Chatrie v. United States

Majority — Kagan

Joined by: Roberts, Sotomayor, Kavanaugh, Jackson

The majority held that individuals have a reasonable expectation of privacy in their cell-phone location information, and that Google's Location History is even more sensitive than the cell-site location data the Court already protected in Carpenter v. United States (2018) — it is more precise (within 20 meters vs. up to 4 square miles), records location far more frequently (every 2 minutes vs. roughly 101 times per day), and can even detect which floor of a building a person is on. The Court rejected the government's argument that only a short window of location data (two hours here) falls outside Fourth Amendment protection, reasoning that the Amendment does not have an "on/off switch" based on how much information is gathered — even brief surveillance can reveal deeply private details, and the government's ability to cherry-pick any time window from an all-encompassing database does not reduce the invasiveness of the intrusion. The Court also rejected the "third-party doctrine" — the legal rule that people lose privacy rights in information they share with others — finding that Location History is not truly "shared" in any meaningful sense, because Google repeatedly pressures users to enable the service (sometimes warning their devices won't work without it) without disclosing how precise or frequent the tracking is or that it could be handed to police. Finally, the majority reasoned that treating every individual app or feature as a separate voluntary choice misunderstands how smartphones work — using apps and services is the entire point of carrying a smartphone, and ordinary cell-phone use should not strip people of Fourth Amendment protection.

Dissent reasoning

Justice Alito's dissent argued on two main grounds. First, he contended the Court should not have decided this case at all, because a majority of the Fourth Circuit had already ruled that the "good-faith exception" to the exclusionary rule — which allows evidence obtained under a reasonable but flawed warrant to be used at trial — independently supported Chatrie's conviction, and nothing in the majority's opinion disturbs that holding; the constitutional ruling therefore has no effect on the outcome and amounts to an advisory opinion. Second, on the merits, the dissent argued that Carpenter itself was a significant departure from traditional Fourth Amendment law, but that even under Carpenter's own reasoning, this case is different in three key ways: the data here covered only two hours (not 127 days), the geofence was centered on a public place (a credit union) rather than tracking someone's comprehensive movements everywhere, and Location History is a genuinely voluntary service that most Google users choose not to enable — unlike cell-site records, which are generated automatically by any use of a phone. The dissent warned that the majority's rule — requiring a warrant any time police access any cell-phone location data from a third party, regardless of duration or voluntariness — abandons the limits Carpenter itself claimed to set and will create sweeping, unresolved questions about when warrants are needed for other digital records like purchase histories, search histories, and payment logs. Justice Barrett's separate dissent agreed that under existing precedent, including Carpenter, Chatrie had no reasonable expectation of privacy in data about his public movements that he voluntarily shared with Google.