Last year, we wrote about a (somewhat surprising, given similar rulings elsewhere) ruling by the appeals court for DC, saying that, while law enforcement could use a GPS device to track where you go on a trip, doing long-term, always-on monitoring went beyond
the "reasonable expectation" of privacy, and was a 4th Amendment violation. This week, the Supreme Court heard the appeal on that case
, and wondered whether or not such 24/7 monitoring was reasonable. The government's argument is simply that when you're traveling in public, it's public, and so there's no expectation of privacy. But, it sounds like the Justices recognize a rather problematic slippery slope developing around this argument:
This argument seemed to alarm several of the justices. "If you win this case then there is nothing to prevent the police or the government from monitoring 24 hours a day the public movement of every citizen of the United States," Justice Breyer said. "And no one, at least very rarely, sends human beings to follow people 24 hours a day. That occasionally happens. But with the machines, you can. So if you win, you suddenly produce what sounds like 1984."
"This case does not involve 24-hour surveillance of every citizen of the United States," Dreeben countered. "It involves following one suspected drug dealer as to whom there was very strong suspicion." But he wasn't able to explain how pervasive surveillance would have to get before it became constitutionally problematic.
Chief Justice Roberts asked if the government's theory would allow the police to install tracking devices on the cars of the members of the Supreme Court. Dreeben said it would. He suggested that legislatures might want to place limits on such surveillance, but argued that it didn't raise any constitutional concerns.
Justice Kennedy asked whether the government's theory would allow the installation of a GPS tracking device on a suspect's overcoat. Again, Dreeben argued that it would, provided that it only report information about the suspect's movements in public places.
I also have to agree with Tim Lee, who wrote the Ars Technica post linked and quoted above, in noting that the lawyer for the guy who was surveilled, Antoine Jones, seemed to focus on a rather weak point in his argument. Rather than focusing on the problem that the appeals court noted -- this "mosaic theory" that the sum total of this 24/7 surveillance violated the 4th Amendment -- Jones' lawyer focused on the question of trespassing in installing the GPS device, something that seems kind of meaningless when you consider that most such tracking can now be done remotely via mobile phones/satellites, without a direct device attached to a car.