Golden Gate University Law Review


Caitlin Emmett


In Pineda-Moreno, the Ninth Circuit held that prolonged police monitoring of a defendant’s precise location through the use of GPS transmitters did not constitute a search. In so holding, the Ninth Circuit relied on the Supreme Court decision in United States v. Knotts. Knotts held that “[a] person traveling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another.” Prior to the Ninth Circuit’s decision in Pineda-Moreno, most federal appellate courts interpreted Knotts to hold that location tracking outside the home is analogous to physical surveillance and therefore does not constitute a search under the Fourth Amendment. Since Pineda-Moreno, however, other courts have disagreed with the Ninth Circuit and have held that prolonged GPS monitoring of a defendant’s movements does constitute a search.

Part I of this Note presents the facts and procedural history of United States v. Pineda-Moreno, followed by a discussion of relevant Fourth Amendment jurisprudence, highlighting the Supreme Court’s public-exposure doctrine as described in United States v. Knotts. Part II argues that the Ninth Circuit based its decision in Pineda-Moreno on the precise issue the Supreme Court declined to decide in Knotts: whether prolonged twenty-four-hour electronic surveillance of an individual constitutes a search. In Part III, this Note goes on to analyze how the Ninth Circuit’s misinterpretation of the Knotts holding compelled it to prematurely reject Pineda-Moreno’s Fourth Amendment claim without analyzing whether he had a justifiable expectation of privacy. Part IV concludes that law enforcement’s use of GPS technology to monitor Pineda-Moreno’s movements over the course of four months constituted a search because it violated his reasonable expectation of privacy. In Part V, this Note proposes a practical two-step analysis that balances the Supreme Court’s public-exposure doctrine with the privacy interest at stake when the government utilizes advanced technology, like GPS tracking, to conduct comprehensive surveillance of an individual.