The U.S. Supreme Court rules that law enforcement must obtain a warrant before conducting broad searches that use cell phone location data to identify people’s whereabouts. In its decision issued Monday, the Court applies constitutional privacy and search-and-seizure principles to a technology-driven investigative method that relies on records of cell phone users’ location history. The ruling limits investigative practices that allow authorities to collect or review large swaths of location information to determine who was near a crime scene. Under the Court’s reasoning, location data sweeps that go beyond targeted, individual suspicion require judicial authorization through a warrant. The decision addresses how warrants should apply when agencies use historical location information to connect individuals to specific locations or events. The Court’s holding narrows the circumstances in which such data can be gathered without prior review by a judge, emphasizing that the scope of the data collection matters for constitutional protections. The ruling is expected to affect how police departments and other agencies plan and conduct investigations that use cell phone location records.