal v. Cook County, 506 U. S. 56, 64 (1992); Carpenter, 585 U. S., at 304. “When an individual seeks to preserve something as private and his expectation of privacy is one that society is prepared to recognize as reasonable,” then governmental “intrusion into that private sphere generally qualifies as a search.” Ibid.
In recent decades, this Court has often confronted the challenge of adhering to those principles in the face of new technologies. “[I]nnovations in surveillance tools” have “enhanced the Government’s capacity to encroach upon areas normally guarded from inquisitive eyes.” Ibid. The Court, in response, 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 (2001). So in one decision, we rejected a “mechanical interpretation” of the Fourth Amendment to hold that the use of a thermal imager to detect heat coming
We begin with Carpenter in considering the Government’s front-line position here: that no warrant was needed to get Location History data from Google (although the police “prophylactically secured” one) because no Fourth Amendment search ever took place. See Brief for United States 14. We then explain why the result we reached in Carpenter once again follows. Contrary to the Government’s view, an individual has a legitimate expectation of privacy in the information Location History collects about his cell phone’s—meaning his own—movements. The police invade that expectation, and thus conduct a search, when they acquire that information, even though for only a limited period of time and even though via a third-party tech company.
A
The question presented in Carpenter was “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.” 585 U. S., at 300. The cell-phone records at issue were what is known as cell-site location information (CSLI). As we explained, CSLI is a “time-stamped record” generated each time a cell phone connects to a cell site. Id., at 301. Wireless carriers collect and store that information for their own business purposes (such as finding weak spots in
The Court began its analysis by reviewing what it had said about a different way of tracking “physical location and movements”: the use of a GPS device to monitor a vehicle. Id., at 306. In United States v. Jones, 565 U. S. 400, five Justices had agreed that such tracking counts as a Fourth Amendment search because “individuals have a reasonable expectation of privacy in the whole of their physical movements.” Carpenter, 585 U. S., at 310; see Jones, 565 U. S., at 430 (ALITO, J., concurring in judgment); id., at 415 (SOTOMAYOR, J., concurring).6 That made sense, the Carpenter Court thought, even though the movements occurred in public. Prior to the digital age, pursuing a suspect “for any extended period of time was difficult and costly and therefore rarely undertaken.” 585 U. S., at 310 (quoting Jones, 565 U. S., at 429 (opinion of ALITO, J.)). As a result, “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.” Carpenter, 585 U. S., at 310 (quoting Jones, 565 U. S., at 430 (opinion of ALITO, J.)).
It followed a fortiori, Carpenter held, that “[a]llowing government access to cell-site records contravenes” expectations of privacy. 585 U. S., at 311. To an even greater degree than GPS monitoring, CSLI can provide a full “record of the holder’s whereabouts” and, with that, “an intimate window into a person’s life.” Ibid. People, after all, “regularly leave their vehicles,” but they “compulsively carry” their cell phones “all the time.” Ibid. A cell phone thus “tracks nearly exactly the movements of its owner”: It “faithfully follows” him not only through “public thoroughfares [but] into private residences, doctor’s offices, political headquarters, and other potentially revealing locales.” Ibid. What is more, the “newfound tracking capacity” that CSLI gives the police “runs against everyone”—not just those “under investigation”—and “travel[s] back in time.” Id., at 312. Police officers need not decide in advance (as they do with GPS devices) who they want to follow and when. Instead, they can easily and cheaply—with “just the click of a button”—reconstruct any person’s movements “retrospective[ly].” Id., at 311–312. What in the past was “unknowable” suddenly becomes open to view, presenting formerly unimaginable “privacy concerns.” Ibid. The Court thus concluded: “[W]hen the Government accessed CSLI from the wireless carriers”—thereby obtaining a “detailed log” of where Carpenter had gone for seven days—“it invaded Carpenter’s reasonable expectation of privacy in the whole of his physical movements.” Id., at 312–313
The resemblances between CSLI and Location History, in their relationship to personal privacy, practically leap off the page. Everything Carpenter relied on to find that law enforcement officers conducted a Fourth Amendment search when they accessed wireless carriers’ CSLI records applies as well or better to the police’s accessing of Google’s Location History data.
First, Location History provides an even more fine-tuned picture of a person’s movements than CSLI. Carpenter noted that through CSLI records, police could “achieve[] near perfect surveillance” of an individual holding a cell phone. Id., at 311–312. But Location History is nearer perfect still. Here is one way of comparing the two: At any given time, CSLI placed Carpenter within a “sector ranging from one-eighth to four square miles,” whereas Location History pinpointed Chatrie’s location within around twenty meters, which is less than two percent of a mile. Id., at 312; see 1 App. 45, 3 id., at 173–174. Or here is another
And next, Location History also allows police officers to reconstruct “retrospective[ly],” and with no real effort, people’s comings and goings in any area. Id., at 312. As with CSLI, the Government need not decide in advance the kind of surveillance it should undertake, whether of a person or a site. “Whoever the suspect turns out to be,” Carpenter said of CSLI, “he has effectively been tailed every moment of every day.” Ibid. Likewise, as this case shows, wherever a location of interest turns out to be (whether a crime scene or a protest march or even a private home), it has effectively been surveilled for the same boundless time. Google’s Location History will be available to chart the movements of many individuals—or a few or one—within the vicinity, again at the “click of a button.” Id., at 311. Recall that in Jones, it was thought notable that law enforcement officials of an earlier age usually could not monitor every movement of an individual’s car, as a GPS device does. See supra, at 14–15; 565 U. S., at 430 (opinion of ALITO, J.); see also Carpenter, 585 U. S., at 312 (“In the past, attempts to reconstruct a person’s [prior] movements were limited“). Far less
Indeed, Location History records implicate those privacy interests still more than CSLI data because the former is more the individual’s own. Most cell-phone users have no awareness of CSLI records, and anyway would never try to retrieve them. The records are instead the province of wireless carriers, which maintain them for an array of business functions. See Carpenter, 585 U. S., at 301; supra, at 13–14. Location History information is different. No doubt, Google itself uses those records to improve the quality of its apps. But Google users, too, regularly employ Location History—for example, “to remind themselves of a restaurant they ate at two weeks ago, the time they were last at a friend’s home, the sites they saw on vacation, or the distance they walked on a particular day.” Brief for Google LLC as Amicus Curiae 8. The records thus serve as a personal journal of a user’s movements, which that user consults (and even can edit) for his own purposes. See id., at 10. In that way, Location History resembles other private materials—think of emails, documents, photographs, or calendars—that even if stored on Google’s servers, a user reasonably views as his own. And as a result, that he reasonably expects to be shielded from the “inquisitive eyes” of the government. Carpenter, 585 U. S., at 305.
