(CN) - Police need a warrant before using GPS to track a suspect, the Supreme Court ruled Monday, with the justices disagreeing about how to weigh these "searches" in the digital age.
Though the FBI had obtained a warrant for such tracking of nightclub owner Antoine Jones in 2004, they failed to carry it out correctly.
Washington, D.C., police and the FBI had been investigating Jones for about a year on suspected drug trafficking.
Based on surveillance of Jones' club and a wiretap on his cellphone, a D.C. federal judge gave the government a warrant to install an electronic tracking device on the Jeep Grand Cherokee registered to Jones' wife. The warrant specified that the device should be installed in the district in 10 days.
On the 11th day, agents installed the Global Positioning System device as the Jeep was parked in a public Maryland parking lot.
After tracking Jones for about a month, the government indicted him on several cocaine and crack conspiracy charges. GPS data that the government submitted as evidence linked Jones to a stash house that contained $850,000 in cash, 97 kg of cocaine, and 1 kg of cocaine base.
Jones was sentenced to life in prison, but the D.C. Circuit overturned the conviction in 2010 because it found that the GPS tracking constituted a violation of Jones' Fourth Amendment rights.
GPS tracking, instead of human surveillance, enables 24-hour surveillance at nominal cost, allows police to track vehicles in private places and public roads, and enables the simultaneous surveillance of an unlimited number of people, according to court papers.
The D.C. Circuit decision followed a brief from the American Civil Liberties Union and the Electronic Frontier Foundation, which argued that the use of GPS is not covered by the U.S. Supreme Court's nearly 30-year-old beeper findings. In the 1983 decision of United States v. Knotts, the high court permitted the use of legally installed radio beepers to help police physically follow a vehicle on public roads. But the court made it clear that the ruling did not control "dragnet-type law enforcement practices" or technical intrusion into private places.
The Supreme Court affirmed the vacated conviction on Monday.
"By attaching the device to the Jeep, officers encroached on a protected area," according to the majority opinion authored by Justice Antonin Scalia.
In a concurring opinion, Justice Sonia Sotomayor laments that the trespass test employed by her colleagues in the majority will offer "little guidance" as officers more commonly rely on "electronic or other novel modes of surveillance that do not depend upon a physical invasion on property."
"More fundamentally, it may be necessary to reconsider the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties," she wrote. "This approach is ill suited to the digital age, in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks. People disclose the phone numbers that they dial or text to their cellular providers; the URLs that they visit and the e-mail addresses with which they correspond to their Internet service providers; and the books, groceries, and medications they purchase to online retailers. ... I for one doubt that 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."
Sotomayor had joined in Scalia's opinion with Chief Justice John Roberts, Justice Anthony Kennedy and Justice Clarence Thomas, but the remaining justices filed an opinion concurring in the judgment.
Calling the majority's holding "unwise," Justice Samuel Alito also remarked that "it strains the language of the Fourth Amendment; it has little if any support in current Fourth Amendment case law; and it is highly artificial."
Alito said the court should have determined whether the "long-term monitoring" of the movements of Jones' Jeep violated his reasonable expectations of privacy.
"To date ... Congress and most states have not enacted statutes regulating the use of GPS tracking technology for law enforcement purposes," Alito wrote. "The best that we can do in this case is to apply existing Fourth Amendment doctrine and to ask whether the use of GPS tracking in a particular case involved a degree of intrusion that a reasonable person would not have anticipated.
"Under this approach, relatively short-term monitoring of a person's movements on public streets accords with expectations of privacy that our society has recognized as reasonable. But the use of longer term GPS monitoring in investigations of most offenses impinges on expectations of privacy."
The majority had little patience for Alito's reference to long- and short-term monitoring.
"That introduces yet another novelty into our jurisprudence," Scalia wrote. "There is no precedent for the proposition that whether a search has occurred depends on the nature of the crime being investigated. And even accepting that novelty, it remains unexplained why a 4-week investigation is 'surely' too long and why a drug-trafficking conspiracy involving substantial amounts of cash and narcotics is not an 'extraordinary offens[e]' which may permit longer observation. What of a 2-day monitoring of a suspected purveyor of stolen electronics? Or of a 6-month monitoring of a suspected terrorist?"
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