Chatrie v. United States

(Slip Opinion) OCTOBER TERM, 2025 1 Syllabus 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 CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FOURTH CIRCUIT No. 25–112. Argued April 27, 2026—Decided June 29, 2026 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 de- scribed 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 fi- nal list. The magistrate issued the warrant, and through this process, Google ultimately produced three cell-phone users’ identifying infor- mation, including petitioner Okello Chatrie, whose location data showed that he entered the geofence about ten minutes before the rob- bery and headed toward a residential area immediately after leaving 2 CHATRIE v. UNITED STATES Syllabus the bank. 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 inva- lid. The District Court found that the geofence warrant “plainly vio- lates 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 be- cause 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 vio- lated 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 infor- mation. Pp. 10–33. (a) The Fourth Amendment protects individuals’ reasonable expec- tations 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 ob- stacles 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 fol- lows” him not only through “public thoroughfares [but] into private residences, doctor’s offices, political headquarters, and other poten- tially 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  Cite as: 609 U. S. ___ (2026) 3 Syllabus in time,” making possible a form of surveillance that would have been unknown prior to the digital age, id., at 311–312. Carpenter accord- ingly held that “[a]llowing government access to cell-site records con- travenes” expectations of privacy. Id., at 311. Pp. 13–15. (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 Loca- tion 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 His- tory 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 im- plicates personal privacy interests even more than CSLI, because Lo- cation 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 pri- vate 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 gov- ernment. 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,” Pennsyl- vania 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 Loca- tion 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 4 CHATRIE v. UNITED STATES Syllabus 15. But Carpenter refused to apply the third-party doctrine to CSLI, and no good reason exists to reach a different result for Location His- tory. In Carpenter, the Court rejected application of the third-party doctrine to CSLI because such information is “qualitatively different” from “telephone numbers and bank records,” 585 U. S., at 309—it is incomparably “revealing” and is “not truly ‘shared’ as one normally un- derstands the term” given that cell phones are “indispensable to par- ticipation in modern society,” id., at 315. Both differentiating features apply equally or better to Location History, which is even more “re- vealing” than CSLI and is “not truly shared” in the normal sense of wanting a third party to see or use it. Id., at 315. The exposure of that information to Google is merely what happens when a user avails him- self of one of the services on his cell phone. The Government’s argu- ment that generating Location History, unlike producing CSLI, is a voluntary choice is meritless. That argument ignores how and why Google users turn on Location History: Google repeatedly prompts us- ers to turn on the service, often warning that devices will not “work correctly” otherwise, 2 App. 140–141, while not disclosing in that prompt how frequently users’ location information would be recorded, how precise it would be, or how it might be given to the government. More generally, an app-by-app, feature-by-feature method of granting Fourth Amendment protection misapprehends the nature of modern cell-phone use, where nearly everything requires some kind of “affirm- ative act” beyond “powering up” a given app or service. The Govern- ment wishes to disconnect the activities people do on their cell phones from the mere act of carrying a turned-on cell phone (the thing that generates CSLI), with only the latter receiving assured Fourth Amend- ment protection. But the point of carrying smartphones is to use what is on them—as Carpenter said, to use the apps and “services they pro- vide.” 585 U. S., at 315. Accordingly, a cell-phone user is not to be viewed as sharing private information with third parties—which then can be freely passed on to the government—just by doing the ordinary things cell-phone users do. Pp. 24–29. (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 un- dertake 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 estab- lished and the scope of the authorized search is set out with particu- larity,” Kentucky v. King, 563 U. S. 452, 459. The warrant issued here, as described earlier, was an uncommon, multi-step one, and the par- ties have contested the legality of each stage of the search process it  Cite as: 609 U. S. ___ (2026) 5 Syllabus authorized. The Fourth Circuit did not address the questions that un- usual warrant raises. Because this is “a court of review, not of first view,” Cutter v. Wilkinson, 544 U. S. 709, 718, n. 7, the Court leaves it up to the Court of Appeals to decide whether, at each step of the search process, the warrant satisfied the Fourth Amendment’s requirements of particularity and probable cause. Pp. 29–32. 