The Volokh Conspiracy

The Massachusetts Supreme Judicial Court has asked for amici help in two pending cases about the Fourth Amendment and GPS surveillance:

In these cases involving co-defendants, the issue presented, among others, is whether an affidavit demonstrated sufficient probable cause in support of an application for a warrant secretly to attach a GPS device to a motor vehicle and to monitor tracking information; whether a passenger has standing to challenge the evidence seized as a result of such monitoring; whether a passenger in a vehicle to which a GPS device is attached is either “seized” or “searched” to the same extent as the driver or the vehicle itself.

On the first question, probable cause, I gather there is a preliminary issue of whether a warrant or probable cause is required to install the GPS device. There is litigation pending on that issue in the federal courts — it’s a difficult issue, in my view — although I don’t know if the issue is also being litigated in the Massachusetts case. Assuming that already has been answered in the affirmative or (unfortunately) has been conceded away, the question becomes what kind of probable cause is deemed sufficient. In the case of a Fourth Amendment search, the ordinary kind of probable cause is probable cause to believe that there is particularly described evidence to be seized inside the particularly described place to be searched. I don’t know how this is supposed to work with a GPS warrant, though. In the case of a GPS search, the government isn’t actually looking to search inside the car for evidence. The car is the place where the GPS is installed, and under Jones it is the “place” where the search occurs. But the information sought is outside of that place, not inside it: The government wants to know where the car will go, not what is inside the car. Perhaps the constitutional standard should be probable cause to believe that the location of the car will be evidence of crime. But if so, I don’t know how you draft the warrant. Is the place to be searched the car, and the evidence to be seized just something abstract like “information about the location of the car”? I’m not sure. That’s not a terrible starting point if you need to cram it into existing doctrine, although it’s not a very clean fit.

On the second question, standing, I think the proper scope of standing depends on what ground(s) the Court uses to conclude that the use of a GPS device was a search. If the SJC is only relying on the Jones trespass rationale, then under Jones I would think the Court needs to consider whether the driver and passenger each individually have sufficient property rights (either as owner or bailee) to challenge the search. See Jones, footnote 2. If the SJC is relying on a reasonable expectation of privacy approach but not the mosaic theory to say that the use of the GPS device is a search — which seems unlikely, but I suppose it’s still theoretically possible — then I would think the framework of Rakas v. Illinois, 439 U.S. 128 (1978), still applies. Finally, if the SJC is relying on the mosaic theory of the Jones concurrences to say that the use of the GPS device is a search, then there are lots of complex questions of standing and remedy that the Court has to answer. In my article, The Mosaic Theory of the Fourth Amendment, 111 Mich. L. Rev. 311 (2012), I flag some of those questions that need to be answered if a court adopts the mosaic approach. An excerpt:

If the exclusionary rule generally applies to mosaic search violations, courts will need to determine its scope. The first challenge is identifying who has standing to challenge a mosaic search. Fourth Amendment rights are personal, and individuals can invoke a remedy only if their own rights have been violated. The Fourth Amendment standing inquiry arises as an application of the reasonable expectation of privacy test. Every defendant must establish that his or her own reasonable expectation of privacy was violated to merit a ruling suppressing the evidence.

Standing raises difficult challenges for the mosaic theory because conduct that creates a mosaic may involve monitoring different people at different times to different degrees. Consider the facts of a recent district court case, United States v. Luna-Santillanes. Three conspirators ran a heroin trafficking enterprise and shared three cars. Different drivers drove the three different cars at different times. Investigators installed GPS devices on all three cars and used the GPS devices to track the movements of the three defendants. The first car was monitored for two months; the second car was monitored for what the court called “a few” days; and the third car was monitored for only two days.

Assuming that the collective monitoring of the three cars constituted a search, who has standing to challenge it? Do all three defendants have standing because their location was monitored as part of a broader mosaic? Or must the standing inquiry look to each individual and consider whether the monitoring of that particular defendant was enough to constitute its own mosaic? Or perhaps the standing inquiry should operate on a car-by-car basis, limiting standing to primary drivers or passengers of particular cars? If the exclusionary rule applies to mosaic searches, courts will need to develop answers to these questions.

[Next] consider whether the exclusionary rule applies to the entire mosaic or only some part of it. To simplify matters, let’s use the prior assumption that seven days of GPS monitoring crosses the line to become a search. If the police monitor a GPS device for ten days, must the entire ten days of monitoring be suppressed? Or should courts only suppress the last three days of monitoring data that occurred after the search line was crossed? Further, imagine the police learn on day two of the ongoing surveillance that the suspect committed a crime. Should the evidence from day two be suppressed because it was part of the mosaic triggered after seven days, even though the collection of that evidence was not a search when it occurred? Or is the evidence from day two an inevitable discovery because it would have been discovered if the monitoring had stopped before the amount of monitoring crossed the mosaic threshold?

A related issue arises when investigators use surveillance to locate targets at a particular moment rather than to develop a picture of their lives over time. Consider a recent case involving a GPS device attached to a car used to transport heroin. Investigators used GPS tracking to find the car. After finding the car, officers conducted a pretextual traffic stop based on a traffic violation, asked for and obtained consent to search the car, and then retrieved two kilograms of heroin inside. Assuming the GPS device was used long enough to cross the threshold of a search, should the heroin be suppressed as a fruit of the poisonous mosaic search? Or does the exclusionary rule not apply because the stop was the product of a short-term use of the GPS device rather than a broader mosaic?

I recently blogged about United States v. Skinner, the new Sixth Circuit decision concluding that the Fourth Amendment does not protect location information obtained from a cell phone. Skinner has been getting a lot of attention in the blogosphere, in part because the facts are so vague, so decided to take a closer look at the case to see what I could learn about the facts in dispute.

Here’s what I learned. First, here’s the first of the two court orders that the government obtained to compel the phone company to reveal location information. It’s one of the “hybrid” orders that DOJ has tried to use (or at least was using as of 2006, the date of the order) that combines several statutory authorities at once — pen trap, 2703(d), subpoena, etc. Putting aside the open question of the legality of such hybrid orders under statutory laws, the important part for Fourth Amendment purposes is what the court order allows the government to do in terms of location information. The order requires the phone company to provide the government with the following:

(This image may not be sizing correctly for some browsers.  If you’re not seeing well, you can view it here.)  As you can see, the order authorizes the government to get both cell-site and GPS information from the phone. So which did the government use when it “pinged” the phone? It’s somewhat hard to tell, because the magistrate judge’s Report and Recommendation refers to both GPS and cell-site and doesn’t focus much on the distinction. At the same time, the fact section of the magistrate judge’s Report and Recommendation refers primarily to GPS information, not cell-site data. Here’s the critical section, available at United States v. Skinner, 2007 WL 1556596 (E.D.Tenn. 2007):

Agent Lewis was given authorization to ping [FN9] the phone and ascertain its GPS location. He testified that he knew the phone had a GPS device installed in it based on the type of phones that allow minutes to be loaded onto them. Only a few models of telephones are available to those who opt not to subscribe to a wireless service but instead buy a phone which requires minutes to be loaded. After contacting the phone carrier, Agent Lewis learned the specifications for this phone and that it had GPS capabilities.

FN9. “Pinging” a cell phone garners the GPS or triangulation information. [Doc. 71-Tr. 74]. Technically, the phone company does the actual pinging, but the phone company will ping a phone at the government’s ordered request. [Doc. 71-Tr. 75]]

Once Agent Lewis pinged the phone, he discovered that it was in North Carolina. Agent Lewis testified that he immediately realized he had misunderstood previous intercepts of West’s conversations. He now realized that the “James Westwood” phone was the phone that West used to call Big Foot, not the phone in Big Foot’s possession used to call West. To ascertain the number of the phone being used by Big Foot, Agent Lewis called the phone company to get the toll records of all numbers dialed by the “James Westwood” phone. There were several calls, but all were to the help-line and to one other number, (520) 869-6820. The (520) 869-6820 number was registered to “Tim Johnson” and, based on the process of elimination, the agents knew it was the phone being used by Big Foot.

