Supreme Court Rules That GPS Tracking Is A Search, But That’s About All

The Supreme Court issued a somewhat muddled ruling on GPS tracking today.

In a unanimous ruling, although a divided opinion, the Supreme Court ruled today that police cannot place a GPS tracking device on a suspects vehicle without first obtaining a warrant:

WASHINGTON — The Supreme Court on Monday unanimously ruled that the police violated the Constitution when they placed a Global Positioning System tracking device on a suspect’s car and monitored its movements for 28 days.

But the justices divided 5-to-4 on the rationale for the decision, with the majority saying that the problem was the placement of the device on private property. That ruling avoided many difficult questions, including how to treat information gathered from devices installed by the manufacturer and how to treat information held by third parties like cellphone companies.

Walter Dellinger, a lawyer for the defendant in the case and a former acting United States solicitor general, said the decision “is a signal event in Fourth Amendment history.”

“Law enforcement is now on notice,” he said, “that almost any use of G.P.S. electronic surveillance of a citizen’s movement will be legally questionable unless a warrant is obtained in advance.”

Though the ruling was limited to physical intrusions, the opinions in the case collectively suggested that a majority of the justices are prepared to apply broad Fourth Amendment privacy principles unrelated to such intrusions to an array of modern technologies, including video surveillance in public places, automatic toll collection systems on highways, devices that allow motorists to signal for roadside assistance and records kept by online merchants.

The case decided Monday, United States v. Jones, No. 10-1259, concerned Antoine Jones, who was the owner of a Washington nightclub when the police came to suspect him of being part of a cocaine-selling operation. They placed a tracking device on his Jeep Grand Cherokee without a valid warrant, tracked his movements for a month and used the evidence they gathered to convict him of conspiring to sell cocaine. He was sentenced to life in prison.

The United States Court of Appeals for the District of Columbia Circuit overturned his conviction, saying the sheer amount of information that had been collected violated the Fourth Amendment, which bars unreasonable searches.

The Supreme Court affirmed that decision, but on a different ground. “We hold that the government’s installation of a G.P.S. device on a target’s vehicle, and its use of that device to monitor the vehicle’s movements, constitutes a ‘search,’ ” Justice Antonin Scalia wrote for the majority. Chief Justice John G. Roberts Jr. and Justices Anthony M. Kennedy, Clarence Thomas and Sonia Sotomayor joined the majority opinion.

“It is important to be clear about what occurred in this case,” Justice Scalia went on. “The government physically occupied private property for the purpose of obtaining information. We have no doubt that such a physical intrusion would have been considered a ‘search’ within the meaning of the Fourth Amendment when it was adopted.”

In a concurrence for four justices, Justice Samuel A. Alito Jr. faulted the majority for trying to apply 18th-century legal concepts to 21st-century technologies. What should matter, he said, is the contemporary reasonable expectation of privacy.

“The use of longer term G.P.S. monitoring in investigations of most offenses,” he wrote, “impinges on expectations of privacy.” Justices Ruth Bader Ginsburg, Stephen G. Breyer and Elena Kagan joined the concurrence.

“We need not identify with precision the point at which the tracking of this vehicle became a search, for the line was surely crossed before the 4-week mark,” Justice Alito wrote. “Other cases may present more difficult questions.”

Lyle Denniston tries to make some sense of what the Court actually ruled today, because the existence of multiple concurrences with different legal theories makes the blanket statement that the Court found that the use of GPS tracking without a warrant is unconstitutional isn’t really correct:

Given the complexity of the voting pattern, and what the votes actually supported or failed to support, it nonetheless was clear that the Court was unanimous in one respect.  It upheld the result — but no more than the result — of a D.C. Circuit Court ruling that Jones’ Fourth Amendment rights had been violated.

