Spencer S. Hsu
Washington Post 
Aug 7, 2010
A federal appeals court ruled for the first time Friday that police cannot use a Global Positioning System device to track a person’s movements for an extended time without a warrant, clearing the way for the Supreme Court to decide the privacy impact of the new surveillance technology in products such as cellphones and vehicle-navigation systems.
The decision, by a three-judge panel of the U.S. Court of Appeals for the D.C. Circuit, created a split with federal circuit courts in New York and California that have upheld warrantless GPS tracking of a vehicle by law enforcement. Feeding the national debate, a half-dozen state courts have issued conflicting rulings, while police across the country embrace GPS tools in hunting drug dealers, sexual predators and violent criminals.
In striking down the drug conviction of Antoine Jones, former co-owner of a District nightclub called Levels, the D.C. court said the FBI and District police overstepped their authority by tracking his movements round-the-clock for four weeks, placing a GPS monitoring device on his Jeep after an initial warrant had expired.
U.S. Circuit Judge Douglas H. Ginsburg, writing for a unanimous and ideologically diverse panel that included judges David S. Tatel and Thomas B. Griffith, said such surveillance technology represents a leap forward in potential government intrusion that violates constitutional protections against unreasonable searches.