If police do not need a warrant to observe someone in public places, does that mean they do not need a warrant when they use a GPS device to track his car? The Supreme Court is considering that question in a case involving a Washington, D.C., nightclub owner who was convicted of conspiring to sell cocaine and sentenced to life in prison based largely on information about his movements collected via a GPS tracker that police surreptitiously attached to his Jeep.
When the U.S. Court of Appeals for the D.C. Circuit overturned the conviction in 2009, Judge Douglas Ginsburg said GPS tracking is qualitatively different from the sort of warrantless public surveillance the Supreme Court has allowed. "A person who knows all of another's travels," Ginsburg wrote, "can deduce whether he is a weekly church goer, a heavy drinker, a regular at the gym, an unfaithful husband, an outpatient receiving medical treatment, an associate of particular individuals or political groups—and not just one such fact about a person, but all such facts."
The Justice Department argues that the Fourth Amendment does not apply because people do not have a reasonable expectation of privacy when they drive on public streets. "If you win this case," Justice Stephen Breyer told Deputy Solicitor General Michael Dreeben during oral arguments in November, "then there is nothing to prevent the police or the government from monitoring 24 hours a day the public movement of every citizen of the United States," which "sounds like 1984." Dreeben replied that we can worry about that when it happens.