Chatrie v. United States, No. 25–112 (U.S. June 29, 2026) (Opinion by Kagan, joined by Roberts, Sotomayor, Kavanaugh, and Jackson; Gorsuch concurs in the judgment)

Introduction

The facts in Chatrie look daunting — a bank robbery solved through a multi-step “geofence” warrant served on Google, full of unfamiliar ideas like anonymized device lists, “Location History,” and twenty-meter location pings. But don’t get bogged down in the details.

The tech is mostly a sideshow. Chatrie ends up deciding almost nothing about geofencing in particular, since the Court remands for a determination of whether the Government’s examination of Location History here was “reasonable” under the Fourth Amendment. Rather, the case principally shows how the Amendment’s oldest principles, in particular its analog-era expectations of privacy, carry into the digital age.

Chatrie is a blueprint for applying the Fourth Amendment to new technology. By a 6–3 vote (but Gorsuch concurs only in the judgment), Kagan held for the Court that “[a]n 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.” The police conduct a “search” within the meaning of the Fourth Amendment search when they “gain[] access to Location History.” Slip op. at 2.

The Court held only that a search occurred, not whether it was reasonable and otherwise complied with the warrant, probable cause, and particularity requirements of the Fourth Amendment. Those questions, as well as the role of Leon’s good-faith exception, return to the Fourth Circuit. Slip op. at 10 n.4, 29–32.

The Robbery and the Three-Step Warrant

In May 2019, a man robbed a credit union in Virginia of $195,000. Slip op. at 6–7. Witnesses and videos showed him walking to the bank from a nearby church “while appearing to talk on a cell phone,” and then leaving on foot toward a residential area. The investigation stalled. Id. at 7.

Police obtained a geofence warrant from a magistrate, directed to Google, seeking data generated by its Location History service. This service, enabled by more than 500 million users, logs a phone’s position “every two minutes or so,” within roughly twenty meters, and can even estimate which floor of a building the phone is on. Id. at 3.

Location History “is what it sounds like—a timestamped record of every place a cell phone has been.” Slip op. at 3. Switched on, it keeps a timestamped record of everywhere a phone has been and feeds it back to its owner — a “Timeline” of past travels, real-time updates on the daily commute, and maps and recommendations drawn from the user’s usual movements. Id. at 5. It functions as a “personal journal” of one’s movements, something people use “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.” Id. at 18.

But the data has another function “unknown to most users”: it lets police, via geofence warrants, reconstruct who was near a crime scene and thus “solve hard-to-solve crimes.” Slip op. at 6.

The warrant in Chatrie set out a three-step protocol. At step one, Google would produce anonymized location data for every phone inside a 150-meter circle around the credit union for a one-hour period — thirty minutes on either side of the robbery. Slip op. at 7. At step two, after officers “attempt[ed] to narrow down the list” by comparing that data “against the known time and location information that is specific to this crime,” Google would hand over additional anonymized data for that subset, but now expanded spatially and temporally — spanning a two-hour window and covering locations both inside and outside the geofence. Slip op. at 7–8. At step three, after a further narrowing by police through the same method, Google would at last disclose identifying information — names, email addresses, phone numbers — for whichever cellphones remained. Slip op. at 8.

The warrant said almost nothing about how officers were to do the narrowing at steps two and three. Slip op. at 8. And the magistrate who issued the warrant was involved only at its outset.

Following this protocol, Google disclosed to the police that 19 phones (anonymously) satisfied step one and that 9 phones (anonymously) satisfied step two. At the third step, after the police further narrowed the list to 3 phone, Google disclosed the identity of the users. “One of the three was Chatrie, whose Location History 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.” Slip op. at 8.

Chatrie was arrested and moved to suppress the geofence data as the product of an unreasonable Fourth Amendment search. He lost in the district court and in the Fourth Circuit.

The holding and its rationale

The Court held that “police officers invade a cell-phone user’s reasonable expectation of privacy when they access his Location History,” and that “[i]t does not matter if the time period scrutinized was only two hours” or “that the materials obtained were handed over by a third-party tech company.” Slip op. at 29. This flowed directly from Carpenter v. United States, 585 U.S. 296 (2018), since “[e]verything Carpenter relied on” to treat cell-site location information (CSLI) as a search “applies as well or better” to Location History. Slip op. at 16–18.

Several key moves led to the holding.

First, the familiar test from Katz v. United States, 389 U.S. 347 (1967), determines when a “search” has occurred: “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.” Slip op. at 11. The Court again rejects a “solely property-based approach” to privacy, as advocated by Gorsuch in his concurrence, confirming that “privacy interests do not rise or fall with property rights” even if “sometimes the privacy and property approaches will align.” Id. n.5 (quoting Carpenter, 585 U.S. at 304 n.1).

Second, what makes a privacy expectation “legitimate” (i.e., objectively reasonable) turns on “guideposts” “stretching back to the Fourth Amendment’s beginnings.” Slip op. at 12. The pre-digital world supplies the measure: The Court’s aim is the “’preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted.’” Id. (quoting Kyllo v. United States, 533 U.S. 27, 34 (2001)). Before the rise of CLSI and Location History, the government “simply could not . . . secretly monitor and catalogue every single movement” of a person, and “[a] new technology should not transform what individuals had reasonably thought they could withhold from the Government.” Slip op. at 14–15.

