Government acquisition of cell-site records is a Fourth Amendment search, and, thus, generally requires a warrant. Decided June 22, 2018 (argued November 29, 2017). Opinion of the Court: John Roberts → go there Dissenting: Kennedy, Thomas, Alito. Applied: the Fourth Amendment → go there Topic: Fourth Amendment rights. Carpenter v. United States, 585 U.S. 296 (2018), is a landmark United States Supreme Court case concerning the privacy of historical cell site location information (CSLI). The Court held that government entities violate the Fourth Amendment to the United States Constitution when accessing historical CSLI records containing the physical locations of cellphones without a search warrant. Wiki link