The ruling was in the United States versus Skinner. The judge ruled that the DEA (Drug Enforcement Agency) did not violate the U.S. Constitution when they used data from a cell phone a dealer used to both identify him and track his location. The panel of three judges
split 2 to 1 on the ruling.
Data obtained from the dealer's disposable cell phone showed that the dealer was going to use his mobile home to deliver a large shipment of marijuana from Arizona to Tennessee. The police had obtained authority
to trace whom he called and when but were not authorized to listen in on the calls.
Having used the GPS information to determine his exact location, police dogs were able to find the mobile home and the dealer was arrested for drug trafficking. The dealer appealed, arguing that the DEA had violated the Fourth Amendment to the Constitution by not obtaining a warrant to obtain the cell phone data. The Fourth Amendment is intended to protect people from "unreasonable searches and seizures" without probable cause and also the issuance of a warrant.
However, the court claimed that cell phone use is a public not a private action. There is no protection under the Fourth Amendment for information obtained from the use of the cell phone. Judge John Rogers
who wrote the majority decision said the dealer:
“did not have a reasonable expectation of privacy in the data given off by his voluntarily procured pay-as-you-go cell phone. If a tool used to transport contraband gives off a signal that can be tracked for location, certainly the police can track the signal.”
This ruling extends the power of the police to track information derived from your cell phone use with no warrant or probable cause. There seems to be a steady progression of rulings that for the most part have extended the power of the government to obtain information about everyone and anyone. As reported a while back in Digital Journal
a recent ruling held that the government cannot be sued for using illegal warrantless wiretaps.