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 dis- senting opinion.  Cite as: 609 U. S. ____ (2026) 1 Opinion of the Court 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. SUPREME COURT OF THE UNITED STATES _________________ No. 25–112 _________________ OKELLO T. CHATRIE, PETITIONER v. UNITED STATES ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FOURTH CIRCUIT [June 29, 2026] JUSTICE KAGAN delivered the opinion of the Court. In recent years, law enforcement officers have employed so-called geofence warrants to obtain information that tech- nology companies collect about their users’ cell-phone loca- tions. Suppose that investigators know a crime was com- mitted at a particular place and time, but do not have a suspect. They may draw a “geofence”—a virtual perime- ter—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 mil- lions of Google users have activated a service called Loca- tion History, which records the location of a user’s cell phone every two minutes or so. Through a geofence war- rant, 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 2 CHATRIE v. UNITED STATES Opinion of the Court the police three names. The Federal Government soon charged one of the individuals thus identified, petitioner Okello Chatrie, with committing the crime. 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 war- rant 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 constitu- tionally protected interest when they demand the infor- mation—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. To- day, 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  Cite as: 609 U. S. ____ (2026) 3 Opinion of the Court “detailed information about all aspects of a person’s life.” Riley, 573 U. S., at 396. 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 com- bined, the signals tracked can determine a cell phone’s lo- cation 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 His- tory, 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, —————— 1 Throughout this opinion, we describe how Location History worked at the time the warrant at issue was executed. As noted below, Google has since then instituted a significant change, which apparently insulates Location History data from geofence warrants. See infra, at 4, n. 2. 4 CHATRIE v. UNITED STATES Opinion of the Court Google Maps, or Google Photos—on his phone or other de- vice. Android (though not iPhone) users are specifically warned that their devices will not “work correctly” unless they turn on Location History. 2 App. 140–141. And once a user does so, the service runs—and runs constantly—in the background. Regardless whether the user has a Google app open—or whether he is using his phone at all—Loca- tion History remains active. Indeed, it continues to work even if the user deletes the app through which he first turned it on. Location History stops only if a user affirma- tively stops it. Sans that intervention, it tracks and tracks and tracks a user’s cell phone (and other devices). Google stores all Location History data in the cloud, ra- ther 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 —————— 2 Except that in July 2025, years after the geofence warrant used in this case, Google made a change: It now stores Location History data on individual users’ devices rather than on its own servers. See Brief for Google LLC as Amicus Curiae 2. Google represents that, as a result, it is no longer capable of responding to geofence warrants that seek Loca- tion History data. See ibid.  Cite as: 609 U. S. ____ (2026) 5 Opinion of the Court Google creates from it—in the palm of his hand. The user thus can access a “Timeline” showing where he has traveled when; receive real-time updates about his daily commute; and take advantage of maps and recommendations based on his usual movements. 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 war- rant, 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 re- ceived 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_war- rants_united_states.pdf (archived at https://perma.cc/ LN4P-KQJA). Though the details vary, each has made the 6 CHATRIE v. UNITED STATES Opinion of the Court same essential demand: Tell us, through cell-phone location data, who was there when a crime happened.3 As those demands began to proliferate, Google worked with law enforcement officials to develop a three-step pro- tocol 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 sur- rounding a latitude/longitude coordinate—during a speci- fied 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 net- work, 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 re- view the data produced and typically ask Google to provide additional information for a subset of still-anonymized us- ers. 