C
The Government, not much contesting any of the above, principally argues on a different ground: that accessing only a short amount of cell-phone location information (whether Location History or CSLI) does not count as a Fourth Amendment search. (The dissent likewise contends
Still more fundamentally, we have never understood Fourth Amendment protections as kicking in only once an intrusion “goes too far.” Pennsylvania Coal Co. v. Mahon, 260 U. S. 393, 415 (1922) (adopting that approach for regulatory takings). Where the Fourth Amendment applies, it applies—regardless of “the quality or quantity of information” the government obtains. Kyllo, 533 U. S., at 37. So, for example, this Court held that thermal imaging qualified as a search even though it did not, and was not likely to, detect “private activities” or “intimate details.” Ibid. The Amendment, we analogized, makes “no exception” for the officer “who barely cracks open the front door and sees nothing but the nonintimate rug on the vestibule floor.” Ibid. And likewise, the Amendment does not give agents a pass if their wiretap is of limited duration and thus less likely to intrude on private matters. Indeed, in our seminal
That approach makes all the more sense when, as with Location History, officials can select the time-limited set of materials they want from an all-encompassing database. Then, the durational bounds on the data actually acquired do little to address the Fourth Amendment’s concern about “a too permeating police surveillance.” Di Re, 332 U. S., at 595; see supra, at 12. What creates that concern is that the government can access all of a cell-phone user’s movements, in both public and private places—that it possesses a virtual panopticon with which to scrutinize its citizens’ activities. The sweep of the official invasion is not made less because the government, with the benefit of hindsight, can pinpoint exactly which few hours of movements it wants to review. That feature of accessing location data is, indeed, more a practical benefit to the government than a limit on its intrusive powers.9
And contra the Government, Knotts does not support the view that accessing two hours of Location History is not a search. There, police officers put a beeper in a car to help them follow it from Minnesota to Wisconsin. The Court decided that the beeper did not turn the tail into a search, but was explicit in keeping its holding cabined to that rudimentary technology. The defendant had argued that a ruling against him would enable officials to conduct “surveillance
And still another feature of Knotts makes it inapt here: that the surveillance there was confined to public roads. That fact was crucial to the Court’s decision: “A person traveling in an automobile on public thoroughfares has no reasonable expectation of privacy,” Knotts explained, because the car is always “in plain view.” 460 U. S., at 281. By contrast, the movements that Location History reveals are not limited to public streets. Recall what Carpenter observed: A “cell phone faithfully follows its owner beyond public thoroughfares and into private residences, doctor’s offices, [and] political headquarters.” 585 U. S., at 311; see supra, at 15.10 In one of those places—a private residence—this
D
The Government has an additional argument, which in Carpenter was its “primary” one—that the so-called third-party doctrine precludes Chatrie from invoking the Fourth Amendment’s protections. 585 U. S., at 313. (Here too the dissent reiterates the Government’s view. See post, at 11–12, 17 (ALITO, J.).) The idea is that in “authoriz[ing] Google to collect, retain, and use” his location information, Chatrie lost his legitimate expectation of privacy, and therefore his right to complain of a search—regardless whether it was for two hours, two weeks, or two years. Brief for United States 15. The problem for the Government—and presumably the reason that its primary assertion in Carpenter has here become a secondary one—is that Carpenter refused to apply the third-party doctrine to CSLI, and no good reason exists to reach a different result for Location History.
The third-party doctrine traces to two cases involving information provided by customers to a bank and telephone company, and then turned over to law enforcement officials. In United States v. Miller, 425 U. S. 435 (1976), this Court held that a bank depositor had no reasonable expectation of privacy in canceled checks and deposit slips in his bank’s possession, because the records were “voluntarily conveyed to the bank[] and exposed to [its] employees in the ordinary course of business.” Id., at 442. The depositor, the Court explained, had “take[n] the risk, in revealing his affairs to another,” that the third party would in turn provide that information to the government. Id., at 443. A few years later, the Court in Smith v. Maryland, 442 U. S. 735 (1979), applied that principle to hold that a (landline) telephone subscriber lacked a legitimate expectation of privacy in the phone numbers he dialed. Once again, the Court reasoned that the subscriber had “voluntarily conveyed [the dialed numbers] to the telephone company,” and so relinquished his Fourth Amendment right. Id., at 744.