Justice Department lawyers, trying to salvage their case in the Supreme Court, had argued that the electronic monitoring of Jones — even if it was a search — did not violate the Fourth Amendment because the search was based upon “reasonable suspicion, and indeed probable cause, to believe that [Jones] was a leader in a large-scale cocaine distribution conspiracy.”  Justice Scalia said the Court would not consider that argument, since it was not raised in the lower courts and the D.C. Circuit did not deal with it.  “We consider the argument forfeited,” Scalia wrote.  That meant, in practice, that Jones’ convicted was overturned, as the D.C. Circuit had ruled.

Because Scalia made mention of that alternative argument, however, it appeared likely that federal prosecutors will attempt to use it in other cases involving the use of the GPS, when the investigators had not obtained a warrant.   Some caution might be in order, though, because Justice Sotomayor’s vote was necessary to make even that part of the Scalia opinion a majority-supported result, and her separate opinion might be read to raise some doubt about her enthusiasm for that argument.

Sotomayor interpreted the Court’s ruling as a narrow one, saying that it was limited to a conclusion that “the government’s physical intrusion on Jones’ Jeep” was a search under the Fourth Amendment.  But she also noted that she agreed with the separate Alito opinion that the use of GPS technology over a prolonged period of monitoring will impinge — in at least some cases — on an individual’s constitutionally protected “expectation of privacy.”


Justice Alito’s concurring opinion, representing the views of himself and three other Justices, challenged the Scalia opinion as “unwise” for relying — in an originalist sense — about what constituted a “trespass” that invaded privacy at the time the Fourth Amendment was added to the Constitution in 1791 as part of the Bill of Rights.  The Founding generation, Alito wrote, could not have imagined GPS technology.  So, he argued, the ruling in this case should turn on the question of whether individuals have a “reasonable expectation of privacy” that could be compromised by the use of such devices.

There were two qualifications in the Alito opinion’s embrace of that approach.   Such privacy would be intruded upon, he wrote, if there were “longer term GPS monitoring,” and that would be true for “most offenses” that were under investigation.   Those two apparent limitations mean, in practice, that short-term GPS monitoring might not intrude on Fourth Amendment privacy, and police and federal agents’ investigation of some crimes with such a device might not, either.

The Court, in other words. did not go nearly as far as the three judge panel of the D.C. Circuit Court of Appeals from which this case had come, which held that the act of placing the GPS device on the Defendant’s care without a warrant was, in and of itself, unconstitutional, or the position that Judge Alex Kozinski took in a case that was before the 9th Circuit Court of Appeals several years ago. Most importantly, though, it’s worth noting that the Court did not hold today that a warrant is required to place a GPS tracking device on a Defendant’s vehicle. Instead what we seem to have gotten is a ruling that doing so constitutes is a “search” under the Fourth Amendment. Whether it’s a search that requires a warrant is a question that will have to be left for another case.

What this means, of course, is that it will take further cases to decide this issue completely, but it strikes me that Justice Alito is correct when he argues in his concurrence (joined by Justices Kennedy, Ginsburg, Breyer, and Kagan) that the Court erred significantly when it tried to turn this into an issue of trespass instead of looking to the Fourth Amendment itself:

In the pre-computer age, the greatest protections of privacy were neither constitutional nor statutory, but practical. Traditional surveillance for any extended period of time was difficult and costly and therefore rarely undertaken. The surveillance at issue in this case—constant monitoring of the location of a vehicle for four weeks—would have required a large team of agents, multiplevehicles, and perhaps aerial assistance.10 Only an investigation of unusual importance could have justified such an expenditure of law enforcement resources. Devices like the one used in the present case, however, make long-term monitoring relatively easy and cheap. In  circumstances involving dramatic technological change, the best solutionto privacy concerns may be legislative. See, e.g., Kerr, 102 Mich. L. Rev., at 805-806. A legislative body is well situated to gauge changing public attitudes, to draw detailed lines, and to balance privacy and public safety in a comprehensive way.