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, offi- cials 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, —————— 3 Google is not the only tech company that has received geofence war- rants; so have Apple, Lyft, Snapchat, and Uber, among others. See 136 F. 4th 100, 102, n. 1 (CA4 2025) (en banc) (Diaz, C. J., concurring). But Google is the “most common recipient and the only one known to re- spond.” Ibid.  Cite as: 609 U. S. ____ (2026) 7 Opinion of the Court threatening to hurt her and her family if she did not com- ply, and warning her that he had “boys on the lookout out side.” 590 F. Supp. 3d, at 905–906. When the teller replied that she did not have access to that amount of money, the robber brandished a firearm. He ordered everyone in the bank to the ground, and forced the bank’s manager to open a safe and put $195,000 into a bag. The robber then left on foot with the money. Local police officers responded to the scene and began an investigation. They learned, from witness interviews and surveillance-camera footage, that the robber had ap- proached 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 identify- ing the robber, his possible accomplices, or additional wit- nesses 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 loca- tion 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 coordi- nates for each [device] and comparing that against the known time and location information that is specific to this 8 CHATRIE v. UNITED STATES Opinion of the Court crime.” 2 App. 136. For that narrowed list, Google would provide additional (but still anonymized) data—cell-phone locations both inside and outside the geofence during a two- hour period (so now from 3:50 to 5:50 p.m.). Finally, at step three, police would again “attempt to narrow down the list by comparing this additional information regarding travel and time against the known time and location information that is specific to this crime.” Id., at 137. And Google would then turn over identifying information for each user on the final list, including his name and phone number. The magistrate issued the warrant, and officers executed it in the manner prescribed. At the first stage of the pro- cess, Google gave up anonymized data for 19 users found within the geofence during the hour within which the rob- bery 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 infor- mation. 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 residen- tial area of town immediately after leaving the bank. Following further police work, a federal grand jury charged Chatrie with robbery and related firearms of- fenses. He moved to suppress the information that the po- lice had obtained from Google. According to Chatrie, the officers had acquired that data through a Fourth Amend- ment 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 particu- lar geofence warrant plainly violates the rights enshrined in [the Fourth] Amendment,” the court stated, the officers’  Cite as: 609 U. S. ____ (2026) 9 Opinion of the Court reliance on it was not “objectively unreasonable.” 590 F. Supp. 3d, at 905, 938. And because that was so, the court concluded, the good-faith exception to the exclusionary rule permitted admission of the location data. See id., at 937– 938; United States v. Leon, 468 U. S. 897, 922–923 (1984) (establishing good-faith exception). A divided panel of the Court of Appeals of the Fourth Cir- cuit 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 volun- tarily 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 trig- gered the Fourth Amendment’s protections,” and that the warrant issued was “so lacking in particularity and proba- ble cause that it was invalid.” Id., at 339, 362, and n. 12. After granting rehearing en banc, the Fourth Circuit af- firmed 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 Amend- ment 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 excep- tion applied, so ruled against Chatrie anyway. We granted certiorari solely on the question whether the police violated the Fourth Amendment in obtaining Cha- trie’s location data, thus declining to consider the exclusion- ary 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 indi- vidual has a legitimate expectation of privacy in his cell- 10 CHATRIE v. UNITED STATES Opinion of the Court phone location data. Second, did the multi-step geofence warrant issued here make that search reasonable? We leave that question—which requires deciding whether the warrant satisfied the Fourth Amendment’s probable cause and particularity requirements at each stage of the search process—to the Court of Appeals to address in the first in- stance.4 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 —————— 4 In line with our grant of certiorari, we do not address whether the good-faith exception to the exclusionary rule still allows the admission of the Location History data in this case. That question remains for the Fourth Circuit to consider anew, gleaning anything it thinks relevant from our decision on the substantive Fourth Amendment issues. The principal dissent seeks to rehash our limited grant of certiorari, but we see no reason to doubt it. We have Article III jurisdiction in this case, as even the dissent concedes. See post, at 4, n. 2 (ALITO, J.). That is because the Fourth Circuit is free to revisit the exclusionary rule issue in light of our opinion and to provide