US v. Jones
The majority opinion in US v. Jones 565 U. S. ____ (2012) , written by Justice Scalia, held that the attachment of the GPS device to the vehicle was a trespass and thus a search. The analysis ended there. It did not even need to reach the issue of how long Jones was monitored (although one of the concurring opinions took that into account).
Katz did not repudiate the
understanding that the Fourth Amendment embodies a particular
concern for government trespass upon the areas it enumerates. The
Katz reasonable-expectation-of-privacy test has been added to, but
not substituted for, the common-law trespassory test.
This leaves open whether police can attach a GPS device to a car before it is obtained by a defendant and then later use that GPS device to monitor the defendant's movements. Based on the concurrences in Jones there are at least five votes for the principle that long term GPS surveillance is a search (Justices Alito, Ginsburg, Breyer, Kagan, Sotomayor1) and at least one vote (Justice Sotomayor) for the principle that any GPS surveillance is a search. The latter holding would require overruling or distinguishing Karo and Knotts, two cases that allowed the placement of a surveillance device into things before the defendant purchased them.2
Effect on US v. Pineda-Moreno
Regarding, US v. Pineda-Moreno, on remand to the 9th Circuit for consideration in light of Jones, the 9th Circuit said:
Jones has made clear that the agents conducted Fourth
Amendment searches when they attached tracking devices to
Pineda-Moreno’s Jeep and used the devices to monitor the
Jeep’s movements. Indeed, for purposes of this remand we
will assume, without deciding, that those warrantless searches
would be unreasonable under the Fourth Amendment after
Jones.
But Jones had not been decided when those searches
occurred. And when the agents attached and used the mobile
tracking devices that yielded the critical evidence, they did so
in objectively reasonable reliance on then-binding precedent.
Relying on Davis v. United States, 564 U.S. 229 (2011), the 9th Circuit declined to suppress the evidence obtained against Pineda-Moreno.
Searches conducted in objectively reasonable reliance on binding appellate precedent are not subject to the exclusionary rule.
1. While Justice Sotomayor did not join Justice Alito's concurrence, she wrote: "I agree with Justice Alito that,
at the very least, “longer term GPS monitoring in investigations
of most offenses impinges on expectations of
privacy.”"
2. In a pre-Jones dissent to the denial of a petition for en banc rehearing of US v Pineda-Moreno, Chief Judge Kozinski distinguished Knotts this way: The electronic tracking devices used by the police in this
case have little in common with the [beepers] in
Knotts. [...]
Beepers could help police keep vehicles in view when following
them, or find them when they lost sight of them, but
they still required at least one officer—and usually many
more—to follow the suspect. The modern devices used in
Pineda-Moreno’s case can record the car’s movements without
human intervention—quietly, invisibly, with uncanny precision.