On November 8th the Supreme Court is to hear oral argument for the case United States v. Jones, which questions the constitutionality of warrantless GPS tracking. The blog Threat Level has asserted that this case is one of the most significant Fourth Amendment cases to be heard in a decade because it weighs “the collision of privacy, technology and the Constitution.”

The case comes from the D.C. Circuit Court of Appeals’ reversal of the defendant’s conviction of “conspiracy to distribute five kilograms or more of cocaine and 50 or more grams of cocaine base, in violation of 21 U.S.C. 841 and 21 U.S.C. 846.” Brief for the United States.  The evidence leading to the defendant’s conviction was discovered after the police installed a GPS tracking device on the defendant’s wife’s car, and his movements were tracked for over a month. Although police had originally obtained a warrant, it was valid only in the District of Columbia, and furthermore, had expired the day before the police installed the device in Maryland. As a result, the defendant argues, the installation of the GPS tracking device resulted in an unconstitutional warrantless search.

The government argues that the defendant can have no expectation of privacy in his movements from one place to another on public streets because they are in plain view, and that therefore the tracking did not constitute a search under the Fourth Amendment. The defendant, on the other hand, argues that although there may not be an expectation of privacy in his movements from one place to another, there is an expectation of privacy in the aggregate of his movements, and that therefore the warrantless GPS tracking was an unlawful search. In a 2001 case, Kyllo v. United States, the court ruled that a warrant was required in order to use thermal-imaging devices to locate marijuana-growing because the use of such technology constituted a search under the Fourth Amendment because “the government violate[d] a subjective expectation of privacy that society recognizes as reasonable.” However, in that case, the court emphasized that the home occupies a special place in our jurisprudence, and that there is an expectation of privacy in the home’s interior that society has long recognized as reasonable.  The Court again dealt with technological advances in police equipment in United States v. Knotts, in which the Court held that a tracking beacon installed in chemical container that allowed police to tail the defendant’s car for hundreds of miles was not a search under the Fourth Amendment.

The D.C. Circuit Court of Appeals agreed with the defendant’s argument, distinguishing this case from Knotts on the basis that there is a sizeable difference between tailing a person for a few hundred miles and putting a person under twenty-four hour surveillance. The court held that there is indeed an expectation of privacy in the aggregate of one’s movements that current technology has enabled the police to monitor with relative ease.

As George Washington University law professor Jeffrey Rosen noted in an interview:

[W]hat [the Court is] now confronted pretty squarely in this case is the question of whether we really should have expectation of privacy in the face of proliferating cutting edge technology or not. That has less to do with the reality on the ground, how many devices there are out there, than to what the justices think people should expect in free society. Is there some degree of anonymity we need in order to live spontaneous and free lives? That’s what the court’s going to have to engage.

It is clear that this case presents not only a novel question regarding GPS technology specifically, but more broadly, a question about the extent to which the government may use rapidly-developing technology that has the potential to seriously limit a person’s reasonable expectation of privacy without a warrant.  If the Court affirms the Circuit Court’s reversal, Catherine Crump, a staff attorney with the American Civil Liberties Union, believes the decision will represent another step towards protecting privacy “in the face of technological advances.” A reversal, however, has equally important consequences, as such an outcome could greatly broaden the government’s authority to monitor citizens’ lives through the use of technology. The potential for the curtailment of privacy posed by such warrantless tracking could be mitigated by a bill, the Geolocational Privacy and Surveillance Act (“GPS Act”), that Sens. Ron Wyden (D-Ore.) and Mark Kirk (R-Ill.) recently advocated in a press conference that would require law enforcement officials to obtain a warrant before using GPS technology to track suspects. Whether such legislation is politically feasible has yet to be seen, but it does indicate the growing concern that technological advances have begun to infringe on citizens’ privacy rights.