To date, however, Congress and most States have not enacted statutes regulating the use of GPS tracking technology for law enforcement purposes. 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 aparticular case involved a degree of intrusion that a reasonable person would not have anticipated.

Under this approach, relatively short-term monitoringof a person’s movements on public streets accords withexpectations of privacy that our society has recognizedas reasonable. See Knotts, 460 U. S., at 281-282. But the use of longer term GPS monitoring in investigations ofmost offenses impinges on expectations of privacy. For such offenses, society’s expectation has been that lawenforcement agents and others would not—and indeed, inthe main, simply could not—secretly monitor and catalogue every single movement of an individual’s car for a very long period. In this case, for four weeks, law enforcement agents tracked every movement that respondent made in the vehicle he was driving. We need not identify with precision the point at which the tracking of this vehicle became a search, for the line was surelycrossed before the 4-week mark. Other cases may present more difficult questions. But where uncertainty exists with respect to whether a certain period of GPS surveillance is long enough to constitute a Fourth Amendmentsearch, the police may always seek a warrant

Alito raises a good point in bringing up the fact that there ought to be legislative action here, because there are plenty of situations where tracking like this can be accomplished without the police having to do what they did in this case. For example, should it be permissible for law enforcement to be able to access the GPS tracking data emitted by a suspect’s cell phone, or the GPS system in their car, or the monitor the signal emitted by their electronic toll device (i.e. EZ-Pass)? Under the majority analysis, none of these would constitute a “search” because none of them involve a trespass. However, could it not be said that we have a reasonable expectation of privacy in this kind of data, or that there ought to be a law forbidding that information from being shared with law enforcement without a Court order or a search warrant? As Alito said, we have reached the point where twenty-four hour monitoring is technologically possible, and it’s only become easier as technology advances. On some level, the Courts are not the best avenue to deal with these questions because they can only deal with matters on a case-by-case basis and each particular search is dependent on the facts of the particular case, as we learned today. If we don’t get a handle on this issue soon, we may find that it’s too late to control the information that we, knowingly and unknowingly, share with the government whether we like it or not.

Here’s the opinion:

United States v. Jones


FILED UNDER: Law and the Courts, Policing, Science & Technology, US Politics, , , , , , , , , , , , , , ,
Doug Mataconis
About Doug Mataconis
Doug Mataconis held a B.A. in Political Science from Rutgers University and J.D. from George Mason University School of Law. He joined the staff of OTB in May 2010 and contributed a staggering 16,483 posts before his retirement in January 2020. He passed far too young in July 2021.


  1. sam says:

    “In a concurrence for four justices, Justice Samuel A. Alito Jr. faulted the majority for trying to apply 18th-century legal concepts to 21st-century technologies. ”

    No originalist he.

  2. Tsar Nicholas says:

    Sammy was a great prosecutor and has become even a better judge. That concurrence is much better reasoned than the majority opinion.

    Although truth be told I wouldn’t have had a problem with the cops monitoring that miscreant for a month or so. Caveat criminal as far as I’m concerned. Granted, indefinite and undefined GPS monitoring obviously would be a problem, but tracking a guy for 28 days doesn’t seem the least bit unreasonable to me, especially when the cops had grounds to be suspicious of the man.

  3. legion says:

    @Tsar Nicholas: So, you don’t have a problem with cops blatantly violating citizens’ Constitutional rights, as long as they only abuse ‘miscreants’ who aren’t you. That’s mighty white of you, TN. In case you’ve forgotten every single thing you ever got out of Civics class, “cops being suspicious” != “guilty”. If they have valid suspicions, they ought to be able to convince a judge to give them the warrant… THAT’S WHY WARRANTS EXIST – to hold cops & prosecutors to a reasonable standard of suspicion prior to authorizing an invasion of privacy. “Presumed innocent…” – remember that phrase?

  4. Hey Norm says:

    I wonder if it’s permissable to put a tracking device on a corporation?

