The U.S. Department of Justice has asked the U.S. Supreme Court to overrule a federal appeals court decision that held police must get a warrant before attaching a global positioning device to a suspect’s car. The issues in the case involve whether use of a GPS tracking device is a “search” under the Fourth Amendment and whether a person has an expectation of privacy for his travel in public.

The government argues there is no reasonable expectation of privacy in a person’s movements from one place to another. It relies on a 1983 case, United States v. Knotts, which allowed police to install a beeper device in a can of chemical used to make drugs. The lower court said that case didn’t apply because it involved travel from one place to another, versus tracking a person’s movements at all times.

Sources:
http://legaltimes.typepad.com/blt/2011/04/doj-pitches-gps-surveillance-case-to-supreme-court.htmls:
http://www.abajournal.com/news/article/doj_asks_supreme_court_to_rule_cops_can_track_suspect_by_gps_without_a_warr/