The Supreme Court ruled Thursday that the federal government violated the Fourth Amendment when it forced Google to hand over the location data of millions of Americans in search of a single bank robber. Writing for a six-justice majority, Justice Elena Kagan held that the reverse-location search of Google’s database was an unconstitutional search requiring a warrant backed by probable cause. The decision in Chatrie v. United States is the most significant constraint the Court has placed on law enforcement’s appetite for location data since Carpenter v. United States, 585 U.S. 296 (2018), and it landed on a Court that has almost never met a police power it didn’t like.
The technique, called geofencing, lets investigators draw a virtual fence around a bank, a park, a block, and then demand that Google — or any company holding a trove of users’ location histories — hand over the identities of everyone whose phones placed them inside the fence at a particular time. The government has used the technique to search first and develop suspicions later — to root through the location data of millions of Americans in search of a single bank robber, without ever establishing that the people whose data it swept up had done anything wrong. Okello Chatrie was convicted on the strength of evidence the police would not have found without first sifting through the movements of 19 people — and initially, millions — who were simply near a bank at the wrong hour.
Chatrie was convicted of robbing a bank in suburban Richmond, Virginia. Two months into a cold case, investigators obtained a warrant directing Google to identify every user whose location data placed them within a defined perimeter around the bank during the time of the robbery. Google’s initial search returned 19 names. After narrowing, police received three, went to Chatrie’s residence, and found a pistol matching the one captured on security footage along with roughly $100,000 in cash. Chatrie confessed. A jury convicted him. The search that trapped him also trapped everyone else whose phone was within the geofence.
The government’s defense of the warrant, on appeal, rested on the third-party doctrine: the 1970s rule that information voluntarily disclosed to a private party — telephone numbers dialed, per Smith v. Maryland, 442 U.S. 735 (1979); bank records, per United States v. Miller, 425 U.S. 435 (1976) — carries no reasonable expectation of privacy and therefore no Fourth Amendment protection. Under the government’s framework, every user who had carried a Google-enabled phone near a bank later robbed had, by virtue of having synced location data, voluntarily surrendered his constitutional interest in the government identifying him as a suspect it did not yet have. The solicitor general was effectively arguing that by leaving a default setting unchanged, tens of millions of Americans consented to being catalogued and turned over to the police on demand.
The doctrinal foundation of this position is not fabricated. The third-party doctrine is settled law. The government was not proposing to search without a warrant; it was proposing that the Fourth Amendment didn’t apply to the search in the first place, such that any warrant or no warrant was constitutionally equivalent. If carrying a smartphone constitutes voluntary disclosure of your movements to the police, Chatrie’s geofence warrant was a legal nullity — it didn’t need to comply with the Fourth Amendment, because the Fourth Amendment had already exited the building. The steel-man of the government’s position has internal coherence; a working-bar attorney can defend it on doctrinal terms.
At oral argument in April, the Court appeared ready to permit the government’s theory in cases like Chatrie’s. Several of the Republican-appointed justices who usually side with law enforcement seemed untroubled by the technique, and the tenor of the questioning suggested that the government would once again walk away with a broad surveillance tool intact. The eventual opinion came out the other way. The shift is traceable less to a sudden conversion among the Court’s conservatives than to Kagan’s ability to hold a majority that included, by all appearances, the Court’s three Democratic appointees and at least two of the justices who sit to their right. That the conservative supermajority fractured in a case where it didn’t have to is the analytical puzzle of the term.
Chatrie is the Carpenter architecture extending to its next logical application. Carpenter held that seven days of cell-site location information from a wireless carrier is a search, even though the records were held by the carrier rather than the user. The principle was that the transformation of the phone into a ubiquitous tracking device — producing, as the Court put it, an all-encompassing record of the holder’s whereabouts — does not dissolve Fourth Amendment protection simply because the data lives with a company instead of in a pocket. The two practices — collecting cell-site location information and running reverse-location searches — are analytically identical at the doctrinal level the Carpenter framework governs. In both, the government is obtaining, from a third party, a comprehensive record of individual movements that, under the government’s theory, carries no constitutional protection at all.
Chatrie applies that principle to the reverse query, resolving the question of whether geofence warrants violate the Fourth Amendment in the affirmative. The government cannot ask a company to search its entire user base for everyone within a geographic perimeter and claim that the Fourth Amendment is absent because users voluntarily gave Google their location data. Kagan’s majority rejected that claim outright, recognizing that the Fourth Amendment does not vanish because a technology company’s terms of service are long and nobody reads them.
The holding does not eliminate geofence warrants. It restricts them: a warrant is required; probable cause is required; the government cannot treat the geofence query as a constitutional free-fire zone. The doctrinal work of applying those requirements belongs now to the lower courts, which must decide whether probable cause can be particularized to a specific perimeter-and-time query, what evidentiary showing suffices to justify the radius of that perimeter, and how a reverse-location sweep differs doctrinally from the targeted cell-site location information pull at issue in Carpenter. Geofence warrants remain the most indiscriminate tool in the location-tracking arsenal, but officers who want to know where a suspect has been can still get a warrant for that person’s specific location records, and the Kagan opinion does nothing to disturb that practice.
What the Court did, finally, was to reject the government’s central premise that a person’s location becomes the police’s business the moment it passes through a server farm. Twice in eight years the Court has refused to permit the technological reality of the ubiquitous tracking device to operate as a Fourth Amendment bypass. The Carpenter architecture is genuine constraint. On the question of geofence dragnets, it held. For a Court that has spent two decades annexing new territory for police surveillance, that sentence alone is news.