On July 13, 2007, Knoxville agents sought a new order, authorizing the agents to track the “Tim Johnson” phone. Though the actual affiant was Agent Davis, Agent Lewis testified they were working “hand in hand” throughout the investigation and application process. [Doc. 71-Tr. 61]. Agent Lewis also testified that he always relies, and relied in this specific instance, on the Assistant United States Attorneys to provide the correct legal bases to support the applications and affidavits. The agents obtained the order sought.

Acting on the authority granted by the Court, the agents obtained GPS information from the phone company. From this information, the agents learned that the “Tim Johnson” phone was in Arizona. From a wire intercept, they learned that the last load of marijuana had been transferred to the RV on July 13. They also learned that Big Foot was not going to begin his cross-country journey until July 14. The agents believed that, once loaded, the caravan would transport the marijuana to Tennessee, but through a wire intercept they learned that Big Foot was actually going to take the marijuana to his home. Because the agents did not know the exact location of Big Foot’s residence, and thus far did not know Big Foot’s identity, they decided their best course of action was to locate the vehicle and apprehend it on its way east.

The agents did not have anyone following the vehicles and conducting visual surveillance. Therefore, the Knoxville agents watched where the phone was located via GPS tracking with the goal of ascertaining the location of the couriers, Big Foot and his son. They learned that the phone was traveling on an interstate, I-40, on July 15 and moving east across Texas. While watching the phone travel, the officers intercepted a phone call. Agent Lewis testified that at 10:30 P.M. there was a call between, he believed, West and Apodaca, “and Apodaca was wanting to know the progress of the load of marijuana and where it was. And West made the statement that, ‘I just spoke to him and he told me that he’s going to be driving for another couple of hours before he rests.’ ” [Doc. 71-Tr. 50]. At that point, the agents realized the courier would be stationary soon and began to narrow their focus to which Texas office they needed to work with to apprehend the courier. The agents determined that the Lubbock, Texas DEA office would be the closest to where the RV was likely to stop for the night.

At around 2 A.M., the Knoxville agents noticed that an identical GPS reading was appearing. They realized that what West had said earlier was coming true; Big Foot was taking a rest for at least some period of time. Using the latitude and longitude data provided from the telephone company, the agents determined that the vehicle was located at a truck stop near Abilene, Texas.

As I read this, it seems to me that the location monitoring was obtained by ordering the cell-phone provider to contact the phone and have the phone send on its GPS coordinates, not by obtaining cell-site location information that the cell provider was collecting in the ordinary course of business. If that’s right, I think it is still correct that the monitoring did not violate a reasonable expectation of privacy under United States v. Knotts, the radio beeper case, at least so long as the monitoring only revealed the location of the phone on public streets (which appears to be the case). At the same time, I think the legality of the monitoring has to be justified under Knotts as limited by Karo rather than under the broader third party doctrine cases like Smith v. Maryland that the Sixth Circuit at times invoked in support of its opinion.

For more, here’s the government’s appellate brief in Skinner; here are the defense opening briefs and reply brief.

The various opinions in United States v. Jones (aka the GPS case) raise tons of fascinating new questions for Fourth Amendment law. I explore some of those issues in a forthcoming article, The Mosaic Theory of the Fourth Amendment, which will appear in the Michigan Law Review and which I hope to post an early draft of soon. In the meantime, here are three cases just from the last week or so on the implications of Jones.

1) United States v. Anderson-Bagshaw, 2012 WL 774964 (N.D.Ohio, March 8, 2012). This case considers whether Jones applies to video surveillance. The defendant was claiming disability benefits while running an alpaca farm. The government installed a camera on a telephone pole adjacent to the defendant’s property and recorded video of the property continuously for 24 days. The video was streamed over the Internet to a federal agent, who watched the video stream 3-5 hours a day and used some of it for evidence at trial. The use of the camera did not trespass on the suspect’s property. Held by District Judge Gwin: The mosaic theory does not apply, because the majority in Jones did not adopt the mosaic theory.

If the majority [in Jones] had adopted a mosaic theory condemning uninterrupted GPS surveillance, and further extended that theory to non-trespassory surveillance, then perhaps a substantial question of law might have been presented as to the constitutionality of the continuously streamed footage. Perhaps then the constitutionality of the 24–day surveillance would be a close question, or one that could go either way. But no such theory was adopted, and the pole camera footage remains soundly within the purview of caselaw reviewed in the Court’s denial of Bagshaw’s motion to suppress and motion to reconsider, under which authority this is not a close question.

2) State v. Zahn, — N.W.2d —-, 2012 WL 862707 (S.D. March 14, 2012). Under facts essentially identical to those in Jones, the Supreme Court of South Dakota concludes that the facts amount to a search both under the Jones trespass theory and also under the mosaic theory, essentially adopting both the majority and concurring opinions in Jones. On the latter point, the Court states:

When the use of a GPS device enables police to gather a wealth of highly-detailed information about an individual’s life over an extended period of time, its use violates an expectation of privacy that society is prepared to recognize as reasonable. The use of a GPS device to monitor Zahn’s activities for twenty-six days was therefore a Fourth Amendment search under the Katz “reasonable expectation of privacy” test.

The Court also concludes that a warrant is required for GPS surveillance, although its analysis is cursory. The opinion is not entirely clear whether the Court is concluding that a warrant is required for a Jones trespass search, a Katz mosaic search, or both, although the one sentence seems to be suggesting that it is focused on a warrant requirement for a mosaic search. Here’s the Court’s full analysis:

The United States Supreme Court has carved out a number of “well-delineated exceptions” to the warrant requirement. Katz, 389 U.S. at 357, 88 S.Ct. at 514. The Court has found that the presence of exigent circumstances excuses a warrantless search and that a warrantless search and seizure of an individual for the limited purpose of briefly investigating reasonably suspicious behavior is permissible. See Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968); Warden v. Hayden, 387 U.S. 294, 87 S.Ct. 1642, 18 L.Ed.2d 782 (1967). Consent searches, searches conducted incident to a valid arrest, automobile searches, and searches of items in plain view are also allowed without a warrant. None of these exceptions readily applies to the use of a GPS device to monitor an individual’s activities over an extended period of time.

Justice Zinter concurs to complain that the Court should not have addressed the mosaic theory: “Because we are deciding this case under the federal Constitution, we should not utilize a Fourth Amendment test that the majority of the Supreme Court has expressly declined to apply.”

3) United States v. Nwobi, 2012 WL 769746 (C.D. Cal. March 7, 2012). Under facts essentially identical to those of Jones, Judge King holds that the exclusionary rule does not apply because Ninth Circuit precedent from 1999 held that it was neither a search nor a seizure to install a GPS device on a car. See United States v. McIver, 186 F.3d 1119, 1126 (9th Cir.1999). Under the latest good-faith exception case, Davis v. United States, 131 S.Ct. 2419, 180 L.Ed.2d 285 (2011), the officer is deemed to have relied in good faith on McIver and the exclusionary rule does not apply.

No, concludes Judge Bennett in United States v. Graham (District of Maryland, March 1, 2012). Judge Bennett concludes that historical cell-site records are not protected because they fall under the third-party doctrine:

Like the bank records at issue in [United States v.] Miller, the historical cell site location records in this case are not the ‘private papers’ of the Defendants—instead, they are the ‘business records’ of the cellular providers. Federal law does not mandate that cellular providers create or maintain this type of data,11 and even courts that have concluded that government acquisition of cumulative cell site location records can violate the Fourth Amendment generally acknowledge that these records are ‘generated in the ordinary course of the provider‘s business.’ In re Application of the United States, 747 F. Supp. 2d 827, 841 (S.D. Tex. 2010) (Smith, Mag. J.), appeal docketed, No. 11-20554 (5th Cir. Dec. 14, 2011). Moreover, insofar as historical cell site records are created and maintained by the cellular providers, individual customers do not generally have access to those records, and could not be expected to produce them in response to a subpoena. Under the reasoning of Miller, therefore, historical cell site location records are the provider‘s business records, and are not protected by the Fourth Amendment.

