The Third Circuit decided this week that installing a GPS device on a car requires police to obtain a search warrant. The case, United States v. Katzin, builds upon the Supreme Court’s decision in United States v. Jones, which held that placing a GPS device on a car is a “search” for Fourth Amendment purposes. Katzin addresses when that search is reasonable. The court considered various exceptions to the warrant requirement in other contexts, but concluded that none applies here. The court recognized that it was the first circuit to address this issue.