The Court ruled today that attaching a GPS device to a suspect's car and using to monitor the car's movements on public streets is indeed a search for Fourth Amendment purposes. It was pleasantly surprising to see a unanimous Court go all
on the government's no-search argument.
The vote was unanimous, but the reasoning was split. Scalia's position, which garnered five votes (himself, Roberts, Kennedy, Thomas and Sotomayor), is that traditional trespass-based Fourth Amendment analysis -- which was good enough for the Framers and is therefore good enough for us, goddamnit -- plainly mandates the conclusion that what the government did here was a search because in 1791 actions like the ones at issue here would have constituted a common law trespass to chattels. We needn't bother ourselves with that Johnny-Come-Lately "reasonable expectation of privacy" shit, which dates back only to 1967, because subsequent decisions that line of cases only supplements (but doesn't displace) trespass analysis. The government waived its alternative argument that the search was reasonable, thereby comporting with the 4th, by failing to raise it in the lower courts.
Alito and three other justices (Ginsburg, Breyer and Kagan) believe that continued use of the old school trespass analysis is both silly and unwarranted under current law. The reasonable expectation of privacy test should be the only rule. Alito wrote that relatively short-term GPS use would not qualify as a 4th Amendment search, but the 28 days at issue here crossed the line. Alito doesn't say where the line is or how we should go about finding it. That, he says, is for future cases.
Sotomayor wrote a short concurring opinion generally agreeing with the narrow approach Scalia used to resolve this particular case but suggesting that under reasonable-expectation analysis the time has come to shitcan "the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties" as "ill suited to the digital age."
U.S. v. Jones (pdf, 34 pages)