By Julia Angwin | WSJ | Feb. 25, 2012

The Supreme Court’s recent ruling overturning the warrantless use of GPS tracking devices has caused a “sea change” inside the U.S. Justice Department, according to FBI General Counsel Andrew Weissmann.

Mr. Weissmann, speaking at a University of San Francisco conference called “Big Brother in the 21st Century” on Friday, said that the court ruling prompted the FBI to turn off about 3,000 GPS tracking devices that were in use.

These devices were often stuck underneath cars to track the movements of the car owners. In U.S. v. Jones, the Supreme Court ruled that using a device to track a car owner without a search warrant violated the law.

After the ruling, the FBI had a problem collecting the devices that it had turned off, Mr. Weissmann said. In some cases, he said, the FBI sought court orders to obtain permission to turn the devices on briefly – only in order to locate and retrieve them.

Mr. Weissmann said that the FBI is now working to develop new guidelines for the use of GPS devices. He said the agency is also working on guidelines to cover the broader implications of the court decision beyond GPS devices.

For instance, he said, agency is now “wrestling” with the legality of whether agents can lift up the lid of a trash can without committing trespass. The majority opinion in U.S. v. Jones held that the agents had trespassed when placing the GPS device on a car without warrant.

He said the agency is also considering the implications of the concurring justices – whose arguments were largely based on the idea that a person has a reasonable expectation of privacy in the totality of their movements, even if those movements are in public.

“From a law enforcement perspective, even though its not technically holding, we have to anticipate how it’s going to go down the road,” Mr. Weissmann said.