Last week, we discussed the US Supreme Court ruling in the case of United States v. Jones. In a unanimous decision (Supreme Court pdf; archive pdf), the court held that police do need a valid warrant to place a GPS device on a vehicle. The majority opinion was premised on the fact that there was a physical trespass, or intrusion, by putting the device on the vehicle. It did not decide an issue of privacy, and a New York Times editorial criticizes the Supreme Court ruling for being too narrow:
The Supreme Court ruled unanimously on Monday that the police violated the Constitution when they hid a Global Positioning System tracking device on the car of Antoine Jones and monitored his movements for 28 days. It put law enforcement on notice that most GPS electronic surveillance will be suspect without a judge’s warrant.
As welcome as the ruling was, the court left too many questions unanswered. It did not say how long this kind of surveillance can go on before requiring a warrant or what types of crimes justify GPS monitoring. It did not say what the rule would be if the police had tracked Mr. Jones with a technology not hidden on his car.
The view of a five-justice majority is that the ancient legal concept of trespass is sufficient to prohibit the intrusion in this case. But a persuasive concurring opinion for four justices makes plain why that concept is unsuitable for addressing 21st-century technology. The result is a narrow holding: It upholds the overturning of Mr. Jones’s conviction for distributing cocaine. But the police could argue that a warrant is unnecessary for short-term GPS surveillance or, more importantly, for monitoring that involves no physical intrusion and might well win. […]
Justice Samuel Alito Jr. in the concurring opinion properly focuses instead on the “reasonable expectation of privacy” the court has used as its standard since 1967, explaining why GPS technology — which makes “long-term monitoring relatively easy and cheap” — requires thinking differently about what’s reasonable. […]
The full court recognized the intrusion on Mr. Jones’s right to privacy. A majority of the justices also recognized the wider threat to citizens’ privacy from this and other new technologies. Regrettably, their understanding is not reflected in the narrow holding.