Carpenter v. United States

Background

Timothy Carpenter, a man charged in a series of armed robberies, had his wireless carriers produce cell‑site location information (CSLI) after the FBI identified phone numbers tied to suspects. Prosecutors obtained court orders under the Stored Communications Act (§2703(d)), and MetroPCS and Sprint produced records covering many days—12,898 location points over 127 days (about 101 points per day). The records were used at trial and the Sixth Circuit said Carpenter had no reasonable privacy expectation because he had shared the data with his carriers.

Reasoning

The Court asked whether the Government’s acquisition of historical CSLI is a Fourth Amendment search. It explained that these records are detailed, day‑to‑day chronologies of a person’s movements—similar in privacy risk to long‑term GPS monitoring—and that existing third‑party cases about ordinary business records did not fit. The majority declined to extend the older bank/phone‑number rules to cover exhaustive location logs. It held that getting historical CSLI is a search and that the Government generally needs a warrant supported by probable cause; a lower “reasonable‑grounds” showing under §2703(d) is not enough. The opinion stressed narrowness: real‑time tracking, “tower dumps,” national‑security techniques, and other record types were left open.

Real world impact

Going forward, police will usually need a warrant to compel historical CSLI from carriers, though case‑specific exceptions (for example, exigent emergencies) may still allow warrantless collection. The decision protects long‑term location privacy and notes carriers often keep records for years; it also directs lower courts and lawmakers to work out unresolved questions.

Dissents or concurrances

Several Justices dissented, arguing the decision departs from long‑standing rules about third‑party business records and that Congress’s procedural scheme should remain operative.