  5. Ben says:

    I disagree that it’s difficult to parse what the opinions are here.

    All nine justices said that police cannot attach a GPS to a car and monitor it without a warrant, regardless of the theory you use to invalidate it.

    Five them (the four joined with Alito, plus Sotomayor) think that any sort of long-term GPS monitoring by any means without a warrant is unconstitutional. They don’t specifically say how long it has to be, but they hint that it’s only long enough to give them time to get a warrant.

    “But where uncertainty exists with respect to whether a certain period of GPS surveillance is long enough to constitute a Fourth Amendment search, the police may always seek a warrant.”

    One of them (Sotomayor) seems to think that ANY sort of GPS monitoring by any means without a warrant is unconstitutional, and seems to want to completely overturn the third-party doctrine in privacy law.

    “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. ”

    But she doesn’t go into detail on it, because this case gives her a more obvious out, aka the trespass onto the defendant’s car.

  6. @Ben:

    Ben I think it is more accurate to say that under the circumstances of this case the Court found that the use of the tracking device in this case without a warrant was impermissible. As the article and the majority opinion both note, the Government attempted to raise in their arguments to the Supreme Court the theory that the search was supported by reasonable suspicion and/or probable cause to believe that Jones was the leader of a drug gang. Under such a theory, the use of the tracking device would have theoretically been justified even without a warrant.

    The Court held that because this argument had not been raised in the Court of Appeals, or indeed at the District Court level, it was waived on appeal and the Court would not consider it.

    I refer you to the brief note from Orin Kerr at The Volokh Conspiracy entitled “What Jones Does Not Hold

    As for the rest of the arguments in the concurrences, they are a guide to how the Court might rule in future cases, but not law in any sense of the word

  7. PD Shaw says:

    I’d say seven days is sufficient time to use GPS tracking on reasonable suspicion; after that it doesn’t seem to be inconvenient to get a warrant and the information obtained in the initial seven days should be provided and can be used to tailor the tracking if necessary.

    I guess two things bother me about the GPS tracking. First, is that the GPS will continue to track into people’s private homes. That may not be the most useful part of GPS tracking, but technically the home is at the heart of Fourth Amend. protections. Second, the driver can switch and it may be one thing to track a criminal suspect, but if you end up tracking the teenage daughter and her boyfriend, the reason for the search is not being furthered.

    OTOH, Alito’s concerns about the cheapness of technology ignores the reality that GPS is inferior in many respects. Will GPS tell you who is driving, who they met on a street corner, or what people were wearing? If the GPS observes a crime being committed will it even know?

    The big question is why doesn’t the legislature legislate in this area? Judges have no superior incite into society’s reasonable expectations of privacy.

  8. legion says:

    One thing I don’t think has been addressed, but that I think is a valid legal question, is:

    What is it about using a GPS tracking device that’s so fantastically better than detailing a cop or two to just follow the guy? I get that it might be inconvenient for the cops, but that hardly seems to balance out the de facto trespassing that has to occur to install a tracker in the first place…

  9. PD Shaw says:

    @legion:” What is it about using a GPS tracking device that’s so fantastically better than detailing a cop or two to just follow the guy?”

    I think Alito addressed this point: “The surveillance at issue in this case—constant monitoring of the location of a vehicle for four weeks—would have required a large team of agents, multiplevehicles, and perhaps aerial assistance.” I think he is claiming that constant surveilance is going to mean at least two cops per eight hour shift, a supervisor and a runner to bring food, coffee and empty the “bed pan,” and in heavy traffic you may need a copter so you don’t lose him.

    While I have my doubts about the special value of GPS, it may produce more reliable testimony if the issues pertain to a vehicle being at a certain place at a certain time. The GPS readout shows that the perp’s car is at the corner of First and Main at 12:05 a.m. every third night, not 11:05 p.m., ot 1:05 a.m. That may end up being more reliable than a beat cop stumbling through a question about how he knows his Timex wasn’t off by an hour, or that he couldn’t have dozed off.