Both differentiating features highlighted in Carpenter apply equally or better to Location History. As noted above, Location History is even more “revealing” than CSLI, because it provides a yet more precise record of an individual’s movements. See supra, at 16–17. Access to that record enables officials to undertake nearly perfect, retrospective surveillance of countless persons and places. See supra, at 17–18. And for Location History, that surveillance is based on information that a user reasonably understands as his own, even though stored on Google’s servers—much like his emails, photos, and calendar entries. See supra, at 18. Likewise, the information is “not truly shared,” in the
The Government contests that conclusion on Carpenter’s second axis alone: It claims that generating Location History, unlike producing CSLI, is a voluntary choice on the user’s part. Although carrying a cell phone may be indispensable in modern society, the Government argues, using Location History is not. Rather, Location History is an “optional add-on,” which a user must enable by an “affirmative act” beyond “powering up” a phone. Brief for United States 13, 22 (quoting Carpenter, 585 U. S., at 315). In support, the Government emphasizes that only around one-third of current Google accountholders have activated the service. See Brief for United States 22; see 1 App. 45. That goes to show, says the Government, that people can “live[] without” Location History. Brief for United States 22; see Tr. of Oral Arg. 92. And if that is true (the Government says), people who do use the feature have indeed “voluntar[il]y expos[ed]” all of their movements. Carpenter, 585 U. S., at 315.
But as an initial matter, that argument ignores some pertinent facts about how and why Google users turn on Location History. As described earlier, Google prompts a user, and repeatedly, to turn on the service—when he sets up a Google account, when he sets up an Android phone, and when he sets up a Google app. See supra, at 3–4. The prompt often informs him that his device will not “work correctly” unless he does so. 2 App. 140–141. By contrast, it does not tell him quite what he is signing up for: “how frequently Google would record [his] location“; “how precise
More generally, the Government’s approach to Fourth Amendment protection would raise a host of workability issues. At the top of the list: What percentage of users would have to sign up for a service to make doing so non-voluntary? The Government posited at argument that if 80 percent of active Google accountholders had enabled Location History, the case would be “much closer.” Tr. of Oral. Arg. 92. After all, the Government candidly noted, even possessing a cell phone is not truly “indispensable” (to use Carpenter’s word): “[S]omething like 90 percent of people have [them].” Tr. of Oral. Arg. 92. So where to draw the line? And after that, the questions only multiply. Would a user lose Fourth Amendment protection if a highly popular cell phone feature became less so over time? What if the use of a given feature is ubiquitous among (but only among) a subset of the population (say, an age cohort), and an individual defendant is a member of that class? Would it be enough if
And there is yet a deeper problem: The Government’s app-by-app, feature-by-feature method of granting Fourth Amendment protection misapprehends the very nature of modern cell-phone use. Pretty much everything a person does on a smartphone requires some kind of opt-in—an “affirmative act” beyond “powering up” to utilize a given app or service. Carpenter, 585 U. S., at 315. Consider sending an email on Gmail, uploading a photo to Google Photos, or adding a calendar entry to Google Calendar. None happens solely by dint of the phone’s operation; each requires, as Location History does, an “optional add-on.” Brief for United States 13. And each activity, like using Location History, results in sharing information with a third-party tech company—turning over private materials to live on that company’s servers. The Government wishes to disconnect all those uses from the mere act of carrying a turned-on cell phone (the thing that generates CSLI), with only the latter receiving assured Fourth Amendment protection. But that is to imagine that all of us are living in dumb flip-phone days. The point of carrying smartphones is to use what is on them—as Carpenter said, to use the apps and “services they provide.” 585 U. S., at 315. That is what has become a “pervasive and insistent“—even “indispensable“—“part of daily life.” Ibid.; Riley, 573 U. S., at 385. And so that is what Carpenter insulated from the third-party doctrine. A cell-phone user is not to be viewed as sharing private
* * *
For all those reasons, we hold that police officers invade a cell-phone user’s reasonable expectation of privacy when they access his Location History. It does not matter if the time period scrutinized was only two hours. Nor does it matter that the materials obtained were handed over by a third-party tech company. When the government “accesses historical cell phone” location information—Location History as much as CSLI—it “conducts a search under the Fourth Amendment.” Carpenter, 585 U. S., at 300.
III
That conclusion does not resolve this case, because the Fourth Amendment prohibits only searches that are “unreasonable.” When law enforcement officials undertake a search to discover evidence of a crime, the reasonableness standard generally requires that they seek a warrant from “a neutral and detached magistrate.” Johnson v. United States, 333 U. S. 10, 14 (1948); see Vernonia School Dist. 47J v. Acton, 515 U. S. 646, 653 (1995).11 That requirement subjects the officials’ assessment of a search’s propriety to the “deliberate, impartial judgment of a judicial officer.” United States v. Grubbs, 547 U. S. 90, 99 (2006). The magistrate, in turn, may issue a warrant only when “probable cause is properly established and the scope of the authorized search is set out with particularity.” Kentucky v. King, 563 U. S. 452, 459 (2011).
The warrant issued here, as described earlier, was an uncommon, multi-step one. See supra, at 7–8. The first step it laid out authorized police officers to obtain location data for all cell phones inside the designated geofence within a one-hour timeframe. The second step entitled the officers
The parties have contested the legality of each stage of that process. Chatrie analogizes the first step to an “unconstitutional general warrant,” and argues that in any event the search at that step was both insufficiently described by the warrant and lacking in probable cause. Brief for Chatrie 12; see 2 App. 13. As to steps two and three, Chatrie contends that the warrant left too much authority to police officers—and too little to the magistrate—to define the search’s scope and determine whether cause for it existed. See id., at 13–14. The Government, for its part, defends the warrant at every step as seeking “particularized information from Google’s database” based on “probable cause to believe that Google had information” that would help solve a crime. Brief for United States 14. And the Government urges that the discretion given to the officers at steps two and three fell within the bounds of reasonableness. See id., at 46.
We leave all of those questions to the Court of Appeals to decide in the first instance. Because the Fourth Circuit panel concluded that no search had occurred, it did not address whether the geofence warrant issued here validly authorized each stage of the search process. Nor did the en banc court’s one-sentence per curiam opinion speak to that
IV
In his famed and vindicated dissent, Justice Brandeis explained why a wiretap was a search, subject to Fourth Amendment requirements. See Olmstead v. United States, 277 U. S. 438, 471 (1928). Those who drafted the Amendment could not have imagined such a technology. But they understood, Justice Brandeis wrote, a matter of more transcendent importance: that Americans had “as against the Government, the right to be let alone” and that the Fourth Amendment must protect against “every unjustifiable intrusion by the Government upon the privacy of the individual, whatever the means employed.” Id., at 478.
