Back in 2004, D.C. police decided that Antoine Jones was a bad dude and needed watching. Employing a spy store full of surveillance tools, the police obtained a court order allowing them to install a GPS device on the Jeep that Mr. Jones routinely drove (the car was registered to his wife). The court told the police they had ten days to install the device within the District.
On the 11th day, in a parking lot in Maryland, the police attached the GPS device to Mr. Jones' Jeep. Over the course of the next month the police obtained more than 2,000 pages of tracking data they used to put Mr. Jones with some really bad dudes who dealt cocaine.
Mr. Jones was subsequently indicted for his role in the conspiracy. His first trial ended in a hung jury. Los federales then obtained a second indictment. Mr. Jones wasn't so lucky at his second trial - he was convicted and sentenced to life in prison.
On appeal he argued that the installation of the GPS device constituted an unlawful search and seizure. The appellate court said "yes" and "no." The court held that installing a GPS device on a car was not the equivalent of a search - based upon the Katz test of whether the owner had a reasonable expectation in privacy as to his movements on a public roads. But the court did rule that the data obtained while the car was parked in the couple's garage or driveway did violated the Katz test.
In U.S. v. Jones, 565 US _____ (2012), the U.S. Supreme Court held that the attachment of the GPS device did constitute a search as law enforcement personnel, in effect, trespassed upon Mr. Jones' property in placing the device on the undercarriage of his car. Justice Scalia took a trip in his wayback machine and held that the Fourth Amendment was designed to protect the citizenry from trespass by the state. He wrote that Katz did not supplant the concept of physical trespass as the test to determine whether something was a search - but that it was an addition to the analysis.
Of course that doesn't explain why it's okay for the police to look through your trash can while it sits on your driveway waiting to be taken away by the sanitation engineers. It also doesn't jibe with allowing the police to wander up to a garage and look in the windows - or to look in the open windows of a house. In making those determinations, the Supremes looked at Katz and then looked away from the Bill of Rights.
In her concurrence, Justice Sotomayor castigated Justice Scalia for taking a narrow approach to the Fourth Amendment. Justice Sotomayor would rather use the Katz analysis for determining whether a search took place. In her view, today's technologies have taken us beyond the question of whether the police trespassed on someone's property. She also raised the question of whether we waive our reasonable expectation of privacy when we disclose private information to a third party (just think about your smartphone's GPS or the information you type in to register for certain websites).
Justice Alito was also concerned that the concept of trespass was passe and that it led to inconsistent outcomes depending on the surveillance methods used by the police. He also pointed out Justice Scalia's opinion failed to address the installation of tracking devices by car manufacturers such as GM's OnStar or Lo-Jack.
Justice Alito also questioned whether a motorist had a reasonable expectation of privacy regarding the movement of his car in public. He didn't seem to have too much problem with what the government did in Mr. Jones' case, but he said at some point such monitoring would raise questions. For Justice Alito, attaching the device to the Jeep wasn't the problem, the problem was the amount of time the device was allowed to transmit.
What we have here is the so-called conservative bloc of the Court ruling against the use of warrantless GPS tracking by the police to be unconstitutional based on 18th century common law trespass while the so-called liberal bloc arguing that the installation of the unit was unconstitutional because it violated Mr. Jones' reasonable expectation of privacy due to the length of time the device was transmitting. Would we have had a different decision had the device only been installed for a week, ten days, two weeks?
From my point of view, the concept of trespass should be the starting point for any Fourth Amendment analysis - with the Katz analysis used to determine if an intrusion into one's privacy not contemplated by the Founding Fathers constitutes a search. Relying on one without the other makes little sense. Left unsaid is how the Court plans to reconcile the holding in Jones with prior decisions ignoring the tort of trespass upon property.
For more analysis, please see:
"Supreme Court strikes down GPS tracking device, raises more questions in the process," Liberty and Justice for Y'all (Jan. 23, 2012)
"Reactions to Jones v. U.S.: the government fared much better than everyone realizes," SCOTUSblog (Jan. 23, 2012)