Justices Rein In Police on GPS Trackers

From The Wall Street Journal:

The Supreme Court ruled Monday that police violated the Constitution when they attached a Global Positioning System tracker to a suspect's vehicle without a valid search warrant, voting unanimously in one of the first major cases to test privacy rights in the digital era.

The government said Federal Bureau of Investigation agents use GPS tracking devices in thousands of investigations each year. It argued that attaching the tiny tracking device to a car's undercarriage was too trivial a violation of property rights to matter, and that no one who drove in public streets could expect his movements to go unmonitored. Police were free to employ the tactic for any reason without showing probable cause to a magistrate and getting a search warrant, the government said.

The justices seemed troubled by that position at arguments in November, where the government acknowledged it would also allow attaching such trackers to the justices' own cars without obtaining a warrant.