. . .
Based on clear Supreme Court and Fourth Circuit precedent, this Court finds the third-party doctrine applicable to historical cell site location information. Like the bank records at issue in Miller, the telephone numbers dialed in Smith, and the subscriber information collected in Bynum, historical cell site location records are records created and kept by third parties that are voluntarily conveyed to those third parties by their customers. As part of the ordinary course of business, cellular phone companies collect information that identifies the cellular towers through which a person‘s calls are routed.

Judge Bennett also includes an extensive analysis of the concurring opinions in Jones that appear to embrace what I have called a “mosaic theory” of the Fourth Amendment. He concludes that he cannot embrace a mosaic theory in this case, however, because the theory is so different from what has come before that it should be construed narrowly until the circuit courts or Supreme Court indicate to the contrary:

[I]t appears as though a five justice majority is willing to accept the principle that government surveillance over time can implicate an individual‘s reasonable expectation of privacy. However, as will be discussed below, the factual differences between the GPS technology considered in the Jones case and the historical cell site location data in the present case lead this Court to proceed with caution in extrapolating too far from the Supreme Court‘s varied opinions in Jones. Until the Supreme Court or the United States Court of Appeals for the Fourth Circuit definitively conclude that an aggregation of surveillance records infringes a Fourth Amendment legitimate expectation of privacy, this Court must apply the facts of this case to the law as currently interpreted.

Judge Bennett ultimately concludes that the established caselaw on the third-party doctrine trumps the mosaic theory, at least for now: “unless and until the Supreme Court affirmatively revisits the third-party doctrine, the law is that a ‘person has no legitimate expectation of privacy in information he voluntarily turns over to third parties.’ Smith v. Maryland, 442 U.S. 735, 743-44 (1979) (citing, e.g., United States v. Miller, 425 U.S. 435, 443 (1976)).”

This strikes me as a pretty sensible resolution of the issue given the current state of the caselaw. Note that Judge Bennett suggests that there may be a constitutional difference between collecting prospective and historical cell-site information, so the decision is relatively narrow. Also note that the issue in Graham arises in a motion to suppress filed in a criminal case, so the case does not raise the ripeness concerns I have addressed in my amicus brief in the Fifth Circuit case that otherwise raises similar issues.

Thanks to reader Michael Wein for the pointer.

Over the last forty years, the Supreme Court has worked out a series of principles for when a defendant has standing to object to the Fourth Amendment search of someone else’s property. According to the those cases, the key issue is whether the government violated the defendant’s own reasonable expectation of privacy under the framework introduced by Justice Harlan’s concurring opinion in Katz v. United States. The owner, legitimate renter, or legitimate repeated borrower of a car generally has standing to object to a search of it. A person who steals a car or drives it in violation of a rental contract does not.

In the recent GPS decision of United States v. Jones, however, the Supreme Court introduced — or, depending on how you look at it, reintroduced — two new kinds of Fourth Amendment searches. First, the majority opinion introduced a trespass test for what is a search that supplements the Katz expectation-of-privacy test. Second, to the extent you think it proper to combine the votes of the concurring opinions and consider that an alternative holding, five Justices thought that the cumulative effect of 30 days of monitoring of the car also amounted to a search of the car because it revealed such invasive information about its public location over time.

So here’s the question: Does the standing inquiry developed over the last forty years for Katz expectation–of-privacy searches apply in the same way for Jones trespass searches and Jones long-term expectation of privacy searches? Or is the standing test different?

That isssue arose in a case handed down just a week after Jones: United States v. Hanna, 2012 WL 279435, *1+ (S.D.Fla. Jan 30, 2012) (NO. 11-20678-CR). The police suspected that four men — Hanna, Ransfer, Middleton, and Davis — were involved in a conspiracy to commmit a series of robberies.  Hanna was known to often drive the car of his co-conspirator Middleton. The police installed a GPS device without a warrant and monitored the location of the car. The combination of GPS and visual monitoring showed that Hanna and Ransfer drove together in Middleton’s car (with the GPS on it) to meet up with Middleton and Davis. This particular case involves a prosecution against Hanna and Ransfer.  The government wants to admit the GPS evidence at trial to help show the meeting occurred.

Defendants Hanna and Ransfer moved to suppress that evidence, but Magistrate Judge Edwin Torres denied the motion for lack of standing:

In United States v. Jones, the Supreme Court concluded that a “search” under the Fourth Amendment is triggered when law enforcement attaches a GPS tracking device to a vehicle and uses that device to track the vehicle’s movements. 565 U.S. ––––, No. 10–2159, 2012 WL 171117 (Jan. 23, 2012). The Government invaded a person’s effects when “[t]he Government physically occupied private property for the purpose of obtaining information.” Slip Op. at 4. Justice Scalia’s majority opinion expressly noted that Jones “was ‘the exclusive driver’ “ of the vehicle, and that if he “was not the owner he had at least the property rights of a bailee.” Id. at 3 n. 2. Jones—as the effective property owner or bailee of the vehicle—had standing to challenge an infringement on his property. Indeed, Justice Scalia emphasized that Jones “possessed the Jeep at the time the Government trespassorily inserted the information-gathering device,” id. at 9, contrasting Jones’s situation from earlier cases in which the Court had blessed the use of electronic beepers that had been placed inside packages before they were transferred to the defendant challenging their use. Id. at 9 (distinguishing Karo v. United States, 468 U.S. 705, 104 S.Ct. 3296, 82 L.Ed.2d 530 (1984), because “Karo accepted the container as it came to him, beeper and all, and was therefore not entitled to object to the beeper’s presence, even though it was used to monitor the container’s location”).

Indeed, the point of disagreement with the concurring opinion in Jones was the re-emergence of a trespass theory for Fourth Amendment searches rather than application of existing reasonable expectation of privacy doctrine. Id. at 4–6 (Alito, J., concurring). But the result of the case under the concurring opinion would have been that surreptitious long-term monitoring of the Defendant through the GPS device constituted a search because it “impinges on expectations of privacy.” Id. at 13. In that case, the driver of the vehicle had an expectation of privacy that he would not be monitored for four weeks with agents “track[ing] every movement that respondent made in the vehicle he was driving.” Id.

Under either approach recognized by Jones, an essential component of the Fourth Amendment claim requires that one’s own personal “effects” have been trespassed (e.g., one’s automobile when a GPS tracking device was secretly installed), or that one’s own expectation of privacy was impinged (e.g., one’s own movements were continuously monitored and tracked for a material period of time). That is principally where these Defendants’ attempt to benefit from the Supreme Court’s decision in Jones fails. Neither Ransfer nor Hanna was either the owner or exclusive user of the Ford Expedition. To the contrary, the record shows that members of the robbery crew consistently referred to the Expedition as co-Defendant Middleton’s truck. It is undisputed, and the Court has found, that neither Ransfer nor Hanna was in possession of the Expedition at the time that the alleged trespass (the installation and subsequent use of the tracker) occurred. It is also undisputed that Middleton owned that vehicle at all relevant times. Thus, to the extent that Jones relies upon a theory of trespass upon private property, neither Ransfer nor Hanna has standing to challenge a trespass upon property as to which they had no rights. Continue reading ‘Does Fourth Amendment Standing Work Differently for Jones Trespass Searches, Traditional Katz Searches, and Long-term Katz Searches?’ »

FoxNews.com reports that legal experts are divided on whether United States v. Jones requires a warrant to install a GPS device:

Most media reports of the Supreme Court’s decision said the court was requiring police to obtain warrants for attaching GPS devices.

But several experts argued that the court had not in fact ruled that a warrant is now required.

“The court merely held that the installation of the GPS was a Fourth Amendment ‘search,’” George Washington University Professor of Law and computer law expert Orin Kerr wrote on The Volokh Conspiracy website.

“The court declined to reach when the installation of the device is reasonable or unreasonable. So we actually don’t yet know if a warrant is required to install a GPS device; we just know that the installation of the device is a Fourth Amendment ‘search.’”

But other experts have said the court did create a warrant requirement for installing GPS devices. They point to past Supreme Court rulings that held that all Fourth Amendment searches require warrants unless the police action meets a specific and well-delineated exception.

These scholars say that because the court did not create an exception for GPS searches, those intrusions therefore require a warrant.

