David Kravits of Wired reports that the Supreme Court issued its decision in United States v. Jones, holding that law enforcement must get a probable cause warrant from a judge to track a vehicle by covertly installing a GPS device. The 5-4 decision was so split because four justices refrained from deciding whether such tracking of a duration less than one month constituted a search.

Justice Scalia wrote for the majority and was joined by Justices Kennedy, Thomas, Sotomayor, and Chief Justice John Roberts. This case involved a month of tracking, and all agreed that it constituted a search in that context. However, Justices Alito, Ginsberg, Breyer and Kagan filed a concurrence warning that one's reasonable expectations of privacy may not be implicated by GPS surveillance of a shorter duration than the period at issue here.

The 34-page opinion is embedded below.

Image via Jason Dunn; PDF via SupremeCourt.gov