A lawyer for the US Department of Justice (DOJ) [official website] on Thursday defended the warrantless use of global positioning system (GPS) [JURIST news archive] devices on suspects' vehicles despite a January Supreme Court [official website] ruling declaring GPS tracking to be a "search" under the Fourth Amendment [text]. In oral arguments before the US Court of Appeals for the Ninth Circuit [official website] on Thursday, the DOJ argued that the Supreme Court's decision in United States v. Jones [SCOTUSblog backgrounder; JURIST report] did not require warrants for all GPS tracking [WSJ report] because the search could still be reasonable in certain situations. The Ninth Circuit originally ruled [decision, PDF] that the suspect did not have an expectation of privacy in his vehicle, but the court was asked to review its decision after the Supreme Court's ruling in Jones. The American Civil Liberties Union (ACLU) [advocacy website] filed an amicus brief [text, PDF; press release] supporting the defendant, arguing: "under Fourth Amendment jurisprudence, warrantless searches are presumptively unlawful. The exceptions to this rule are few and do not apply here."
The US Supreme Court ruled in January in the government's attachment of a GPS device to a vehicle, and its use of that device to monitor the vehicle's movements, constitutes a search under the Fourth Amendment. The federal government sought Supreme Court review after the US Court of Appeals for the District of Columbia Circuit ruled [JURIST reports] in 2010 that prolonged use of GPS to monitor suspects' vehicles violates the Fourth Amendment protection against unreasonable searches and seizures. Affirming the decision below, Justice Antonin Scalia delivered the opinion of the court, which was joined by Chief Justice John Roberts and Justices Anthony Kennedy, Clarence Thomas and Sonia Sotomayor, stating, "We have no doubt that such a physical intrusion would have been considered a "search" within the meaning of the Fourth Amendment when it was adopted." Justice Sonia Sotomayor also filed a concurring opinion. Justice Samuel Alito filed a concurring opinion, joined by Justices Ruth Bader Ginsburg, Stephen Breyer and Elena Kagan. Alito "would analyze the question presented in this case by asking whether respondent's reasonable expectations of privacy were violated by the long-term monitoring of the movements of the vehicle he drove."