Tied Up In Knotts? GPS Technology and the Fourth Amendment

Judicial and scholarly assessment of emerging technology seems poised to drive the Fourth Amendment down one of three paths. The first would simply relegate the amendment to a footnote in history books by limiting its reach to harms that the framers specifically envisioned. A modified version of this first approach would dispense with expansive constitutional notions of privacy and replace them with legislative fixes. A third path offers the amendment continued vitality but requires the U.S. Supreme Court to overhaul its Fourth Amendment analysis. Fortunately, a fourth alternative is available to cabin emerging technologies within the existing doctrinal framework. Analysis of satellite-based tracking illustrates this last approach. The Global Positioning System (GPS) allows law enforcement officials to monitor an individual’s precise movements for weeks or months at a time. GPS technology not only is substantially different than anything the Court has previously considered, but also is a substantial threat to fundamental notions of privacy. By illustrating how, with only minor tweaking, existing Fourth Amendment law can effectively rein in intrusive applications of this one emerging technology, this Article begins to construct an analytical framework that can be applied more broadly to future technological enhancements. This Article begins by reviewing the science and capabilities of GPS-enhanced surveillance. It concludes that satellite-based tracking is a powerful investigative tool that enables authorities to monitor the movements (both indoors and out) of an unlimited number of people for weeks or months at a time. This Article then examines the Court’s historical treatment of technologically enhanced surveillance, and shows that the intrusiveness of an emerging technology is critical to its constitutional treatment. Considering the intrusiveness of GPS-enhanced tracking, this Article concludes that the unfettered use of such surveillance is inimical to fundamental Fourth Amendment principles. The most defensible treatment of GPS tracking under the existing analytical framework is that it is a search and, as such, must be preauthorized by a warrant issued only upon probable cause