Today the U.S. Court of Appeals for the Ninth Circuit issued a disappointing but fortunately narrow decision in a case involving warrantless tracking of a vehicle with a GPS device. The three-judge panel refused to exclude GPS tracking evidence under what’s known as the “good faith” exception, ruling that when the tracking took place, law enforcement agents reasonably relied on binding circuit court precedent in concluding that no warrant was necessary. The tracking happened before the Supreme Court issued its decision in United States v. Jones that GPS device tracking triggers Fourth Amendment protections.

In the case, United States v. Pineda-Moreno, law enforcement agents attached GPS tracking devices to Mr. Pineda-Moreno’s vehicle. They did not get a warrant, and the Ninth Circuit initially ruled they didn’t need one because of its view that the Fourth Amendment provides no protections against warrantless GPS tracking.

While Mr. Pineda-Moreno’s case was still winding its way through the court system, however, the Supreme Court issued its landmark decision in Jones. The justices did not weigh in on whether a probable cause warrant is necessary whenever the government wants to engage in GPS tracking of vehicles, or whether it is sufficient for a law enforcement agent to reasonably believe that a search will turn up evidence of wrongdoing.

In this most recent round of briefing in the Ninth Circuit, Mr. Pineda-Moreno argued that, after Jones, the GPS tracking evidence in his case should be thrown out, because a warrant is the constitutional minimum (the ACLU filed an amicus brief in his support). Today the Ninth Circuit disagreed, but on narrow grounds that limit the decision’s relevance for the rest of us. It held that, given the state of Ninth Circuit case law at the time Mr. Pineda-Moreno was tracked, the agents reasonably relied on binding Ninth Circuit precedent in believing it was lawful to attach a GPS device to a car without a warrant. And given that reasonable reliance, the Court held that the evidence gathered by GPS tracking could be used against Mr. Pineda-Moreno.

This decision is bad news for Mr. Pineda-Moreno and other defendants in the Ninth Circuit who were tracked before the Supreme Court issued its decision in Jones but whose cases are still working their way through the court system.

It’s important to note what the court did not do. It did not rule on whether, going forward, the government needs a warrant based on probable cause to attach a GPS device to a car. Given the privacy-invasive nature of location tracking, a warrant is the constitutionally-required minimum. This decision also does not affect defendants in other parts of the country whose cases are outside the Ninth Circuit’s jurisdiction. Nevertheless, it’s crucial that Americans’ privacy is maintained in the face of ever more powerful government surveillance tools.

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