SCOTUS 6-3 in Chatrie v. United States requires probable cause for geofence warrants

The decision holds that individuals retain a reasonable expectation of privacy in comprehensive location histories even when generated through optional services. Justice Kagan's majority opinion rejected the government's third-party doctrine argument, noting that users enable location features to access core device functions rather than to consent to law enforcement access. This directly extends the 2018 Carpenter precedent, which addressed historical cell-site records, to the more granular and continuous data produced by geofence requests.

Data from the Richmond bank robbery investigation showed police obtained 19 device identifiers from a two-hour geofence without individualized suspicion. The Court found this volume of movement data reveals protected associations, aligning with Sotomayor's concurrence on short-term tracking. Lower courts had split on similar warrants; post-Carpenter filings show geofence use rose in 42 federal districts before this ruling.

Operationally, Google and other providers must now demand warrants meeting probable cause standards before releasing location history. Agencies will shift toward narrower requests or alternative surveillance, increasing administrative load. The ruling leaves open questions on real-time geofence and anonymized data aggregation, setting up further litigation.

Future compliance will require updated internal policies at tech firms and revised training for federal and state investigators to avoid suppression of evidence obtained under prior practices.