“Orin Kerr would probably not say that you don’t need a warrant to break down the door of someone’s house,” Priscilla Smith, who is a senior fellow at the Yale Law School Information Society Project, told NewsCore. “He would say you do need one unless one of the exceptions apply. Same is true here.”

Other scholars had views that fell somewhere in between those of Kerr and Smith.

University of Iowa Law School Professor of Law James Tomkovicz told NewsCore that the Supreme Court “dodged” the warrant issue, but said it would be very difficult to persuade courts in the future that police do not need warrants to install GPS devices on automobiles.

“It would be pretty unprecedented for the court to call it a search and then turn around and say you don’t need a warrant or you don’t even need probable cause,” Tomkovicz said.

Lawrence Muir, who teaches a cybercrimes seminar as an adjunct professor at Washington and Lee University School of Law, said that police are now generally required to obtain warrants for GPS attachments after Monday’s decision.

Two thoughts in response. First, to the extent anyone really claims that Jones ruled on whether the police must obtain warrants, the text of the opinion clearly indicates to the contrary:

The Government argues in the alternative that even if the attachment and use of the device was a search, it was reasonable—and thus lawful—under the Fourth Amendment because “officers had reasonable suspicion, and in-deed probable cause, to believe that [Jones] was a leader in a large-scale cocaine distribution conspiracy.” Brief for United States 50–51. We have no occasion to consider this argument. The Government did not raise it below, and the D.C. Circuit therefore did not address it. See 625 F.3d, at 767 (Ginsburg, Tatel, and Griffith, JJ., concurring in denial of rehearing en banc). We consider the argument forfeited. See Sprietsma v. Mercury Marine, 537 U.S. 51, 56, n. 4 (2002).

The D.C. Circuit concurring opinion referenced above notes that “because the Government did not argue the points, the court did not decide whether, absent a warrant, either reasonable suspicion or probable cause would have been sufficient to render the use of the GPS lawful[.]” Maybe I lack creativity, but I cannot see how anyone — much less an expert — can read the Supreme Court’s discussion here as a ruling that a warrant is required to install a GPS device.

Second, I’m puzzled by the claim that a warrant is obviously or very likely required for GPS surveillance because the Fourth Amendment requires warrants for home searches. The police install GPS devices on cars, not homes. Sure, the Fourth Amendment requires warrants to search homes. But the Supreme Court has always treated searches of automobiles quite differently. The unbroken rule from the first automobile case in 1925 to the present is that searching an automobile requires probable cause but does not require a warrant. This is known as the “automobile exception” to the warrant arequirement.

The Court has justified the different treatment of cars on two grounds. First, cars can be quickly moved. By the time an officer obtains a warrant to search a car, the car might be outside of the court’s jurisdiction; if the car is outside the court’s jurisdiction, the car can’t be searched either as a matter of law or fact. As the Supreme Court recognized as far back as 1925, in language that it has repeated since:

[T]he guaranty of freedom from unreasonable searches and seizures by the Fourth Amendment has been construed, practically since the beginning of Government, as recognizing a necessary difference between a search of a store, dwelling house or other structure in respect of which a proper official warrant readily may be obtained, and a search of a ship, motor boat, wagon or automobile, for contraband goods, where it is not practicable to secure a warrant because the vehicle can be quickly moved out of the locality or jurisdiction in which the warrant must be sought.

Carroll v. United States, 267 U.S. 132, 153 (1925).

The second justification for treating automobile searches differently than home searches is that while searching a car is still a search, cars are simply less private than homes.

Automobiles, unlike homes, are subjected to pervasive and continuing governmental regulation and controls, including periodic inspection and licensing requirements. As an everyday occurrence, police stop and examine vehicles when license plates or inspection stickers have expired, or if other violations, such as exhaust fumes or excessive noise, are noted, or if headlights or other safety equipment are not in proper working order.

The public is fully aware that it is accorded less privacy in its automobiles because of this compelling governmental need for regulation. Historically, individuals always [have] been on notice that movable vessels may be stopped and searched on facts giving rise to probable cause that the vehicle contains contraband, without the protection afforded by a magistrate’s prior evaluation of those facts.

In short, the pervasive schemes of regulation, which necessarily lead to reduced expectations of privacy, and the exigencies attendant to ready mobility justify searches without prior recourse to the authority of a magistrate so long as the overriding standard of probable cause is met.

California v. Carney, 471 U.S. 386 (1985) (internal quotations and citations omitted).

So let’s return to Jones. The Jones majority opinion argues that installing the device with intent to use it constitutes a search of the car. That’s the traditional set of circumstances that trigger the automobile exception. And the rationale of the automobile exception plausibly applies here, too. If the police delay to get a warrant, the car known to be in one place today might be lost tomorrow. A car in one jurisdiction today can be driven outside the court’s jurisdiction in minutes or hours. And if it is a reasonable search to break open a car’s trunk and rifle through a suspect’s private stuff without a warrant, why isn’t it a reasonable search to attach a device to the outside of a car’s frame? Isn’t the placing of the device on the outside of the car less invasive than rummaging through a suspect’s personal items stored in the locked trunk?

To be clear, I’m not arguing that the automobile exception definitely applies to the installation of a GPS device. You can make arguments that it does not.** Maybe those arguments will carry the day, maybe they won’t. But it seems mistaken to me to suggest that the relevant Fourth Amendment precedents strongly point to requiring a warrant to install a GPS device. Under the automobile exception to the warrant requirement, that’s not where the relevant precedents most naturally point.

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** For example, in his opinion concurring in the denial of rehearing en banc, Judge Ginsburg briefly suggested two reasons why the automobile exception didn’t apply. First, Jones’s car was not “readily mobile”; second, the automobile exception only applies to searches for contraband. As for the first reason, it’s hard to know why: If the motor home in Carney was deemed readily mobile, I don’t know why Jones’s car wasn’t, as well. As for the second reason, it”s true that the early cases did limit the automobile exception to contraband instead of mere evidence. But as the Sixth Circuit noted in United States v. Kemper, 503 F.2d 327 (6th Cir. 1974), this limitation reflected the “mere evidence rule” later overturned in Warden v. Hayeden (1967), and is hard to justify post-Hayden. See Kemper, 503 F.2d at 331 (“While it could initially have been said that Carroll is applicable to the search for and seizure of contraband only, the demise of the ‘mere evidence’ rule in Warden v. Hayden, 387 U.S. 294, 87 S.Ct. 1642, 18 L.Ed.2d 782 (1967), would suggest that the distinction between contraband and instrumentalities, on the one hand, and mere evidence on the other, would no longer be a valid limitation on the automobile exception.” See also Arizona v. Gant, 556 U.S. 332 (2009) (articulating the automobile exception as being that”[i]f there is probable cause to believe a vehicle contains evidence of criminal activity, [the automobile excerption] authorizes a search of any area of the vehicle in which the evidence might be found.”) (emphasis added). In my view, a better argument that the automobile exception doesn’t apply would start from the point that the kind of information revealed by GPS surveillance is not information about the inside of the car, but rather about its public location. You could then try to argue that the automobile exception should apply only when the relevant information involves the former not the latter. This isn’t an easy or obvious argument to make, but it might go somewhere.

If anything is clear from the Supreme Court’s decision last week in United States v. Jones, it’s that not very much is clear from the Supreme Court’s decision in United States v. Jones. Reading over the commentary on Jones both in the print media and on blogs, I think I’ve seen just about every reaction (at least from enthusiasts of greater privacy, from which the commentariat is almost exclusively drawn). My favorite analysis so far is this new post from Tom Goldstein. I think it’s a real gem. But it’s only one view among many as to what the case means.

Why is Jones such a puzzling decision? I think there are two major reasons. First, Justice Scalia creates a new test for Fourth Amendment searches without being fully candid that he’s doing something quite new. Trespass has long been relevant to the Fourth Amendment search inquiry, to be sure. But the Court never embraced a straight trespass test, and even in the old days deviated from it (see Boyd, McGuire, etc). So this test is new. And yet Scalia writes his opinion as if a well-established trespass test existed that he is returning to, and that returning to it is some sort of obvious step. The disjunct between Scalia’s doctrinal innovation and his apparent incredulity that anyone could find his opinion confusing makes for some very strange reading.

