In October, the Third Circuit Court of Appeals became the highest federal court to decide that police must first have a search warrant before they can install a GPS tracking device on a vehicle. That decision came roughly a year after the U.S. Supreme Court decided that installing a GPS tracking device on a vehicle constitutes a “search” under the Fourth Amendment (which protects us from unreasonable searches and seizures). When evidence is obtained in violation of the Fourth Amendment, the usual remedy is suppression—i.e. the prosecution can’t use it in court. This is known as the exclusionary rule a/k/a the “fruit of the poisonous tree” doctrine.
Using, as an example, the the Third Circuit’s recent decision that requires police to have a warrant to use GPS tracking devices, any GPS evidence that was obtained without a warrant should be suppressed, because of the exclusionary rule. But federal prosecutors have asked the Third Circuit to reconsider its decision en banc. This means that the court hears the case again, but instead of a the traditional three-judge panel, all of the judges of the court (currently 24) will decide the case together. En banc hearings are somewhat rare; it’s like being one step away from SCOTUS review. Prosecutors are hoping that, sitting en banc, the Third Circuit will decide that the illegally obtained GPS evidence shouldn’t be thrown out because at the time that the officers acted, search warrants were not a prerequisite to using GPS technology. This is known as the “good faith” exception to the exclusionary rule.
Since the Reagan administration, SCOTUS has been chipping away at the reach of the exclusionary rule. In cases such as Illinois v. Gates, and Nix v. Williams, SCOTUS began carving out significant exceptions to the rule. There are currently four exceptions to the rule; if one of the exceptions applies, then the prosecution is free to introduce evidence at trial in spite of the fact that the defendant’s Fourth Amendment rights may have been violated in procuring that evidence. The so-called “good faith” exception to the exclusionary rule came out of the 1984 case U.S. v. Leon, which held that evidence obtained as the result of a faulty search warrant is still admissible, so long as the officers executing the warrant had a good-faith belief that the warrant was valid.
GPS technology has been available to consumers for about a decade, but the laws governing the use of the technology are still in their infancy. The 24 judges of the U.S. Court of Appeals for the Third Circuit now get to decide whether police acted reasonably in tracking suspects with GPS devices despite the fact that there was no search warrant requirement at the time they did it.