U.S. Supreme Court Extends Constitution to GPS Tracking

In a landmark decision [pdf], the U.S. Supreme Court has ruled unanimously that government agents violated the Constitution when they tracked a suspect for 28 days using a GPS device installed without a warrant.

The case, US v. Jones, was right out of the television show The Wire: The government suspected a nightclub owner of being part of a drug operation. Investigators installed a GPS tracking device on the undercarriage of an SUV used by the suspect and tracked him 24/7 for nearly a month, ultimately using the evidence they obtained to convict him of conspiracy to sell cocaine.

The Justice Department argued in the Supreme Court that no one has a right of privacy while exposing themselves to observation on the public roads, even if technology makes possible a degree of surveillance that is impossible for human beings. Not a single Justice agreed.

The three opinions issued by the Justices in explaining their holding are important for several reasons.

First, the Court made it clear that it will not casually allow technology to erode the Constitutional right to privacy. The Center for Democracy & Technology (CDT), as part of a project supported by the Open Society Foundations, had submitted a brief in the case [pdf] in which we explained how GPS tracking was fundamentally different from human observation. Our brief was signed by leading technologists, including one often credited with being the inventor of GPS. Five of the Justices expressed concerns in their opinions about the range of new technologies that make possible surveillance of unprecedented intrusiveness.

Second, the Court clarified its interpretation of the Fourth Amendment’s protection against unreasonable searches and seizures. The lead opinion, written by Justice Scalia, focused on the fact that the government had physically occupied private property (even though very minimally) for the purpose of obtaining information. That alone was enough for five Justices to find that the government’s action was a “search” under the Fourth Amendment, which generally requires the government to obtain a warrant issued by a judge  before conducting a search. However, Justice Scalia made it clear that property was not the only basis of Fourth Amendment violations. Justice Scalia reaffirmed that a Fourth Amendment violation also occurs when government officers violate a person’s reasonable expectation of privacy.

Four concurring Justices, in an opinion by Justice Alito, argued that the reasonable expectation of privacy test was more suited to the computer age (while recognizing that it had its own difficulties).  These Justices felt that relatively short-term monitoring of a person’s movements on public streets accords with reasonable expectations of privacy, but that prolonged monitoring does not.

Factually, the case was limited to installation and use of a GPS device owned by the government, but Justice Alito’s opinion clearly has implications for the government’s use of data from cell phones to triangulate a person’s position. If, as the concurring Justices said, there is a reasonable expectation not to be tracked for a prolonged period of time, that expectation would seem to apply whether the tracking occurs by the government’s GPS device or by the phones, laptops and other mobile devices we carry with us every day.

Perhaps the most interesting opinion was written by Justice Sotomayor, who agreed with Justice Scalia’s property-based theory but wrote separately to emphasize that the reasonable expectation test offered an alternative basis for the Court’s bottom line. Thus, at least a majority of five Justices seem ready to hold that a warrant is normally required for prolonged location monitoring even if it does not involve the physical intrusion of a government-planted GPS device. (Justice Sotomayor suggested that even short-term monitoring may violate the reasonable expectation test, given unique attributes of GPS surveillance.)

Justice Sotomayor then went on to question the core of the government’s argument – the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties (whether by walking down the street or by browsing the Internet and disclosing the website addressing information to your ISP).  Expanding on the rationale of Justice Alito, she said she doubted whether “people would accept without complaint the warrantless disclosure to the government of a list of every Web site they had visited in the last week, or month, or year.”

This question – whether we really do surrender our expectation of privacy in the vast stores of data we disclose daily in the course of using modern technology – represents the next phase of litigation in the digital age over the constraints on government surveillance imposed by the Fourth Amendment.

For now, even with respect to cell phone tracking, the decision leaves many questions unanswered. In his opinion, Justice Alito essentially urged Congress to get involved and draft legislation drawing detailed lines.

We at the Center for Democracy & Technology agree that Congress has a major role. We have helped organize a coalition of major Internet companies, think tanks, and advocacy groups from across the political spectrum that is calling on Congress to require a warrant for cell phone tracking in most cases.

Revitalization of the Fourth Amendment must occur in both the courts and the legislature. The Supreme Court’s decision this week is a major step forward.