The Supreme Court said it will hear a case (PDF) regarding whether or not law enforcement can access certain types of cell location data without a warrant.
As it stands today, the government does not need to get a warrant when seeking location and other information held by phone companies. In a 1979 court case, Smith v. Maryland, the Supreme Court decided that a suspect had no reasonable expectation of privacy (with respect to his location) because he willingly dialed phone numbers into his home phone, thus providing the phone company, a third party, with that data. Personal data held by third parties is not as protected as information held by the actual suspect.
This third-party doctrine is still being applied today in lower courts and is what allows law enforcement to seek suspects’ historical movements from cell phone companies without obtaining a warrant. Since the 1979 case, the Supreme Court has ruled that the government needs a warrant to seek GPS data, as well as to search cell phones of suspects. A new case, Carpenter v. United States, argues that the third-party doctrine is, essentially, outdated and that law enforcement seeking such data should be required to obtain a warrant as it would for GPS data.
More specifically, Carpenter alleges that gleaning location data from a third party without a warrant violates the Fourth Amendment.
The Supreme Court will hear Carpenter v. United States to provide the needed guidance moving forward.
