If you read the headlines this week about the Supreme Court's decision in its GPS surveillance case, you might be forgiven for thinking the Justices rang a bell for the expansion of civil liberties and privacy rights into digital territory.
Now it is true, the Court ran up the score, 9-0, in deciding against the government.
But the Justices were split over the legal rationale that should apply.
Three agreed with Justice Scalia, that the police, by surreptitiously placing a tracking device on a car outside the parameters of a judicially issued warrant, had "trespassed" on the property rights of the suspect. Scalia's reasoning relied heavily on an opinion written in 1765 by an English lord.
Three others sided with Justice Alito, who found it absurd to be asking how the Framers of the Constitution would have applied English property law to the remote harvesting of electronic signals. For Alito, the better (if imperfect) framework for analysis would have been found in more recent jurisprudence, which requires a court to weigh "reasonable expectations of privacy."
Justice Sotomayor, expressing more concern than her colleagues that existing legal precedent may not be up to the job of protecting privacy and civil liberties as mobile social networking habits become normative, found that the best thing to do with the case at hand was to agree with Scalia and Alito both. (Pending development of a suitable framework, she might say, any and every legal theory that gets you there in the meantime will have to do.)
You might ask, does the lack of a unified, coherent legal theory in this case really matter?
If you are a police chief, and you want to place a GPS device on a suspect's private vehicle without his express permission, then, arguably, no, the wrangling among the Justices is for you an academic matter. You know you need a warrant. Your GPS device, to paraphrase Alito's mocking analogy for Scalia's views, is like a tiny 18th Century constable who, having trespassed and hidden himself somewhere unseen in your oversized, horse-drawn coach, goes without food and water for weeks at a time in order to monitor your public outings.
But if you are an official with the Department of Homeland Security, asking Ford if you might tap into the GPS reporting capability built into the latest makes and models of car, then, yes, the lack of a consistent legal theory makes a difference to you, and provides choices. That is to say, you may or may not need the warrant. Under Scalia's standard, there would be no trespass. The suspect property, the car (or cars), would have included the GPS capability when the owner(s) first took possession. You need not touch or even approach the car.
Similarly, were you a government agent amassing a history of Foursquare checkins in order to compile a profile of an individual, you would probably not be concerned with tresspass. At the same time, if you skip the warrant, you run the risk that a court will find a "reasonable expectation of privacy" to protect the Foursquare checkins.
Alito feels that societal norms of privacy are better measured and codified by legislators. Sotomayor, on the other hand, is more adventurous, willing to float the exceptional idea that privacy and secrecy might be de-coupled. That is to say, Sotomayor feels it should be possible for certain information, depending on purpose or context, to remain legally protected, notwithstanding that it may be publicly accessible online or through technical means.
Appellate lawyers and Court watchers will tell you the Justices do this all the time. That is, they often decide cases on narrow and abstruse grounds, pushing the law forward as grudgingly as possible.
Such caution may be one of the few remaining factors of stability left in what now passes for American politics. But it's also a reminder to not expect too much of United States v. Jones. The lower courts will likely be wrestling with location tracking for some time.
Pictured: a constable who is too big, a carriage that is too small. (Flickr photo, George Eastman House.)