Third, the Court reaffirms the privacy-protecting core of the Fourth Amendment: It guards against governmental surveillance and is antithetical to a “virtual panopticon.” Slip op. at 12 & 21.[1] The Amendment “was designed to place obstacles in the way of a too permeating police surveillance” and “protects Americans’ long held conviction that no government official should have free access to the most closely kept aspects of their lives.” Id.

Combining these principles means that police looking through Location History data violates a person’s legitimate expectation of privacy. “Prior to the digital age, pursuing a suspect for any extended period of time was difficult and costly and therefore rarely undertaken. 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.” Slip op. at 14. And, to repeat, “[a] new technology should not transform what individuals had reasonably thought they could withhold from the Government.” Id.

What’s left on remand

Holding that a search occurred “does not resolve this case, because the Fourth Amendment prohibits only searches that are unreasonable.” Slip op. at 29. The Court then punts the question to the Fourth Circuit.

But it gives some guidance. A “search” generally requires a warrant from “a neutral and detached magistrate,” issued only on “probable cause” and with “the scope of the authorized search . . . set out with particularity.” Slip op. at 29. Probable cause means a “fair probability that contraband or evidence of a crime will be found” in the place searched, slip op. at 30 (quoting Illinois v. Gates, 462 U.S. 213, 238 (1983)). And particularity requires a warrant “carefully tailored to its justifications,” not one that takes on “the character of the wide-ranging exploratory searches the Framers intended to prohibit,” slip op. at 30 (quoting Maryland v. Garrison, 480 U.S. 79, 84 (1987)).

Practice pointers

Chatrie reach well past geofencing. Four aspects of the case are particularly important for future litigation.

First, what is searched controls; how much the government peeks does not. The Government’s lead argument was durational — two hours of location data (unlike the seven days of CSLI in Carpenter) is too little to be a search. The Court rejected the premise: “we have never understood Fourth Amendment protections as kicking in only once an intrusion ‘goes too far.'” Slip op. at 20 (quoting Pennsylvania Coal Co. v. Mahon, 260 U.S. 393, 415 (1922)).

“Where the Fourth Amendment applies, it applies — regardless of ‘the quality or quantity of information’ the government obtains.” Slip op. at 20 (quoting Kyllo, 533 U.S. at 37). “The amendment makes no exceptions for the officer ‘who barely cracks open the front door and sees nothing but the nonintimate rug on the vestibule floor.’” Id. (quoting id.).

Second, the third-party doctrine does not reach ordinary uses of a phone. The Government argued that by enabling Location History, Chatrie voluntarily shared his movements with Google (the third party) and thus forfeited his privacy interest. The Court refused to apply the doctrine because Location History “is ‘not truly shared,’ in the normal sense of wanting a third party to see or use it.” Rather, its exposure to Google “is merely what happens when a user avails himself of one of the services on his cell phone.” Slip op. at 25–26

“Pretty much everything a person does on a smartphone requires some kind of opt-in”— sending a Gmail, uploading to Google Photos, adding a calendar entry, for instance — and “[t]he point of carrying smartphones is to use what is on them.” Slip op. at 28. Thus, “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.” Slip op. at 28–29.

After Chatrie, therefore, the third-party doctrine has almost no bite left as applied to a phone. The doctrine runs on consent: by “voluntarily convey[ing]” information to a third party, a user assumes the risk it will be handed to the government. Slip op. at 24. But Chatrie drains the premise: A user doesn’t “share[e] private information with third parties . . . just by doing the ordinary things cell-phone users do.”

Third, although Chatrie involves only location data, its logic almost certainly applies to other cloud-based content like emails, photographs, and calendars. The Court twice grouped Location History with a user’s emails, photographs, and calendars as “private materials” that “a user reasonably views as his own” even when “stored on Google’s servers,” slip op. at 18 & 25, and held that storing such material with a provider is not the kind of “sharing” the third-party doctrine reaches, slip op. at 28.

Finally, the privacy baseline is the analog past, which cuts in defendants’ favor. Like it did with Bruen in the Second Amendment context, the Court fixes the right by a historical baseline: The degree of privacy that we have now is “that degree of privacy against government that existed when the Fourth Amendment was adopted.” Slip op. at 12 (quoting Kyllo, 533 U.S. at 34).

In 1787 — and throughout the analog age — individual privacy was robust because surveillance was limited by technology and lack of resource. No engine of “tireless and absolute surveillance” existed and tracking a person’s movements was “difficult and costly and therefore rarely undertaken.” Officers “simply could not . . . secretly monitor and catalogue every single movement.” Slip op. at 14, 18.

That vanished-world privacy is the privacy we still hold, at least under the Fourth Amendment. Courts are “obligated . . . to ensure that the ‘progress of science’ does not erode Fourth Amendment protections.” Slip op. at 32 (quoting Carpenter, 585 U.S. at 320).

[1] A panopticon is an institutional design (mostly for prisons) that “allow[s] all prisoners of an institution to be observed by a single [unseen] prison officer, without the inmates knowing whether [] they are being watched.” Wikipedia.