SCOTUS just issued its biggest privacy ruling in a decade

Supreme Court Rules Warrant Required for Geofence Searches of Smartphone Location Data

In a 6-3 decision, the Supreme Court held that law enforcement must obtain a warrant supported by probable cause before accessing certain smartphone location records through geofence requests to technology companies. The ruling in Chatrie v. United States addressed the application of the Fourth Amendment to location history data stored by Google.

The majority consisted of Chief Justice John Roberts and Justices Brett Kavanaugh and Neil Gorsuch joining Justices Sonia Sotomayor, Elena Kagan, and Ketanji Brown Jackson. The decision marks the Court’s first substantive examination of digital location surveillance since its 2018 ruling in Carpenter v. United States, which addressed cell-site location information. The case reached the Court after lower courts reviewed a 2019 bank robbery investigation in which police used a geofence warrant to obtain data from Google.

A geofence warrant directs a company to identify devices present within a defined geographic area during a specified time period. Unlike a traditional warrant that names a particular person or place based on individualized suspicion, this method begins with location data and works backward to identify individuals. In the Chatrie investigation, police drew a boundary around a bank and requested records for devices inside that area during the time of the robbery. The area also included a church and nearby residences and businesses.

The technique relies on location data that Google collects from users who have enabled relevant settings on Android devices or certain applications. Google records location points at intervals as frequent as every two minutes and includes latitude, longitude, and sometimes elevation. Police in the Chatrie matter followed a three-step protocol approved in advance by a magistrate. First, Google returned anonymized identifiers for 19 devices inside the geofence. Investigators then selected nine of those devices for additional location history covering roughly two hours before and after the robbery. Finally, investigators requested identifying information for three accounts.

Justice Elena Kagan wrote the majority opinion. It concluded that the government’s request to Google constituted a search under the Fourth Amendment and therefore required closer scrutiny of the warrant’s particularity. The opinion held that the third-party doctrine, which limits Fourth Amendment protections for information voluntarily shared with companies, did not apply to the location history at issue. Justice Gorsuch filed a separate opinion reaching the same result on different grounds. The Court vacated the lower court’s judgment and remanded the case for further proceedings on whether the specific warrant satisfied Fourth Amendment requirements.

Justice Samuel Alito dissented, joined by the remaining justices. The dissent expressed concern that the majority’s reasoning could affect a range of digital records held by third parties.

Stevie Glaberson, director of research and advocacy at Georgetown Law’s Center on Privacy and Technology, filed an amicus brief in the case on behalf of the center along with the Electronic Frontier Foundation and the American Civil Liberties Union. In an interview, Glaberson described the mechanics of geofence warrants and the data flows involved. Glaberson noted that the three-step process used in Chatrie allowed investigators to obtain information about multiple individuals who were never suspects. The initial return of 19 devices and the subsequent request for detailed histories of nine accounts necessarily captured movements of people unrelated to the robbery.

Glaberson stated that Google had already altered its response procedures for similar requests by the time of the Supreme Court argument. The company now requires investigators to return to a judge between steps rather than proceeding under a single warrant. Other companies maintain different policies for location data requests, and some continue to respond to geofence-style inquiries.

The Center on Privacy and Technology has conducted research on government access to commercial location databases. One study found that, as of 2021, records sufficient to locate a majority of American adults appeared in Department of Homeland Security immigration databases accessible to Immigration and Customs Enforcement and Customs and Border Protection. Glaberson observed that once location information enters such systems, it can be queried without regard to whether the subject is under investigation for a specific offense.

The Chatrie decision leaves several questions for lower courts. These include the level of particularity required in the geographic and temporal scope of a geofence warrant and the circumstances under which investigators may obtain identifying information for accounts that do not match the original target. The ruling does not address every form of location tracking used by law enforcement, such as real-time cell-site simulators or purchases of commercial location data from brokers.

The case originated from a 2019 robbery of a bank in Virginia. Investigators obtained the geofence data, identified Okello Chatrie as a possible match based on his device’s presence near the bank, and later charged him. Chatrie moved to suppress the evidence, arguing that the warrant lacked sufficient particularity. Lower courts upheld the search, and the Supreme Court granted review limited to the Fourth Amendment question.

The majority opinion referenced the Carpenter precedent repeatedly, noting similarities between cell-site records and the detailed location history maintained by Google. Both forms of data can reveal movements over extended periods with precision that was not available when the Fourth Amendment was adopted. The Court declined to decide whether every geofence request requires a warrant, instead holding that the request in this case triggered Fourth Amendment scrutiny.

Legal observers expect additional litigation testing the boundaries of the ruling. Courts will likely confront questions about warrants that cover larger areas or longer time windows, as well as requests directed at companies other than Google that maintain comparable datasets. The decision does not alter existing requirements for traditional warrants that name specific individuals or accounts from the outset.