  10. Ben says:

    @Doug Mataconis: I’ve read Volokh already today. You’re technically correct in what you say, but I don’t see how in the world a warrantless GPS tracking could be considered a “reasonable” search, since they almost never have any of the exigencies or split second decisions needed to be reasonable without a warrant. And if the government DID try to make such an argument, I think that Alito, Ginsberg, Breyer, Kagan and Sotomayor have already tipped their hand as to how they’d rule in that sort of situation.

    And I agree that almost none of that stuff is a holding, I never stated otherwise. But people have been acting like it’s hard to parse what each side’s position is. I disagree.

  11. Ben says:

    @legion: PD already said it, but GPS allows essentially free surveillance of as many people as they want forever. No need to pay guys to stay on a 24-hour stakeout anymore. GPS makes it so that police don’t have to be judicious in their use of surveillance anymore. Surely you can see that that is ripe for widespread abuse?

  12. Remember when Alito was supposed to be just a Scalia clone that would simply follow his master’s vote without question?

  13. legion says:

    @PD Shaw:
    I think widespread abuse is _exactly_ the problem. Let me put it like this – we have a right to privacy (Scalia notwithstanding) & to avoid unreasonable search & seizure. With the proper justification, cops can get a legal writ to violate/override that right. I’m not complaining – that’s how the system is built. IANAL, but I don’t see how GPS’ “additional precision” is important enough to override those rights without requiring the same level of justification for a warrant. I just wasn’t sure if that particular argument had been raised and, per PD’s quote, it appears Alito thought about the benefits & decided they weren’t worth the abrogation (at least in this case).

  14. PD Shaw says:

    @Ben: “Surely you can see that that is ripe for widespread abuse?”

    Not really. I can see how others would disagree, but I think James Joyner had a recent post about how the national security agencies are drowning in information. It wouldn’t take much effort, if you include online databases and GPS technology, for law enforcement to drown. And most local police department do not have the FBI/ Homeland Security technology to understand and digest widespread use of GPS technology. It would become noise.

  15. PD Shaw says:

    My last comment probably answers my earlier question, why isn’t their legislation. If people don’t believe warrantless GPS tracking won’t result in widespread abuse, they won’t push their legislators to legislate in this area. So which is it?

  16. legion says:

    @PD Shaw: It would become noise when attempting to use it in actual law enforcement operations. It would become abused as cops realize they can use it to harass anyone they want, with no oversight or consequence. There is no reason both of these outcomes are not equally likely. And either of these reasons are good enough not to do it.

  17. Racehorse says:

    In the case of sex offenders and other violent criminals, having a tracking device on their car should be part of their parol rules.
    The real problem with crime today are the soft-on-crime judges who keep releasing the same violent offenders and run revolving door, kangaroo courts. We need judges who are fair but firm and are not afraid to start throwing keys away.

  18. mattb says:

    Really great insights @PD, in particular noting the problem of other people driving the car. However, there are a couple points I disagree on:

    I think that Alito’s issue ties directly into your realization that “[GPS] may produce more reliable testimony if the issues pertain to a vehicle being at a certain place at a certain time.” This is the critical “promise” of GPS — that being an instrument versus a fallible human — it’s limitations will be largely ignored in the face of its ability to unbiasedly tell “the truth.”

    This ties into the question of information overload. It seems to me that it’s a mistake to compare law enforcement and intelligence work in these cases. Especially since, from my understand, Law Enforcement is largely concerned with dealing with ongoing criminal activity and it’s aftermath, where as intelligence is focused on preventing the activity in the first place. That means that the later needs to deal with a far more open ended data set.

    While there are still a lot of potential data sources in tracking potential criminal activity, it seems to me that (for better or worse) it’s a far more “closed” system and that means that increases the potential use for algorithmic investigation.