Far more recently, this Court in Carpenter invoked Justice Brandeis’s opinion in explaining why law enforcement officials could not have “unrestricted access to a wireless carrier’s database of physical location information.” 585 U. S., at 320. Said Carpenter: “[T]he 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.” Ibid. (quoting 277 U. S., at 473–474 (dissenting opinion)). For new technological tools, the Court continued, may “risk[] Government encroachment of the sort the Framers, after consulting the lessons of history, drafted the Fourth Amendment to prevent.” 585 U. S., at 320.
Today’s decision follows from the same judicial obligation, to guard against the same risk of undue encroachment. The Fourth Amendment applies, too, when officials tap into Google’s “database of physical location
For the reasons stated, we vacate the judgment of the Court of Appeals and remand the case for further proceedings consistent with this opinion.
It is so ordered.
I agree with the Court that law enforcement officers conducted a search when they accessed petitioner Chatrie’s Location History. I write separately because I would have gone further to explain that this search violated the Fourth Amendment. As the Court observes, “[w]hen officers have obtained a warrant,” the validity of a search turns on “whether a magistrate has properly found probable cause to support a particularly described search.” Ante, at 30. In my view, it is clear that at a minimum the second and third stages of the search process here did not satisfy this foundational requirement.
At step two, the warrant authorized officers to access an additional hour’s worth of Location History, unbounded by the geofence’s perimeter. Though the warrant stated that officers would “attempt to narrow down the list” of devices subject to this step, there was no explicit requirement that they do so. 2 App. 136 (emphasis added). Nor did the warrant set forth any criteria that officers would use in their narrowing efforts. Ibid.
The same infirmities carried over to step three. At this step, the warrant authorized officers to access “identifying account information,” including the username, date of birth, account number, and any email addresses or
This “uncommon, multi-step” process, ante, at 30, meant that officers conducted key portions of the search outside the supervision of “a neutral and detached magistrate,” Johnson v. United States, 333 U. S. 10, 14 (1948). Put differently, officers could obtain additional, sensitive information at steps two and three without having to convince a magistrate that there was probable cause to believe this particular information would uncover evidence related to the crime. In this way, the warrant left “too much to the discretion of the officer[s] executing the order,” giving them a “roving commission” to collect more data absent any justification to a magistrate. Berger v. New York, 388 U. S. 41, 59 (1967).
The facts of this case illustrate why the lack of magisterial oversight is dangerous. When executing steps two and three, law enforcement initially sought unbounded data and account information from all 19 devices identified at step one. See 590 F. Supp. 3d 901, 921 (ED Va. 2022). Nothing in the warrant prevented officers from obtaining this broad set of data; they narrowed the list only because Google insisted on it. The officers eventually settled on requesting data from nine devices at step two, but even this shorter list may have been overbroad. For three of the nine devices, the location data showed the users’ movements to and from sensitive spaces—namely, residences, a school, and a hospital. See id., at 923. Given how it was written, the warrant itself provided no “judicial check” on law enforcement’s determination that probable cause justified this intrusion. Steagald v. United States, 451 U. S. 204, 220 (1981).
* * *
The Court correctly observes that allowing the Government to “access all of a cell-phone user‘s movements” without limit essentially arms it with “a virtual panopticon with which to scrutinize its citizens’ activities.” Ante, at 21. It is for this reason that law enforcement and courts must carefully abide by the
I agree with the Court‘s judgment that the government‘s examination of Okello Chatrie‘s Location History data amounted to a search for purposes of the
I
To decide whether a
If Katz has become a familiar feature of our law, it seems to me no more persuasive for it. Consider just a few of its problems, beginning with this: It has no basis in the Constitution‘s text or history. The
Even if I could overlook that problem with Katz, I still wouldn‘t know how to apply it. As the Court has candidly admitted, it has never been able to identify a “single rubric” that might “definitively resolv[e] which expectations of privacy are entitled to protection.” Carpenter, 585 U. S., at 304 (majority opinion). Maybe Katz poses an empirical question, tagging reasonable expectations of privacy to those privacy expectations “people actually have.” Carpenter, 585 U. S., at 392 (GORSUCH, J., dissenting). Or maybe the question is a normative one, asking what expectations reasonable people ”should . . . have.” Ibid. In truth, nobody knows and, either way, this Court is the wrong body for the task. We aren‘t equipped to make empirical assessments about what most Americans think. Nor is it our job to enforce our own normative judgments, as opposed to those embodied in the Constitution and laws. Id., at 392–394.
If this weren‘t trouble enough, we‘ve also adorned Katz with an equally indefensible qualification called the third party doctrine. Under its terms, the Court has held, an individual maintains no “reasonable expectation of privacy” in information he shares with others. Accordingly, the government may freely search a person‘s papers and effects without triggering any
Much as with Katz itself, this Court has never offered a persuasive justification for its offshoot. Carpenter, 585 U. S., at 389–390 (GORSUCH, J., dissenting). Nor do I see how it might. Do we seriously mean to suggest that most
As it did eight years ago in Carpenter, the Court today largely ignores these problems. It simply declares that Mr. Chatrie enjoyed a reasonable expectation of privacy in his Location History because authorities could have used it to create “a virtual panopticon.” Ante, at 21. And it tells us that the third party doctrine does not apply to this case because Mr. Chatrie did “‘not truly shar[e]‘” his Location History with Google. Ante, at 25–26 (quoting Carpenter, 585 U. S., at 315 (majority opinion)).
