It seems likely that new sorts of surveillance that police and prosecutors want to use are running close to the edge of privacy guarantees in the constitution:
Charlie Savage, Judges Divided Over Growing GPS Surveillance - NYTimes.com
“Often what we have to do with the march of technology is realize that the difference in quantity and speed can actually amount to significantly more invasive practices, “ said Paul Ohm, a University of Colorado law professor and former federal computer-crimes prosecutor. “It’s like you keep turning the volume knob and it becomes something different, not the same thing just a little louder.”
Last week, such calls seemed to be answered by an ideologically diverse panel on the United States Court of Appeals for the District of Columbia. It overturned a drug trafficking conviction because the evidence against the defendant included tracking data from a GPS receiver that the police hid under his sport utility vehicle without a warrant. The device essentially recorded his whereabouts 24 hours a day for four weeks.
Traditionally, courts have held that the Fourth Amendment does not cover the trailing of a suspect because people have no expectation of privacy for actions exposed to public view.
But the appeals court argued that people expect their overall movements to be private because different strangers see only isolated moments and a police department’s surveillance resources are limited. GPS technology, by allowing police departments to inexpensively track someone’s comings and goings, changes that equation, it said.
“Prolonged surveillance reveals types of information not revealed by short-term surveillance, such as what a person does repeatedly, what he does not do, and what he does ensemble,” wrote Judge Douglas Ginsburg.
“A person who knows all of another’s travels can deduce whether he is a weekly churchgoer, a heavy drinker, a regular at the gym, an unfaithful husband, an outpatient receiving medical treatment, an associate of particular individual or political groups — and not just one such fact about a person, but all such facts.”
Supreme Court review of the decision seems likely. It contradicted decisions in three similar GPS-related cases by appellate panels in Chicago, St. Louis and San Francisco.
In 2007, for example, Judge Richard Posner argued that “following a car on a public street” is “unequivocally not a search within the meaning” of the Fourth Amendment. While acknowledging that “technological progress poses a threat to privacy by enabling an extent of surveillance that in earlier times would have been prohibitively expensive,” he concluded that using a GPS device to investigate a suspect crossed no constitutional line.
The Fourth Amendment “cannot sensibly be read to mean that police shall be no more efficient in the 21st century than they were in the 18th,” he wrote. “There is a tradeoff between security and privacy, and often it favors security.”
But the tradeoffs that could favor security — like being able to barge into people’s homes unannounced — are specifically blocked by the constitution. Therefore we will have to reestablish limits to hold back an increasing lack of privacy and sovereignty over personal information, like geolocation.