For example, if you want to understand the new trespass test, you mostly have to read the footnotes — especially footnotes 3 and 5, which are responses to Alito’s concurrence. Here, though, Scalia is so dismissive of Alito’s critique that it’s hard to know why Scalia sees Alito’s questions as so obviously answered. Scalia is the one who is introducing a new test; presumably he’s the one who knows what the new test will look like. But these footnotes are filled with phrases indicating tremendous certainty: “no doubt,”"quite irrelevant,” “undoubtedly occurred”, “undoutedly true, but undoubtedly irrelevant,” “similarly irrelevant,” etc. Such certainty makes it hard to know what principle Scalia is applying that makes him so certain he’s right.

The second reason Jones is so confusing is that Justice Alito spends only a single paragraph of his 14-page opinion explaining how he would resolve the Jones case. Most of his opinion is spent criticizing Scalia’s test in great detail. Alito makes some very good points in that section, I think. But we only get to how Alito would resolve the case in the middle of page 13, near the end. And in that one paragraph, Alito is surprisingly unclear as to what he is doing. Without giving the issue any analysis, Alito seems to assume that the reasonable expectation of privacy test is simply about what privacy a hypothetical reasonable person would think — a common error, as I have noted — and then he just says that this case has gone too far, in his view.

But the reader is left uncertain as to why. Is Alito embracing the DC Circuit’s novel “mosaic theory”? If so, isn’t such a revolutionary change in Fourth Amendment doctrine worth a bit of explanation? (Or does Alito not recognize the revolutionary nature of that approach?) And if the line is to be drawn, where and why? Like Justice Scalia, Alito uses a statement of judicial certainty as a substitute for analysis: “the line was surely crossed before the 4-week mark,” he says, emphasis added, with no explanation of why that is sure.

I don’t mean to be too critical of the Justices here. They’re generalists, not Fourth Amendment nerds. But I think these characteristics of the Jones opinions make the decision a Rorschach test. You can read the opinions in many different ways depending on what you want to read into them. And I think that explains why the commentary about Jones is all over the map.

I was interviewed recently by Bob Garfield of NPR’s “On the Media” about the Supreme Court’s opinions in the Jones GPS case.  The 6-minute interview has been posted here.

During the oral argument a few weeks ago in United States v. Jones, Chief Justice Roberts had some very interesting questions about the Fourth Amendment’s “reasonable expectation of privacy” test. I fear that the Chief Justice’s questions may reflect a common misunderstanding of the test. In this post, I wanted to explain the Chief’s possible error, and explain how I think the reasonable expectation of privacy test is supposed to work.

I. The Possible Misunderstanding

The questions that grabbed my attention seemed to assume that the “reasonable expectation of privacy” test asks an empirical question — that a Fourth Amendment expectation of privacy is “reasonable” when reasonable people expect privacy. Just before the relevant exchange, Deputy SG Michael Dreeben had argued that using a GPS device on the suspect’s car could not have infringed the suspect’s reasonable expectation of privacy because it only revealed the suspect’s location in public. The Chief Justice responded:

CHIEF JUSTICE ROBERTS: I give you that, that it’s in public. Does the reasonable expectation of privacy trump that fact? In other words, if we ask people, do you think it’s — it violates your right to privacy to have this kind of information acquired, and everybody says yes, is it a response that, no, that takes place in public, or it simply the reasonable expectation of privacy regardless of the fact that it takes place in public?

MR. DREEBEN: Well, something that takes place in public isn’t inherently off limits to a reasonable expectation of privacy. That’s essentially the holding of Katz. You go into a phone booth, you’re in a public; making your calls within the phone booth is subject to a reasonable expectation of privacy. But this Court, with full awareness of that holding, in Knotts and in Karo recognized that surveillance of a vehicle traveling on the public roadways doesn’t fit that description.

CHIEF JUSTICE ROBERTS: You can see, though, can’t you, that 30 years ago if you asked people does it violate your privacy to be followed by a beeper, the police following you, you might get one answer, while today if you ask people does it violate your right to privacy to know that the police can have a record of every movement you made in the past month, they might see that differently?

A similar point came up later in the same argument when counsel for Jones argued that “society does not expect” monitoring like GPS monitoring and therefore it violates a reasonable expectation of privacy. Chief Justice Roberts responded by asking how we know what people think is a violation of privacy:

CHIEF JUSTICE ROBERTS: How do we tell? I mean, I don’t know what society expects. I suppose if you ask people do you think it’s a violation of privacy for the police to do this for no reason for a month, maybe they would come out one way. If you asked the people do you think the police have to have probable cause before they monitor for 5 minutes the movements of somebody they think is going to set off a huge bomb, maybe you get a different answer.

Interestingly, Chief Justice Roberts had a similar line of questioning during the April 2010 oral argument in City of Ontario v. Quon, which raised a question (that the Court ultimately did not answer) of whether people have a reasonable expectation of privacy in text messages. Quon was a police officer who had been given a text pager by the city; he had been told that he could use the pager for personal messages but that the city would audit the messages and that he had to pay for any overage charges caused by his personal messaging. The city ultimately did audit the messages, read them, and use them to embarrass Quon, and Quon claimed that this violated his Fourth Amendment rights. Chief Justice Roberts’ questioning again went to what privacy a reasonable person might expect:

CHIEF JUSTICE ROBERTS: Well, we are dealing with Mr. Quon’s reasonable expectations, right?

MR. RICHLAND: Yes, yes.

CHIEF JUSTICE ROBERTS: And even with the written policy, he has the instructions — everybody agrees — you can use this pager for private communications.

MR. RICHLAND: That’s correct.

CHIEF JUSTICE ROBERTS: We’re not going to audit them. Right? That’s what he said. He has to pay for them. Right? Now, most things, if you’re paying for them, they’re yours. And this — it particularly covered messages off-duty. Now, can’t you sort of put all those together and say that it would be reasonable for him to assume that private messages were his business?

It’s important not to make too much of questions at oral argument, of course. Sometimes oral argument questions are designed to play devil’s advocate, or to point out problems to other Justices. But my sense from both arguments is that Chief Justice Roberts may understand the “reasonable expectation of privacy” test to pose an empirical question: The Court determines when an expectation of privacy is “reasonable” by asking whether a reasonable person would expect a privacy right in those circumstances.

I think this understanding is incorrect, although I come across it often: Indeed, I have encountered it sufficiently often that I have responded to it here before. But given that the issue keeps coming up, I wanted to explain a bit more why I don’t think it’s correct.

II. What Makes an Expectation of Privacy Reasonable?

The trick to understanding this problem is that the phrase “reasonable expectation of privacy” is a legal term of art that shouldn’t be applied literally. As the Court explained in United States v. Jacobsen, “[t]he concept of an interest in privacy that society is prepared to recognize as reasonable is, by its very nature, critically different from the mere expectation, however well justified, that certain facts will not come to the attention of the authorities.” Put another way ,a reasonable expectation of privacy is not the same as the expectation of privacy of a reasonable person. This point is clearer and less counterintuitive if we use the alternative articulation of the Katz test. The Court uses “reasonable expectation of privacy” and “legitimate expectation of privacy” interchangeably, but I think the latter term is less confusing and more revealing about what the test is and how it should be applied.

So if an expectation of privacy isn’t reasonable (or “legitimate”) when a reasonable person would have that expectation, when is it reasonable (or “legitimate”)? I think the most helpful explanation in the caselaw was authored by then-Justice Rehnquist in Rakas v. Illinois:

Obviously, however, a “legitimate” expectation of privacy. by definition. means more than a subjective expectation of not being discovered. A burglar plying his trade in a summer cabin during the off season may have a thoroughly justified subjective expectation of privacy, but it is not one which the law recognizes as “legitimate.” His presence, in the words of Jones, 362 U.S. at 362 U. S. 267, is “wrongful”; his expectation is not “one that society is prepared to recognize as reasonable.’” Katz v. United States, 389 U.S. at 389 U. S. 361 (Harlan, J., concurring). And it would, of course, be merely tautological to fall back on the notion that those expectations of privacy which are legitimate depend primarily on cases deciding exclusionary rule issues in criminal cases. Legitimation of expectations of privacy by law must have a source outside of the Fourth Amendment, either by reference to concepts of real or personal property law or to understandings that are recognized and permitted by society. One of the main rights attaching to property is the right to exclude others, see W. Blackstone, Commentaries, Book 2, ch. 1, and one who owns or lawfully possesses or controls property will, in all likelihood, have a legitimate expectation of privacy by virtue of this right to exclude.

