Can police attach a GPS tracker to your car, or is that an invasion of your privacy? On Monday, the U.S. Supreme Court, in United States v. Jones, ruled unanimously that doing so is a search, meaning that it must pass muster under the Fourth Amendment to the U.S. Constitution. This ruling may put a crimp in the use of this popular law-enforcement technique, but what’s really interesting is that it also may signal the court’s willingness to overhaul how it thinks about what constitutes a trespass on your privacy.
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Justice Sonia Sotomayor, who joined the majority opinion, also wrote a separate opinion saying that future cases involving GPS data obtained, for example, from car manufacturers’ location services might raise Fourth Amendment issues. Fourth Amendment law bars unreasonable searches, and Sotomayor wrote that the notion of what constitutes an unreasonable search may change with technology. People may disclose a list of search terms to a search engine, but that doesn’t mean that tracking years of a person’s Web history can’t be construed as a search on the part of the government.
In a separate concurring opinion, four justices—Alito, Ginsburg, Breyer, and Kagan—criticized the majority’s approach as unnecessarily limited by “18th century” views of property. Noting that there are many services such as cellphone tracking, toll-road records, and modern cars’ onboard data recorders that allow cars to be tracked without trespassing, these justices suggested the need for a broader focus on privacy issues. In this they, like Justice Sotomayor, seem sympathetic to the D.C. Circuit’s suggestion that when the government collects a lot of bits of data about you, it’s the aggregate of the data—the mosaic that it represents about you—that determines whether there is a search, regardless of the status of any particular bit.