Count me unpersuaded. Why does tracking Mr. Chatrie‘s movements digitally over an hour or two invade his reasonable expectation of privacy when an officer tailing him for the same length of time would not? See United States v. Knotts, 460 U. S. 276, 281–283 (1983). Why is Location History data Mr. Chatrie voluntarily shared with Google not “truly shared” when a person‘s bank records are? See Miller, 425 U. S., at 440–443. Does the Court just mean to give Katz‘s third party doctrine a quiet burial by suggesting today that any information shared over “smartphones” using “apps and services” falls outside its reach? Ante, at 28 (internal quotation marks omitted). And what does any of this have to do with the
II
Rather than employ Katz and its third party doctrine, I would take a different approach. To decide whether the
Thanks to Katz‘s prominence today, of course, litigants sometimes fail to press more traditional
I agree with that assessment. Set aside whether Location History data qualifies as among Mr. Chatrie‘s “papers,” and consider whether it at least constitutes one of his “effects.” Based on the evidence the parties have put before us, it appears the word “effects” was understood at the time of the
As I see it, Mr. Chatrie‘s Location History data qualifies as his personal property. To appreciate why, start with this. As Google puts it, and no one seriously disputes, Location History serves as a “diary” or map “of a person‘s travels.” Brief for Google LLC as Amicus Curiae 3–4. At the time of the events in question, Mr. Chatrie‘s agreement with Google referred to Location History as “your” (meaning, the user‘s) “information.” 1 App. 72 (emphasis added). Under the parties’ agreement, too, Mr. Chatrie was free to “review” and “edit” his location data. Id., at 19. He was even free to export or delete that data “from Google‘s servers at will.” Ibid. Beyond all that, Google promised to protect his information against “unauthorized access, alteration, disclosure, or destruction.” Id., at 71. Put simply, Mr. Chatrie had the rights to enjoy, manage, alter, dispose, and exclude others from what amounted to an electronic diary or map of his travels. And as someone who held that many “sticks in the bundle of rights . . . commonly characterized as property“—including the “most treasured” and “essential” right to exclude—he has a strong claim that the Location History data was his personal property. Cedar Point Nursery v. Hassid, 594 U. S. 139, 149–150 (2021) (internal quotation marks omitted).
Next, notice what statutory and case law have to say on the subject. The investigation of Mr. Chatrie unfolded in Virginia. That State‘s Computer Crimes Act expressly describes “computer data” as a form of “[p]roperty.”
Nor is Virginia some outlier. In Texas, “computer . . . data” can constitute “[p]roperty.”
To be sure, pursuant to its agreement with Mr. Chatrie,
Nor does it matter that those who wrote the
Because Mr. Chatrie‘s Location History data is his effect, it is subject to the
*
I might have hoped that the Court would have pursued a more traditional approach to the
Eight years ago, I warned that this Court‘s decision in Carpenter v. United States, 585 U. S. 296 (2018), would produce one of two outcomes. Either the Court would need to clarify Carpenter‘s limits in a future decision, or Carpenter would usher in “revolutionary developments” in our doctrine by giving criminal suspects a “protected Fourth Amendment interest in any sensitive personal information about them that is collected and owned by third parties.” Id., at 385 (ALITO, J., dissenting). Today, the Court takes the country down the latter path. In doing so, the Court sheds Carpenter‘s self-imposed boundaries and further destabilizes longstanding
To make matters worse, the majority does all this in an advisory opinion. Although today‘s decision will send seismic waves through our
I
The Court should not have granted certiorari in this case, and under any faithful application of our precedents, it should now either dismiss this petition or affirm the decision below based on the “good-faith exception” to the exclusionary rule. Instead, the Court issues an advisory opinion concerning a now-obsolete “geofence” procedure. Last Term, the Court worried out loud about rushing in to judge “new technologies with transformative capabilities” that we barely understand. TikTok Inc. v. Garland, 604 U. S. 56, 62 (2025) (per curiam). In cases involving such technology, the Court proclaimed, we should take care not to “‘embarrass the future.‘” Ibid. (quoting Northwest Airlines, Inc. v. Minnesota, 322 U. S. 292, 300 (1944)). Today, the Court exhibits no such modesty.
A
It has long been established that federal courts may not issue “advisory opinions” that do not bear on the rights of the litigants before them. Lewis v. Continental Bank Corp., 494 U. S. 472, 477 (1990). At the appellate stage, this principle means that courts should resolve only those questions on which a favorable ruling would provide a litigant redress from the judgment below. See Food Marketing Institute v. Argus Leader Media, 588 U. S. 427, 432–433 (2019). The question on which the Court granted certiorari in this case cannot satisfy this requirement under any colorable view of the law. The Court should therefore decline to answer it.
Okello Chatrie‘s ongoing stake in this case stems from his conviction for robbing a bank and brandishing a firearm. On appeal, Chatrie challenged those convictions on only one ground. He argued that the District Court erred in denying his motion to suppress the fruits of the geofence procedure
The police obtained information about Chatrie‘s location at the time of the robbery pursuant to a warrant issued by a neutral magistrate. And when evidence is obtained under such a warrant, a defendant seeking suppression must overcome the good-faith exception to the exclusionary rule. United States v. Leon, 468 U. S. 897, 923 (1984). A majority of the Court of Appeals for the Fourth Circuit, sitting en banc, held that Chatrie could not do so. 136 F. 4th 100, 101 (2025) (Diaz, C. J., concurring); id., at 114 (Niemeyer, J., concurring); id., at 115 (King, J., concurring); id., at 115, n. 1 (Winn, J., concurring in judgment); id., at 142 (Heytens, J., concurring). That holding suffices to affirm the District Court‘s admission of the geofence evidence and thus independently supports the Fourth Circuit‘s judgment. Accordingly, any review by this Court should concern an issue that could at least plausibly disturb that good-faith holding. Cf. Stewart v. IHT Ins. Agcy. Group, LLC, 990 F. 3d 455, 457 (CA6 2021).