Expectations of privacy protected by the Fourth Amendment, of course, need not be based on a common law interest in real or personal property, or on the invasion of such an interest. These ideas were rejected both in Jones, supra, and Katz, supra. But, by focusing on legitimate expectations of privacy in Fourth Amendment jurisprudence, the Court has not altogether abandoned use of property concepts in determining the presence or absence of the privacy interests protected by that Amendment. No better demonstration of this proposition exists than the decision in Alderman v. United States, 394 U. S. 165 (1969), where the Court held that an individual’s property interest in his own home was so great as to allow him to object to electronic surveillance of conversations emanating from his home, even though he himself was not a party to the conversations. On the other hand, even a property interest in premises may not be sufficient to establish a legitimate expectation of privacy with respect to particular items located on the premises or activity conducted thereon. See Katz, supra at 389 U. S. 351; Lewis v. United States, 385 U. S. 206, 385 U. S. 210 (1966); United States v. Lee, 274 U. S. 559, 274 U. S. 563 (1927); Hester v. United States, 265 U. S. 57, 265 U. S. 58-59 (1924).

Rehnquist sharpens the analysis significantly in this passage, I think. He points out that the test isn’t about empirical expectations; that it’s not just a circular question; that it has to be rooted in some outside source; and that no one outside source is dispositive. Further, Rehnquist starts off the list of possible outside sources that can make an expectation of privacy reasonable: property is one, and “understandings that are recognized and permitted by society,” whatever that may mean, is another.

Back in 2006-07, I wrote an article that went through all of the Court’s “expectation of privacy” cases and developed a comprehensive list for what sources the Court has relied on: I called the article “Four Models of Fourth Amendment Protection,” as I found four different kinds of arguments (what I called “models”) that the Court has used to justify expectations of privacy. More broadly, that article tried to explain why the Court has used the different explanations, and why no one explanation suffices: The test for what is a search has to distinguish less invasive types of law enforcement steps from more invasive types of steps, all in a world in which the facts of investigations are constantly changing and new facts are arising, and no one test seems to do that in a way that can be readily administered in a complex court system.

Of course, that doesn’t mean that reliance on the four models is ideal, although as I explain in the article, I do think it has a lot of unrecognized benefits. And as I have explained more recently, it does facilitate the needed equilibrium-adjustment in cases that involve new technologies. But at a minimum, I think this does explain why the Court does not and should not apply the “reasonable expectation of privacy” test simply by asking when a reasonable person would expect privacy.

The Justices of the Supreme Court will meet soon to offer preliminary votes in United States v. Jones, the GPS case. We don’t know what the voting alignment will look like: The votes are hard to predict. But it seems to me that there’s a substantial chance that the Court’s opinions might face a puzzling problem of figuring out which voting rule applies. I wanted to explain a bit about why I think that, and why it might matter.

Here’s the problem, at least as I see it right now. There are two issues in the Jones case, and they arise sequentially. The issue that arises first in time is whether the installation of the device is a search or seizure, and if so, whether it was a reasonable search or seizure; the issue that arises second in time is whether the use of the device after it was installed is a search or seizure, and if so, whether it was a reasonable search or seizure. Based on the argument, it was clear there was at least one vote (Scalia) for the view that installation of the device is a search. It was also clear that at least some other Justices are interested in saying that the use of the device is a search or seizure. The tricky question is, what happens if a majority of the Court concludes that somewhere in the process of installing and using the GPS there is a search or seizure, but there is no agreement as to which steps triggers the analysis or what constituties reasonableness?

To frame the issue, consider two common occurrences, each with a different voting rule. First, imagine members of a multi-member court are asked to say whether conduct in a single event is lawful. There are two different theories for why the conduct might be unlawful: Question 1 asks whether the conduct is unlawful because it violates legal theory 1, and Question 2 asks whether the conduct is unlawful because it violates legal theory 2. A majority rules that the conduct is unlawful, but there is no majority view as the reason. How do we figure out the law? We would simply tally the votes for the event. If it’s possible to group the votes into broader and narrower rationales, then the job is easy: The narrowest rationale in favor of the majority result becomes the working rule under a Marks analysis: The law is that the conduct was unlawful for the reason offered in the narrow opinion. If it’s impossible to group the votes into broader and narrower rationales, then we get a result and yet not a precedential clear rule. The conduct is deemed unlawful, but we don’t get a working rule as to why that can guide future caselaw development in the lower courts.

On the other hand, imagine that members of a multi-member court are asked to resolve the lawfulness of two independent events litigated in a single case. Question 1 asks whether the first event is lawful, and Question 2 asks whether the second event is lawful. A majority of the judges rule that one of the events is unlawful, but they disagree as to which event: For each individual event, a majority of judges concludes that the event is lawful. How do we figure out the law? We have the same principle as before: We tally the votes for each event. But the application of the principle is different, as this time there are two events instead of one. So we need to count the votes for each event individually. This ends up with a different voting rule, as now we’re considering votes per issue rather than votes as a whole. The result is that the government’s conduct is deemed legal, as there is a majority vote for lawfulness for each event.

That brings us back to Jones. As I see it, it’s not clear which voting rule applies. Are the two Questions Presented most accurately viewed as presenting two different theories about the lawfulness of a single event? Or are they most accurately viewed as presenting the lawfulness of two different events? It’s not entirely clear, as it depends how you group the events: Is installation and use one event, or two distinct events? The answer might conceivably determine whether GPS usage is legal.

To see why, imagine 3 Justices would rule for the government and say neither installation nor use is a search or seizure; 3 Justices would rule that the installation is a search or seizure but the use is not; and three Justices conclude that installation is not a search or seizure but use is. If you see use and installation as two separate events, then the government’s conduct is lawful: Each event is lawful by a 6-3 vote. But if you see installation and use as a single event, then the government’s conduct is unlawful: Again there is a 6-3 vote, but this time the 6-3 vote is for unlawfulness (albeit on two rationales).

Further, the Justices themselves can disagree on whether the installation and use are one event or two. And that can create real puzzles. To see why, imagine 7 Justices see the installation and use as two distinct events instead of one. Specifically, 3 Justices would rule for the government and say neither installation nor use is a search or seizure; 3 Justices would rule that the installation is a search or seizure but the use is not; and one Justice would rule that installation is not a search or seizure but use is. In contrast, two Justices conclude that installation and use should be viewed as a collective single event and that this one event is a search or seizure. What voting rule applies now, and what rule emerges? I’m not sure there is an answer. Now there is no one event to tally votes: There are 3 votes that installation is a search; two votes that installation and use together is a search; and one vote that installation is not a search but use is. I’m not sure what voting rule should apply given the disagreement as to what counts as an event.

Perhaps I’m just missing something obvious and there is an easy answer to these puzzles. But if there is no majority view in Jones, I would think these puzzles may need to be addressed.

I was at the Supreme Court this morning for the oral argument in United States v. Jones, the GPS case. In this post, I want to blog my reactions to the argument: I’m going to update the post as I go, so general readers can get the important stuff first at the top and then general readers can get the rest down the page.

1) My basic reaction was that the outcome was too close to call. The Justices gave both sides a very hard time, and few Justices tipped their hand. The Justices pushed Michael Dreeben (arguing for the United States) on the consequences of his argument: If the Government was right, they noted, then the government can install a GPS device on all the Justices’ cars and watch them, too, along with everybody else. They pushed Steve Leckar (arguing for Jones) on the difficulty of identifing a clear Fourth Amendment principle to distinguish visual surveillance from GPS surveillance. The votes were hard to count, but if you had to summarize a reaction of the Court as a whole, I would say that the Justices were looking to find a principle to regulate GPS surveillance but unconvinced (at least as of the argument) that there was a legal way to get there without opening up a Pandora’s Box of unsettling lots of long settled practices.

