On Tuesday July 20th, the Wisconsin Supreme Court sidestepped the question of whether there are any constitutional limits on police use of global positioning system devices to track people in their cars. Instead, the Court decided that a court order obtained by the police in the case of State v. Sveum satisfied the warrant requirement of the Fourth Amendment to the U.S. Constitution and the Wisconsin Constitution.

Although the Court did not decide whether a warrant is required, its ruling has the effect of overturning the Court of Appeals’ prior decision, which held that placement of and tracking with GPS devices was not “search or seizure,” and thus did not require a warrant from a judge or even that the placement and tracking be “reasonable.”

“The Court’s decision leaves open the core question of whether there are any constitutional limits to prevent the police from misusing such powerful technology to invade the privacy of innocent people,” said Catherine Crump, a lawyer with the American Civil Liberties Union, who submitted a friend-of-thecourt brief along with the ACLU of Wisconsin and the Electronic Frontier Foundation.
“The Court’s decision underlines the need for the legislature to put common-sense limits on use of GPS to prevent police officers with personal grudges or elected sheriffs with political axes to grind from placing GPS units on enemies’ vehicles to see what meetings they attend, what night spots they frequent and what churches they do – or do not – attend,” said Chris Ahmuty, Executive Director of the ACLU of Wisconsin. “Except in rare emergencies, law enforcement should have to show a judge they have a reasonable law-enforcement basis for tracking someone before they start.”

Lawyers on the friend-of-the-court brief include Amelia Bizzaro of Henak Law Office in Milwaukee, Crump of the national ACLU, Jennifer Granick of the EFF, and Larry Dupuis of the ACLU of Wisconsin. G. Michael Halfenger of Foley & Lardner argued the case before the Supreme Court on behalf of the amici. Madison Attorney Dean Strang, of Hurley, Burish & Stanton, represented Sveum.