Today, in a 5-4 decision, the US Supreme Court ruled that the government’s acquisition of information regarding an individual’s location based on a cell phone record amounts to a Fourth Amendment search and generally requires a warrant.  In Carpenter v. United States, the government obtained nearly 13,000 location points on Carpenter’s movements over a 127-day period from Carpenter’s wireless carrier under the Stored Communications Act (SCA).  The standard for obtaining information under the SCA is much lower than the probable cause showing required for a warrant.  The government used these cell phone records to show that Carpenter’s phone was near four locations that had been robbed when those robberies occurred and obtained a conviction.  In reversing the decision of the Sixth Circuit and remanding the case, the Court held that individuals have a reasonable expectation of privacy in their physical movements.

Chief Justice Roberts delivered the 119-page opinion for the majority, joined by Justices Ginsburg, Breyer, Sotomayor and Kagan. Justices Kennedy, Alito, Thomas and Gorsuch each filed dissenting opinions.