Supreme Court Court Rejects Willy-nilly GPS Tracking

The Supreme Court said Monday that law enforcement authorities might need a probable-cause warrant from a judge to affix a GPS device to a vehicle and monitor its every move — but the justices did not say that a warrant was needed in all cases.
The convoluted decision (.pdf) in what is arguably the biggest Fourth Amendment case in the computer age, rejected the Obama administration’s position that attaching a GPS device to a vehicle was not a search. The government had told the high court that it could even affix GPS devices on the vehicles of all members of the Supreme Court, without a warrant.

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