A federal appeals court has ruled the government must obtain a warrant based on probable cause in order to track vehicles with GPS. It is the first time an appeals court has weighed in on the issue since the Supreme Court ruled that police monitoring through attaching a GPS to a suspect’s vehicle marks a constitutionally protected search. In a statement, the American Civil Liberties Union said the decision “ensures that the police cannot use powerful tracking technology without court supervision and a good reason to believe it will turn up evidence of wrongdoing.”