On Nov. 8, 2011, the U.S. Supreme Court will hear argument in United States v. Jones, to determine whether the government violates the Fourth Amendment when it affixes a Global Positioning System (GPS) tracking device to a person’s car and monitors its movements on public streets for four weeks without a warrant.
In determining whether a search occurred, two views of an individual’s expectation of privacy are at odds:
The D.C. Circuit held that the totality of Jones’s movements was not exposed to the public for two reasons:
- Unlike movements during a single journey, the whole of a person’s movements over the course of a month is not actually exposed to the public because the likelihood anyone will observe all those movements is effectively nil.
- The whole of movements is not exposed constructively even though each individual movement is exposed, because that whole reveals more — sometimes a great deal more — than does the sum of its parts.
Under this “mosaic” theory, the D.C. Circuit held that Jones had a reasonable expectation of privacy in the totality of his month-long pattern of movements. Thus, the government’s tracking of those movements constituted a search conducted without a warrant. Therefore, the D.C. Circuit reversed Jones’s conviction.