On this score, today‘s decision fails. The majority does not dispute the Fourth Circuit‘s good-faith analysis, and nothing in its opinion casts a shred of doubt on that holding. See ante, at 10, n. 4. To overcome the good-faith exception, Chatrie would need to show that either (1) the affidavit supporting the geofence warrant was knowingly or recklessly
This outcome was guaranteed as soon as this Court granted certiorari. When seeking review in this Court, Chatrie recognized that dislodging the Fourth Circuit‘s judgment required that he prevail on the good-faith issue, so his petition asked us to alter the good-faith exception. See Pet. for Cert. i, 34–37 (asking the Court to create a carve-out to the good-faith exception). Yet the Court excluded the good-faith issue from its grant of certiorari, 607 U. S. 1148 (2026), ensuring that any opinion would be advisory. Indeed, even if the Court were to decide that the
The Court therefore erred by granting certiorari, and we should now dismiss this petition as improvidently granted. See Conway v. California Adult Authority, 396 U. S. 107, 110 (1969) (per curiam) (dismissing when resolving the issue addressed in the petition would produce an advisory opinion). Alternatively, this Court could affirm the decision below on good-faith grounds. Although the Court did not grant certiorari on this question, we may affirm a judgment on any ground supported by the record, and we would not be the court of “first view” on the good-faith issue. Upper Skagit Tribe v. Lundgren, 584 U. S. 554, 560–561 (2018). The Government properly presented this issue below, the District Court admitted the contested evidence on good-faith grounds, a majority of the en banc Fourth Circuit voted to affirm on that basis, and the Government continued to press good faith at the petition and merits stages in this Court. See Government‘s Response in Opposition to Defendant‘s Motion for Suppression, ECF Doc. 41, p. 21; 590 F. Supp. 3d 901, 937 (ED Va. 2022); Brief in Opposition
Instead, the Court charges forward to decide the question presented, even though the majority cannot discern any impact that its decision has on the Fourth Circuit‘s judgment. See ante, at 10, n. 4. The majority thus issues a plainly advisory opinion, violating this Court‘s “oldest and most consistent” justiciability rule. Flast v. Cohen, 392 U. S. 83, 96 (1968) (internal quotation marks omitted).
B
Advisory-opinion concerns aside, our prudential certiorari considerations further counseled against granting certiorari. Writs of certiorari are discretionary, and we reserve them for “compelling” cases in which the court below “has decided an important question of federal law.” This Court‘s Rule 10. The question in this case does not qualify.
Chatrie‘s petition asked whether the geofence procedure that the police used here comports with the
This Court has long been averse to granting certiorari on questions “that time [will] soon bury.” Darr v. Burford, 339 U. S. 200, 227 (1950) (Frankfurter, J., dissenting). This aversion applies with special force here given this case‘s subject matter. The
None of this is to say that today‘s decision will be inconsequential. As the majority works its way through the question in this case, it makes sweeping proclamations with implications far beyond the specific procedure that the police used here. But this fact only underscores the advisory nature of today‘s decision. The majority has candidly little to say about the relevance of its decision for Chatrie‘s conviction. Ante, at 10, n. 4. Instead, the Court uses this case as a vehicle to once again “make a statement about privacy in the digital age.” See Carpenter, 585 U. S., at 386 (ALITO, J., dissenting). Because that function is not a proper use of this Court‘s certiorari docket, we should not have granted this petition and should now dismiss it.
II
The Court‘s resolution of the merits of this case is equally flawed. Applying the
A
If the Court were to apply the
To illustrate this point, imagine that Chatrie spent his free time taking road trips across the United States. And suppose that he entered into a contract with a travel agency, under which the agency would provide him valuable information about places to visit and activities to try as he traveled from place to place. Suppose that the contract, in exchange for these services, authorized the travel agency to maintain a detailed chronicle of Chatrie‘s adventures and to use that information to develop its business, expand its offerings, and advertise to prospective customers. If a grand jury had subpoenaed the travel agency for the records of Chatrie‘s travels, he would have no basis to object on search-and-seizure grounds. At least through the late 19th century, compelled document-production orders were simply not “searches.”
In short, under traditional search-and-seizure principles, Chatrie could not challenge the geofence procedure here under the
B
1
In the 20th century, this Court expanded its
Whatever one thinks of Katz‘s expansion of
does not protect privacy interests in household garbage left curbside); California v. Ciraolo, 476 U. S. 207, 213–215 (1986) (holding that Katz does not require a warrant for aerial surveillance).
Similarly, even after Katz, the Court recognized that legislatures still bore primary responsibility for regulating the use of new technologies and investigation methods. Thus, when legislatures developed reasonable schemes to administer such activities, the Court was reluctant to constitutionalize additional rules. See, e.g., Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523, 534–539 (1967) (upholding the constitutionality of a search conducted pursuant to “reasonable legislative or administrative standards“); King, 569 U. S., at 465 (holding that a DNA collection scheme was constitutional in part because state statute regulated how records could be used); see also Burger, 482 U. S., at 707–711 (allowing warrantless inspections pursuant to a regulatory scheme designed to combat modern problems with car theft). As much as Katz reflected a departure from traditional Fourth Amendment rules, this Court‘s decisions made clear that it was a measured one.3
2
The geofence procedure in this case did not violate Chatrie‘s Fourth Amendment rights under these 20th-century precedents. These precedents hold that a defendant does not have a reasonable expectation of privacy in records that a company generates by virtue of the defendant‘s use of its services. This rule has come to be known as the third-party doctrine. The Court articulated this rule in United States v. Miller, 425 U. S. 435 (1976), holding that the police did not violate a defendant‘s Fourth Amendment rights when
What was true about the bank records in Miller is true about Location History here. Chatrie voluntarily conveyed his location information to Google, and Google created a digital paper trail of that information. Like the bank in Miller, Google was no neutral custodian in this arrangement. Id., at 440. In exchange for allowing Chatrie to use its Location History service, Google could use his location information for its own business purposes, such as sending Chatrie location-targeted advertisements from third parties. 590 F. Supp. 3d, at 907–908. So, by giving Google his location information for its own use, Chatrie assumed the risk that Google might disclose location information to others, including the police. Miller, 425 U. S., at 443. Indeed, Google advises its users that the company could use their location information for its own advertising purposes and could share that information with law enforcement. E.g., 1 App. 69–70. Thus, like the defendant in Miller, Chatrie cannot now claim a reasonable expectation of privacy in those data. The police therefore would not need a warrant to perform the geofence procedure under our 20th-century precedents.
