A couple of highlights: In rejecting the argument that the car's movements are observable by the public and therefore the owner has no reasonable expectation of privacy in them:
Two considerations persuade us the information the police discovered in this case — the totality of Jones‘s movements over the course of a month — was not exposed to the public: First, unlike one‘s movements during a single journey, the whole of one‘s movements over the course of a month is not actually exposed to the public because the likelihood anyone will observe all those movements is effectively nil. Second, the whole of one‘s movements is not exposed constructively even though each individual movement is exposed, because that whole reveals more — sometimes a great deal more — than does the sum of its parts.
...In considering whether something is "exposed" to the public as that term was used in Katz we ask not what another person can physically and may lawfully do but rather what a reasonable person expects another might actually do.
....we hold the whole of a person‘s movements over the course of a month is not actually exposed to the public because the likelihood a stranger would observe all those movements is not just remote, it is essentially nil. It is one thing for a passerby to observe or even to follow someone during a single journey as he goes to the market or returns home from work. It is another thing entirely for that stranger to pick up the scent again the next day and the day after that, week in and week out, dogging his prey until he has identified all the places, people, amusements, and chores that make up that person‘s hitherto private routine.
In another section, the Court aptly notes:
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. These types of information can each reveal more about a person than does any individual trip viewed in isolation.
Repeated visits to a church, a gym, a bar, or a bookie tell a story not told by any single visit, as does one‘s not visiting any of these places over the course of a month. The sequence of a person‘s movements can reveal still more; a single trip to a gynecologist‘s office tells little about a woman, but that trip followed a few weeks later by a visit to a baby supply store tells a different story.
A person who knows all of another‘s travels can deduce whether he is a weekly church goer, a heavy drinker, a regular at the gym, an unfaithful husband, an outpatient receiving medical treatment, an associate of particular individuals or political groups — and not just one such fact about a person, but all such facts.
The Court finds we do have a reasonable expectation of privacy in our movements over a prolonged time:
...Society recognizes Jones‘s expectation of privacy in his movements over the course of a month as reasonable, and the use of the GPS device to monitor those movements defeated that reasonable expectation. As we have discussed, prolonged GPS monitoring reveals an intimate picture of the subject‘s life that he expects no one to have — short perhaps of his spouse. The intrusion such monitoring makes into the subject‘s private affairs stands in stark contrast to the relatively brief intrusion at issue in Knotts; indeed it exceeds the intrusions occasioned by every police practice the Supreme Court has deemed a search under Katz....
The Court also noted how important the GPS tracking evidence was, when combined with the defendant's cell-phone records, in proving the conspiracy, quoting the prosecutor's closing argument.
The GPS data were essential to the Government‘s case. By combining them with Jones‘s cell-phone records the Government was able to paint a picture of Jones‘s movements that made credible the allegation that he was involved in drug trafficking....In his closing statement the Government attorney summarized this way the inference he was asking the jury to draw:
...[W]hen there is a conversation with Bermea and [Jones] says, I‘m coming to see you, or I‘ll be there in ten minutes, and within a while ... the GPS shows that that vehicle is in Potomac Drive, how does that all fit together? Well it fits together exactly as you know. That the defendant is going to 9508 Potomac Drive, and there‘s no reason anyone goes there other than drug activity.
The failure to get a warrant, the court says, is not harmless error. Bottom line:
Jones‘s conviction is reversed because it was obtained with evidence procured in violation of the Fourth Amendment.
GPS tracking, like cell site locator information, reveals a lot about you. It can tell the cops if you went to an AA meeting, visited an abortion clinic or an X-rated movie theater. I hope the judges in the Third Circuit, which are soon to issue the first federal appellate decision on whether the government needs a search warrant to obtain cell site locator data, are reading today's opinion.
