Professor Orin Kerr recently had a very interesting short commentary regarding GPS devices in the Volokh Conspiracy. http://www.volokh.com/  He wrote,

 In a recent district court case, United States v. Ortiz (E.D. Pa. July 20, 2012), the court rejected the government’s argument that the automobile exception permits placing a GPS device on a car with probable cause. According to the court, the automobile exception only applies to justify a search inside the car based on probable cause to believe there is evidence inside the car. That can’t apply to allow a warrantless installation of a GPS device, the court ruled. Placing a GPS device on the exterior car doesn’t intrude into the car and can’t collect evidence inside, so the automobile exception can’t apply.

Assume the Ortiz decision is right, and that placing a GPS device on a car requires a warrant. Here’s my question: How should judges draft the warrant to comply with the Fourth Amendment? The Fourth Amendment states that no warrants shall issue without probable cause, and it demands that that warrants must “particularly describ[e] the place to be searched, and the persons or things to be seized.” How should a judge make sure these three requirements are satisfied? Let’s take each of the three issues in turn.

First, what is probable cause in this setting? In the case of a warrant for evidence, the relevant kind of probable cause is probable cause that evidence exists inside the place to be searched that will be collected by the search. But if the installation of a GPS device does not obtain evidence in the car, then presumably this standard doesn’t apply. My question is, what replaces it? Is it probable cause to believe that the driver has engaged in a crime? Probable cause to believe that the location of the car will itself be evidence? Probable cause of something else?

Second, what is the “place” that is searched? Is it the exterior surface of the car? The car generally? The location of the car when the GPS is installed? The location of the car over the course of the time it is installed, wherever that may be?

Third, what is the “thing” to be seized by the warrant? The GPS device doesn’t enter the car to take anything, which according to Ortiz disables the automobile exception. So what exactly does the installation of the device “seize”? Is it information about the location of the car, whatever that may be? Something else? And finally, if you think that information about the location of the car is either the place to be searched or the thing to be seized, how do you describe that with particularity?