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.