C
1
Without any support in 19th- or 20th-century understandings of the Fourth Amendment, Chatrie and the majority rely primarily on this Court‘s decision in Carpenter. Carpenter held that the police must obtain a warrant before ordering a cellular carrier to provide more than six days of cell-site records about a customer (i.e., information about the specific cell towers to which a cell phone connected). 585 U. S., at 315–316. Like Katz, Carpenter extended the Fourth Amendment‘s warrant requirement to encompass a category of government investigations that it had never previously covered. Before Carpenter, a criminal defendant who objected to police collection of cell-site records would have faced at least two legal hurdles: the historical distinctions between searches and subpoenas duces tecum, and the third-party doctrine. Carpenter, 585 U. S., at 361–362 (ALITO, J., dissenting). Carpenter thus reflected a “stark departure” from both traditional Fourth Amendment principles and this Court‘s 20th-century doctrine. Id., at 321 (Kennedy, J., dissenting).
Nonetheless, Carpenter maintained that its departure from these doctrines was “narrow.” Id., at 316 (majority opinion). The question presented in Carpenter was whether the Fourth Amendment allows “the warrantless seizure and search of historical cell phone records revealing the location and movements of a cell phone user over the course of 127 days,” Pet. for. Cert. in Carpenter v. United States, O. T. 2017, No. 16–402, p. i, and the Court purported to resolve no more than the question before it, 585 U. S., at 316, and n. 4. Carpenter‘s analysis likewise anchored itself in the “unique nature” of the particular cell-site records that the police had collected in that case. Id., at 315. In “declin[ing] to extend” the third-party doctrine to weeks-long cell-site records, Carpenter highlighted various aspects of that dataset that, in the majority‘s view, afforded the
Three of those aspects—duration, comprehensiveness, and voluntariness—deserve mention here. First, unlike traditional police-surveillance techniques, the dataset in Carpenter captured the “whole of [a person‘s] physical movements” over 127 days, violating Americans’ reasonable expectation that they would not be “secretly monitor[ed]” for a “very long period.” Id., at 310 (internal quotation marks omitted). Second, the dataset gave the police an “all-encompassing record” of the defendant‘s whereabouts that tracked him “beyond public thoroughfares and into private residences . . . and other potentially revealing locales.” Id., at 311. Third, the Court determined that cell-phone users do not “voluntarily” share their cell-site information with cellular carriers in the same way that the defendant in Miller voluntarily conveyed his transaction information to a bank. Carpenter, 585 U. S., at 315. The Court reasoned that because cell phones are “indispensable to participation in modern society” and “[v]irtually any activity on [a] phone” generates cell-site records, a person has no practical choice but to constantly convey this information to third parties. Ibid. Based on these aspects of the dataset at issue, Carpenter concluded that the defendant had a strong enough privacy expectation that the rationale undergirding our third-party case law did not apply. Id., at 314–315. Carpenter therefore held that the police needed a warrant to obtain seven or more days of cell-site records from a cellular carrier. Id., at 310, n. 3, 316.
2
Carpenter did not require the police to obtain a warrant for the geofence procedure here. By its own terms, Carpenter‘s holding was keyed to the “unique nature” of the cell-site records in that case. Id., at 309, 315. Carpenter expressly left open the question whether the police would
Nor does Carpenter‘s reasoning justify extending its holding to this case. Here, the police requested two pieces of information that could implicate Chatrie‘s Fourth Amendment interests: (1) whether he was within 150 meters of the credit union during the robbery, and (2) if he was, where he traveled during the 1-hour periods immediately before and afterward. Along three of the dimensions that Carpenter found relevant, Chatrie has a far lesser privacy interest in this information than the defendant did in the records at issue in that case. The third-party doctrine therefore controls.
First, unlike the data collection in Carpenter, the geofence procedure in this case did not risk uncovering the “whole of [someone‘s] physical movements.” 585 U. S., at 310. In contrast to the 127 days of cell-site records in Carpenter, the request made by the police here spanned just two hours.4 Until today, this Court had recognized a Fourth Amendment difference between tracking a person‘s movements for a “brief stretch” and cataloging them for an “‘extended period of time.‘” Ibid.; Jones, 565 U. S., at 430 (opinion of ALITO, J.). Although it might be difficult to “identify with precision” the dividing line between these two durations, a 2-hour stint of location tracking is “surely” too limited to constitute the “all-encompassing record” that
Second, the limited geofence procedure here was far less likely to open “an intimate window” into Chatrie‘s “‘familial, political, professional, religious, and sexual associations‘” than was the chronicle that the police obtained in Carpenter. Id., at 311. Whereas the procedure in Carpenter gave the police a comprehensive log of the defendant‘s movement everywhere he went, the geofence‘s boundaries here centered on a credit union,5 a public place where individuals lack a reasonable expectation of privacy.6 Cf. Miller, 425 U. S., at 442–443 (holding that a person has no expectation of privacy in his dealings with a bank); Knotts, 460 U. S., at 281–282 (holding that a person has no expectation of privacy in his travels through public places). To be sure, the geofence procedure also captured some people‘s movements outside the geofence in the hour before and after they visited the credit union, and it is feasible that some people might have traveled to a private location during that window. But the incidental acquisition of such information through otherwise-permissible surveillance does not violate Chatrie‘s Fourth Amendment rights. Id., at 282 (holding that no search of the defendant occurred when a police
Third, unlike the generation of cell-site records, the creation of Location History data is voluntary and not integral to a cell phone‘s functionality. Cell-site records are the byproduct of every phone interaction with a cell tower and thus an unavoidable consequence of sending text messages, making phone calls, or connecting to the internet. Carpenter, 585 U. S., at 315. A person can avoid creating those records only by forgoing all use of a cell phone for these purposes, and doing so would render useless this “indispensable” component of modern life. Ibid. In contrast, users need not enable Location History for their phones to function as expected. That most Google accountholders carry on without using Location History is strong evidence that the service is not a “pervasive and insistent part of daily life” in the way that creating cell-site records is. Ibid. (internal quotation marks omitted); see ante, at 26.