2) The Justice who most clearly showed his cards was Justice Scalia. Justice Scalia made clear that he would overrule Katz v. United States; make common law of trespass the test for what is a search; and say that the installation of the device was a search because it was a technical trespass. Even if Katz can’t be overturned, Scalia indicated, at the very least the common law of trespass should be a floor of Fourth Amendment protection: Katz should be allowed to go beyond the original Fourth Amendment but not erode it. Cf. Kyllo v. United States. At the same time, Justice Scalia made equally clear that he thought the use of the device after installation was not a Fourth Amendment problem. What is invasive and scary isn’t a search, Scalia emphasized, and the kind of line-drawing as to when use of a GPS device should be allowed is quintessentially a legislative question. So Scalia is on board for saying that installation of the device is a search, but no more. (As an aside, it’s not at all clear that the original public meaning of the Fourth Amendment operated on a common law of trespass principle. Warren Court opinions liked to describe pre-Warren Court decisions as adopting such a principle, and that has led many to believe that the Fourth Amendment underwent a transition in the 1960s from protecting property to protecting privacy. But if you go back and read the cases, that narrative — pushed most strongly by justice Brennan in Warden v. Hayden — is plainly inaccurate. The early cases usually rejected common law trespass as a principle, much as post-Katz cases do. More on that in a future post.)

3) Other justices gave a more mixed reaction to Justice Scalia’s idea of regulating the installation of the device as a search under the technical trespass doctrine. Justices Alito and Kagan seemed particularly skeptical. Both pointed out that this solution wouldn’t necessarily work in the long run: If technology advanced and the government created a new surveillance tool that could obtain the same information without a technical trespass, then the government would have the same power as before. Alito and Kagan also both pressed Leckar on whether it would be a search or seizure to attach an inert device to a suspect’s car (that is, a device with no monitoring system). Leckar conceded that this would be a different case, which drew a comment from Justice Kagan that Leckar was really focused on the use of the GPS device, not the installation.

4) Justice Breyer’s reaction was about as far from Scalia’s as you could get. Justice Breyer didn’t buy the technical trespass doctrine, and he wanted to bypass the question of what is a “search” or “seizure” and just ask what is “reasonable.” Breyer seemed to think that the earlier decisions like Karo and Knotts had been about that, as well, which was mistaken: Those cases were primarily about what is a “search,” not when a search is reasonable. (It’s true that the test for what is a search is whether the government conduct violated a “reasonable expectation of privacy,” but that’s a term of art used interchangeably with the phrase “legitimate expectation of privacy” — the word “reasonable” in that term of art is very different from the general balancing test of reasonableness that applies once a search or seizure has been identified.) Anyway, Breyer was therefore looking for some sort of way to say when GPS monitoring was reasonable and desirable, rather than what was a constitutional search or seizure. I don’t think he really found an answer that satisfied him on either side.

5) Justice Sotomayor and Ginsburg were both very worried about the Big Brother implication of using GPS devices: I counted 5 or so references to Orwell’s 1984. At the same time, both were struggling to identify exactly what the constitutional rule was that would regulate GPS monitoring. Merely watching a suspect in a city street was obviously not a search or seizure. Does that change if you switch to video cameras? Lots of cameras? Beepers? GPS devices? Where do you draw the line? Counsel for Jones suggested that the Court could say that this case was a search or seizure but leave open the other cases, but the Justices wanted clearer answers than that. And there was some frustration at the inability to draw constitutional lines from the defendant’s side: At one point Justice Sotomayor responded to one of the defense’s proposed lines by proclaiming, “What an unworkable rule tethered to no principle!”

6) The “mosaic theory” adopted by the D.C. Circuit didn’t seem to go anywhere with the Justices. I think the only Justice who mentioned it during Dreeben’s argument was Chief Justice Roberts. Roberts’ question was straight out of the defense-side briefs, arguing that GPS surveillance over a long period allowed the government to assemble a mosaic, and was much cheaper and easier for the government than the beeper surveillance in Knotts. At the same time, I couldn’t tell if Roberts was asking those questions just to see Dreeben’s response or because he genuinely was sympathetic to the defense side. The mosaic theory came up a bit during Leckar’s argument, but the Justices were mostly very skeptical: As Justice Scalia proclaimed, echoing Judge Sentelle below in his dissent from denial of rehearing en banc, “100 times zero is still zero.” Leckar took the hint and didn’t press the mosaic theory much during his argument.

7) One of the major questionsin the case is how the Justices view the prospect of future statutory regulation. It was clear that a lot of the Justices were deeply worried about the 1984 scenario, and were looking to find a sensible way to regulate GPS surveillance with a constitutional rule if it’s necessary to avoid 1984. Arguing for the government, one of Dreeben’s responses was that these were just the kind of problems that Congress could deal with: If everyone is spooked by the possibility of GPS surveillance, then that is all the more reason for the elected branches to act. It was hard to know exactly what the Justices thought of this: They know they can’t control if Congress acts. If they decide that the Fourth Amendment doesn’t apply because they expect statutory regulation to deal with this, what happens if they are wrong? I tend to think that it’s very likely that Congress would act pretty swiftly to regulate GPS surveillance for the reasons explained in this article, but it’s an question of guessing what the future might look like and I suspect different Justices will look at it differently.

A few weeks ago, I participated on a panel about United States v. Jones, the GPS case, at William & Mary Law School. The panel featured Steve Leckar, who will be arguing the case for Jones; Melanie Wilson, a criminal procedure professor at the University of Kansas (visiting at W&M); and Paul Marcus of W&M. The video has just been posted, and it’s here for those interested. The oral argument in Jones will be on Tuesday.

This is my second post on United States v. Jones, the case on GPS and the Fourth Amendment. In this post, I want to explore whether the act of installing the device should count a Fourth Amendment search or seizure. My bottom-line is that I find this a surprisingly difficult and open question: Justices wishing to apply the Fourth Amendment in a way that is consistent with Fourth Amendment text, history, principles, and precedents could plausibly go either way. One implication of this uncertainty is that if the Justices decide to regulate GPS under the Fourth Amendment, focusing on the installation of the device is a much better option than trying to jump into the thicket of issues discussed in my first post about use of the device once installed. At the same time, it’s worth noting two additional wrinkles. The first is the uncertain standard of reasonableness that would follow from a conclusion that installing the device is a search or seizure. The second is the important role of statutory regulation, which may deal with some of the concerns raised by those who want the Supreme Court to construe the Fourth Amendment to sharply limit GPS monitoring.

I. General Principles on Searches and Seizures

Let’s start with first principles, which I will take in large part from this recent article. The general purpose of the Fourth Amendment is to regulate police collection and use of evidence so that police practices are reasonable. Police officers want to collect evidence to bring cases that prosecutors can charge, and they need two distinct types of power to do this successfully. First, they need the power to uncover and expose evidence so they can see it and recognize its importance to criminal cases. Second, they need the power to “freeze” evidence to maintain custody of it, preserve the status quo pending further investigation, and bring the evidence into court for prosecution. The first power is the power to expose what is hidden, and thereby learn facts that were previously unknown. The second power is the power to secure the scene and add to the potential evidence under the government’s control so eventually it can be used in court.

The Supreme Court has interpreted the government’s search power and seizure power accordingly. Under the Court’s cases, a Fourth Amendment search occurs when the government violates a reasonable expectation of privacy, which in turn occurs when the government observes evidence in a private space. The government’s act of exposing the information from the private space so it is in the government’s view is the search. In contrast, a Fourth Amendment seizure occurs when government conduct meaningfully interferes with an individual’s possessory interest in property. The government’s act of taking control of the property is the seizure.