Chatrie with relief. See Chafin v. Chafin, 568 U. S. 165, 172 (2013) (Article III jurisdiction disappears only when it becomes “impossible for the court to grant any effectual relief whatever to the prevailing party”). So what does the dissent mean when it continually labels this opinion “advisory” (post, at 1, 2, 4, 5, 6, 7)—a term customarily used to describe opinions lacking a jurisdictional basis? Apparently, the dissent’s objection is that we today decide a question in- volving the Fourth Amendment when the odds are strong (so says the dissent) that the Fourth Circuit will eventually, as it did before, resolve this case on exclusionary rule grounds. But to repeat, the Fourth Circuit may now consider anew, after review of our opinion, how the good-faith exception applies here. And the very decision establishing that exception held that courts should feel free to “resolv[e] the Fourth Amendment is- sue” before the good-faith issue, either to better assess good faith or “to guide future action by law enforcement officers and magistrates.” United States v. Leon, 468 U. S. 897, 925 (1984). So contra the dissent, there is nothing advisory (or otherwise improper) in today deciding the Fourth Amendment issue on which we previously granted certiorari.  Cite as: 609 U. S. ____ (2026) 11 Opinion of the Court safeguard the privacy and security of individuals against arbitrary invasions by governmental officials.” Carpenter v. United States, 585 U. S. 296, 303 (2018) (quoting Camara v. Municipal Court of City and County of San Francisco, 387 U. S. 523, 528 (1967)). That purpose is central to decisions about whether a Fourth Amendment “search” has occurred. Our early search doctrine focused on whether law enforcement offi- cials “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 pro- tects people, not places.” And so we have long held that “property rights are not the sole measure” of a constitu- tional 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 rec- ognize as reasonable,” then governmental “intrusion into that private sphere generally qualifies as a search.” Ibid.5 —————— 5 The dissent suggests that this Court has tried to curtail Katz ever since deciding it, see post, at 10–11 (ALITO, J.); more energetically, the concurrence advocates overthrowing Katz and reverting to a solely prop- erty-based approach, see post, at 1–2, 4 (GORSUCH, J., concurring in judg- ment). But this Court has faithfully applied Katz for some 60 years. Our decision in Carpenter v. United States, 585 U. S. 296 (2018), responded to the same arguments made today (see, e.g., id., at 391–397 (GORSUCH, J., dissenting)) by reaffirming that Katz had “discredited the premise that property interests control” and that “privacy interests do not rise or fall with property rights.” 585 U. S., at 304, n. 1. And in saying as much, Carpenter had plenty of other decisions to cite. See, e.g., United States v. Jones, 565 U. S. 400, 411 (2012) (refusing to “make trespass the exclu- sive test”); Kyllo v. United States, 533 U. S. 27, 32 (2001) (stating that the Court has “decoupled violation[s] of a person’s Fourth Amendment rights from trespassory violation of his property”). Of course, sometimes the privacy and property approaches will “align,” and an opinion 12 CHATRIE v. UNITED STATES Opinion of the Court Whether an expectation of privacy counts as legitimate is less the result of any fixed set of rules than of “guideposts” stretching back to the Fourth Amendment’s beginnings. Id., at 305. From the founding onward, we have explained, the Fourth Amendment has sought to secure the “privacies of life” against the exercise of “arbitrary power.” Boyd v. United States, 116 U. S. 616, 630 (1886); see Carpenter, 585 U. S., at 305. So too we have recognized, and repeatedly, that the Amendment was designed “to place obstacles in the way of a too permeating police surveillance.” United States v. Di Re, 332 U. S. 581, 595 (1948); Carpenter, 585 U. S., at 305. Whatever the form of an attempted incursion, the Fourth Amendment protects Americans’ long-held convic- tion that no government official should have free access to the most closely kept aspects of their lives. 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 “en- hanced 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 de- gree 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 —————— adopting the one will resemble, in whole or part, an opinion adopting the other. Florida v. Jardines, 569 U. S. 1, 13 (2013) (KAGAN, J., concurring). That is not because the privacy-based approach is groping toward the more “coheren[t]” property-based one, as the concurrence suggests. Post, at 8 (GORSUCH, J.). It is simply because property law “naturally enough influence[s]” our “shared societal expectations” of what places and things count as private and should be free from governmental intrusion. Geor- gia v. Randolph, 547 U. S. 103, 111 (2006); see Carpenter, 585 U. S., at 304, n. 1 (“[P]roperty rights are often informative” in “determining which expectations of privacy are legitimate”). And when such an alignment of the two approaches occurs, then all the better.  Cite as: 609 U. S. ____ (2026) 13 Opinion of the Court from a person’s home was a