npr:
In a major win for privacy rights, the U.S. Supreme Court ruled Friday that police must obtain a search warrant in order to get access to cellphone location information.
Chief Justice Roberts wrote the 5-to-4 decision, joining the court’s four liberals. The majority declared that the Fourth Amendment guarantees an expectation of privacy and that allowing police to obtain moment-by-moment tracking of an individual’s cellphone location is a kind of surveillance that the framers of the Constitution did not want to occur without a search warrant.