GPS AND THE RIGHT TO PRIVACY

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 Antonin Scalia wrote the majority opinion that says that the
police's action of putting the GPS device on Mr. Jones's car and
using it to monitor the car's movements constitutes a search the same
as entering his house without being invited and violates the Fourth
Amendment's prohibition against unlawful searches and seizures as it
is "tied to common-law trespass."

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.

His opinion explains convincingly why Justice Scalia's reliance on
the idea of trespass fails the same way the Supreme Court's reasoning
failed in early cases about wiretapping: The court found no
violations when taps were made on wires near, not in, houses
targeted. Similarly, if cars were to include GPS tracking devices as
smartphones now do, the majority holding "would provide no
protection" against using the devices for surveillance.

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.