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United States v. Jones (Amicus Brief)

The Brennan Center filed an amicus brief arguing that the prolonged, warrantless use of GPS tracking devices to monitor a suspect’s behavior is unconstitutional.

Published: October 3, 2011

In United States v. Jones, federal agents attached a GPS device without a valid warrant to a vehicle owned by Antoine Jones, a suspected drug dealer, to track his movement for a 28-day period. On August 6, 2010, the D.C. Circuit Court of Appeals overturned the conviction of Mr. Jones by holding that such “prolonged” warrantless tracking violated the Fourth Amendment.

The D.C. Circuit denied rehearing en banc and the Supreme Court granted the petition for a writ of certiorari on June 27, 2011, to revisit the Fourth Amendment jurisprudence established by United States v. Knotts, 460 U.S. 276 (1983) and United States v. Karo, 468 U.S. 705 (1984) in light of technological advancements. The Brennan Center, along with the National Association of Criminal Defense Lawyers, the First Amendment Lawyers Association, the District of Columbia Association of Criminal Defense Lawyers, the New York State Association of Criminal Defense Lawyers, and the Ohio Association of Criminal Defense Lawyers, filed an amicus brief in support of Mr. Jones. Our brief emphasized the unacceptable burden on constitutional rights imposed by warrantless GPS surveillance and the minimally burdensome warrant application process. Oral argument is scheduled for November 8, 2011.


In Knotts, the Supreme Court held that the warrantless use of a simple “beeper”-style homing device does not violate the Fourth Amendment because a “person traveling in an automobile on public thoroughfare has no reasonable expectation of privacy in his movements.” In Karo, the Court limited its holding in Knotts and found that use of the device to track movements on private property may violate the Fourth Amendment.

At issue in Jones is whether the use of advanced GPS technology to remotely monitor an individual’s every move – both in public and in private – over a prolonged period of time falls outside the rule in Knotts and should be considered a “search” for Fourth Amendment purposes. The D.C. Circuit distinguished the discrete, single-trip surveillance addressed in Knotts from the wholesale monitoring of one’s movements over the course of a month. The court concluded that Mr. Jones had a reasonable expectation of privacy in his travels because “the whole of a person’s movement over the course of a month is not actually exposed to the public” and because “prolonged surveillance reveals types of information not revealed by short-term surveillance.” Three other circuits — United States v. Garcia, 474 F.3d 994 (7th Cir. 2007), United States v. Marquez, 605 F.3d 604 (8th Cir. 2010), and United States v. Pineda-Moreno, 591 F.3d 1212 (9th Cir. 2010) — have held that warrantless GPS tracking does not violate the Fourth Amendment, but none contemplated the privacy issues caused by “prolonged” used of the device.

Summary of Brennan Center’s Amicus Argument:

The Brennan Center emphasized that the prolonged, surreptitious use of GPS tracking devices places a significant burden on the First Amendment right to association by revealing lawful and constitutionally-protected associational relationships and activities. Such surveillance “reveals the habits and patterns that mark the distinction between a day in the life and a way of life,” United States v. Maynard, 615 F.3d 544, 562 (D.C. Cir. 2010), and can reveal an individual’s church-going habits or political activities as effectively as a “requirement that adherents of particular religious faiths or political parties wear identifying armbands.” NAACP v. Alabama, 357 U.S. 449, 462 (1958). The brief contrasted this burden with a streamlined warrant application process that permits law enforcement in thirty-five jurisdictions to apply for warrants remotely, minimizing the risk of significant investigative delay. 

The Brennan Center also argued that the Court should reject the government’s reliance on the automobile exception, observing that the rationale for the exception — the mobility of vehicles and the attendant risk that evidence will be lost or destroyed — is inapplicable to GPS tracking. It is a vehicle’s very mobility that creates evidence in the GPS context.

The Brennan Center therefore urged the Court to affirm the D.C. Circuit’s ruling and find that the First and Fourth Amendments demand a warrant for the prolonged use of GPS tracking devices.