Thus, on the criteria that Carpenter found relevant in determining whether to apply the third-party doctrine, Chatrie has a far lesser privacy interest in the data that the police sought here. For that reason, I would not extend Carpenter here, and I would hold that the police did not need a warrant.
3
The majority reaches the opposite outcome, and in doing so, it announces a new rule of Fourth Amendment law: The police must obtain a warrant every time they access any cell-phone location information from a third party, however brief the duration, however innocuous the request, and however voluntarily that information was disclosed by the user. Ante, at 29. This rule significantly extends Carpenter and repudiates the boundary lines that Carpenter drew to distinguish its novel holding from longstanding doctrine. Whereas Carpenter rested its holding on the difference between obtaining a “brief stretch” of location information and receiving a chronicle spanning a week or more, 585 U. S., at 310, 315, the majority holds that the police need a warrant regardless of the duration of the data sought, ante, at 18–23. Whereas Carpenter rested its holding on the concern that an all-encompassing dataset would reveal a defendant‘s presence in sensitive locations, 585 U. S., at 311, the majority holds that the police need a warrant regardless of whether a geofence captures any sensitive locations, ante, at 22–24. Whereas Carpenter rested its holding on the near-universal use of cellphones and the unavoidability of generating cell-site records, 585 U. S., at 315, the majority holds that the police need a warrant regardless of how widespread a technology is or how feasibly users may opt out, ante, at 26–29. Now, we are told, all that matters is whether a given investigative procedure enables the police to obtain location information easily using a technology that did not exist in “an earlier age.” Ante, at 16–18. If so, the police need a warrant.
This unshackling of Carpenter will unleash the very upheaval in Fourth Amendment law that Carpenter disclaimed. See 585 U. S., at 319 (stating that its holding would apply “only . . . in the rare case“). Today‘s decision makes clear that the last two centuries of Fourth Amendment search doctrine simply do not apply to digital-age
4
In support of its sweeping conclusion, the majority argues that a duration-based or procedure-by-procedure approach to the Fourth Amendment would generate a “host of line-drawing questions.” Ante, at 21, n. 9; see also ante, at 27–28. I do not disagree, but those questions are the inevitable byproduct of the lines that Carpenter drew when it distinguished away longstanding doctrine. See 585 U. S., at 322, 339 (Kennedy, J., dissenting) (explaining that Carpenter drew an “unprincipled and unworkable line” and imposed an “arbitrary 6-day cutoff“). Indeed, the majority‘s rejection of such line-drawing only betrays its expansion of Carpenter‘s holding.
In any event, the majority‘s approach creates its own share of line-drawing problems. What dividing line can explain why a defendant has a reasonable expectation of privacy in his cell-phone location information but not in his bank records? See Miller, 425 U. S., at 442–443. Debit and credit cards might be viewed as comparably “indispensable to participation in modern society,” and their use creates a detailed paper trail. Carpenter, 585 U. S., at 315. As a result, modern bank records contain similarly comprehensive accounts of Americans’ private lives, including “the political and religious organizations to which they donate; whether they have visited a psychiatrist, plastic surgeon, abortion clinic, or AIDS treatment center; [and] whether they go to gay bars or straight ones.” Id., at 337 (Kennedy, J.,
More broadly, where does the boundary between Carpenter and the third-party doctrine lie after today? Carpenter gave “courts and law enforcement officers no indication how to determine whether any particular category of information falls” on the Carpenter or Miller side of the line, and today‘s decision does no better. Carpenter, 585 U. S., at 340 (Kennedy, J., dissenting). Do the police need a warrant to obtain a person‘s Amazon purchase history? What about a person‘s Google search history or Venmo transaction log? Those kinds of information fall squarely within the third-party doctrine, and today‘s holding about “cell phone location information” does not ostensibly disturb that fact. Ante, at 29 (internal quotation marks omitted). At the same time, those data can paint a similarly detailed picture of a person‘s private life, and law enforcement had no easy way to obtain this information in “an earlier age.”8 Ante, at 17. If the Court maintains its unwillingness to engage with such “line-drawing questions,” ante, at 21, n. 9, Carpenter‘s warrant requirement might soon come for all forms of digital surveillance.
* * *
In Carpenter, I worried that we might be “picking up the pieces” of our Fourth Amendment doctrine for a long time to come. 585 U. S., at 362 (dissenting opinion). Today‘s
I have no quarrel with Carpenter v. United States, 585 U. S. 296 (2018), or with the Court‘s decision to grant certiorari in this case. But I agree with JUSTICE ALITO that under our Fourth Amendment precedent, including Carpenter, Chatrie had no reasonable expectation of privacy in data about his public movements that he voluntarily disclosed to Google. I therefore respectfully dissent.