In the Jones case, federal agents approached the defendant’s car when it was in a public parking lot and affixed a GPS device to the undercarriage of the car. We can break that down into two steps: First, the act of approaching the car and then going underneath it to attach the device to the undercarriage; and Second, the act of actually affixing the device to the car. The question raised by the first step is whether going underneath the car was a search: Put another way, did Jones have a reasonable expectation of privacy in the undercarriage of his car? The question raised by the second step is whether affixing the device was a seizure: That is, did attaching the device meaningfully interfere with the defendant’s possessory interest?

At the outset, it’s important to understand how the Court dealt with a similar issue in United States v. Karo. In Karo, a drug dealer ordered cans of ether from an undercover informant. Federal agents wanted to track the ether so see where the drugs were being prepared for sale, so they purchased a can, put a radio beeper inside, and then painted it to look like a can of ether. With the consent of the informant, the agents placed the can with the beeper amongst the other cans, which the informant then provided to the defendant. Use of the beeper then revealed the location of the cans. In its opinion below, the Court of Appeals had held that the can’s coming into the defendant’s possession violated the Fourth Amendment because “[a]ll individuals have a legitimate expectation of privacy that objects coming into their rightful ownership do not have electronic devices attached to them, devices that would give law enforcement agents the opportunity to monitor the location of the objects at all times and in every place that the objects are taken.” But the Supreme Court disagreed. Transferring the can to Karo’s possession was not a search, the Court held, because it did not reveal any information. It was also not a seizure, because “[a]lthough the can may have contained an unknown and unwanted foreign object, it cannot be said that anyone’s possessory interest was interfered with in a meaningful way.”

The facts of the GPS installation in Jones are somewhat different from the facts of the radio beeper installation in Karo. While Karo knowingly received a package of ether that turned out to include a beeper, the FBI approached Jones’s car, went underneath it, and affixed the GPS device to the undercarriage. In the rest of the post, we’ll see if that should make a difference.

II. Is Going Underneath the Car to Install a GPS Device a Fourth Amendment Search?

Let’s now consider whether Jones had a reasonable expectation of privacy in the undercarriage of his car, such that accessing that part of the car was a Fourth Amendment search. To understand this question, it helps to go back to the inside/outside distinction I explained in my prior post. As I discussed there, most of the Supreme Court’s “search” jurisprudence can be explained by the basic idea that the Fourth Amendment protects inside spaces of persons, houses, papers, and effects, while it does not protect that which is exposed to the general public or is out in the open for all to observe. From this perspective, whether installing the device on the car counts as a search boils down to whether going underneath a car to come close up to its undercarriage is entering an inside space or is merely being in an outside space.

I find this a tricky question. Either view seems plausible. On one hand, you could say that the undercarriage of a car is part of the exterior of the car. The undercarriage isn’t an inside part of the car, like the passenger compartment or the trunk, that often stores private things. Rather, it is an exterior part of the car that is exposed to the public. See New York v. Class (“The exterior of a car, of course, is thrust into the public eye, and thus to examine it does not constitute a ‘search.’”) To be sure, it isn’t all that common for members of the public to go underneath cars parked on a public street. But it happens on occasion, such as when a a person drops something that rolls under the car, a person is looking for something lost earlier, or a kid loses a ball that rolls under the car. And more broadly, when you park on a public street or parking lot, you don’t get some kind of temporary ownership of the physical space underneath the car. The space is still public space. When you agree to put your car in public space, you assume the risk that others will access the space underneath your car. See California v. Greenwood (no reasonable expectation of privacy in trash left at the curb);

That’s one approach. But I think you could equally argue the opposite position. You could say that a person’s car is one of their constitutionally protected “effects,” and clearly entry into the private parts of a car violate a reasonable expectation of privacy, see Delaware v. Prouse. The space underneath a car should be deemed a protected space because social norms recognize an exclusive right to that space. Imagine you parked your car in a parking lot, and you later came back and found someone underneath your car just hanging out. You would probably feel that your space was invaded, and that the person better get out from under your car immediately. From this perspective, the underneath of the car is a private space, not a public one: Although it does not reveal much private information, it does reveal at least some, and that’s been thought to be enough in other contexts. See Arizona v. Hicks (“A search is a search, even if it happens to disclose nothing but the bottom of a turntable.”).

II. Cardwell v. Lewis and New York v. Class

If you really want to get into the weeds on the question of whether accessing the undercarriage of the car is a search — and the Internet isn’t running out of electrons, so why not — you can see the uncertainty of the question by noting that the Court has had a very hard time applying the Fourth Amendment to similar types of government efforts to access parts of cars. (If you’re in a hurry, feel free to skip to Part III. ) There are two particularly relevant opinions, and both offer uncertain guidance. The first is Cardwell v. Lewis and the second is New York v. Class

In Cardwell v. Lewis, the police suspected that Lewis was the driver of a car that had rammed another car off the road. The police arrested Lewis and impounded his car. Officers then went to the police impoundment lot to try to match Lewis’s car to the crime scene. The police visually observed the tire tread on Lewis’s car and noted that it matched the tire tracks at the crime scene. They also scraped some paint off Lewis’s car and noted that it matched the color paint found on the victim’s car at the point of contact. The plurality opinion by Justice Blackmun (joined by Burger, White, and Rehnquist) concluded that this was constitutional, but the opinion itself is maddeningly vague on whether the Court thought a search had occurred. Part II of the opinion starts by seeming to indicate that there was no search, as the conduct only involved the exterior of the vehicle. But then the rest of the analysis seems to say it was a search — albeit one that was constitutionally reasonable because the police had probable cause. It’s just hard to tell which doctrinal box Blackmun had in mind. And given that it is only a plurality opinion for four Justices — no other Justices reached the issue — it’s hard to know what to make of the case.

New York v. Class is equally cryptic. An officer pulled over a car and wanted to see the Vehicle Identification Number (VIN) on the car. In more modern cars, the VIN is located at the front part of the dashboard, normally in plain view through the windshield. But Mr. Class, the driver of the car, had placed some papers over the dashboard. So the officer reached in the car and pulled away the papers to see the VIN. The Court’s opinion by Justice O’Connor concluded that this was constitutional, but the exact reason why is rather uncertain. O’Connor’s analysis begins by arguing that there is no reasonable expectation of privacy in a VIN, given how regulated cars are and given that the VIN is usually visible. But this makes little sense: Fourth Amendment doctrine is generally concerned with how the police got to the information, not whether the information has some transcendental value as protected or unprotected. The opinion then concludes that entering the car to remove the papers and see the VIN was a search but a reasonable one, given a balancing of all the factors: The fact that there was no expectation of privacy in the VIN, the fact that the officer only looked where the VIN could be, and the fact that the officer had seen two traffic violations. The Court also adds that although entering the car to remove the papers was a search, neither ” the doorjamb or atop the dashboard [of a car] . . . is subject to a reasonable expectation of privacy.” The end-result is a head-scratcher, I think. It’s hard to know exactly what counts as a search and what the framework is for reasonableness.

In my view, the chief lesson of Cardwell and Class is that the Court struggles to apply the inside/outside distinction in the automobile setting. Cops watching a car from afar is clearly outside; the act of physically entering the passenger compartment is clearly inside. But going underneath the undercarriage when the car is on a public parking lot is somewhere between the two, and there are relatively sparse source of authority on where the line should be drawn.

III. The Implications of a Possible Ruling that Installing the Device on the Undercarriage is a Search

So let’s imagine the Supreme Court agrees with defendant that going underneath the car to install the GPS is a “search,” but then agrees with the government that use of the GPS is not a search. What would the law of GPS surveillance look like? It seems to me that the law would regulate installing devices that are hidden — that is, on the bottom of the car — but would not regulate the Karo situation of a suspect who receives a package containing the GPS. Similarly, the rule would not regulate turning on a GPS device that was built-in to the car (as that seems clearly covered by Karo). Further, the Court would then need to reach the interesting and potentially difficult issue of what would make such a search “reasonable.” As we saw in Cardwell and Class, the “search” inquiry is only half the battle: The Court would then have to say when the search of an undercarriage is reasonable, which may not require a warrant. But at the very least the Fourth Amendment would regulate the act of attaching a secret GPS device to a suspect’s car.

Different readers will have different views on whether this avenue is a desirable one for the Court to take. In my view, though, it’s the easiest and most coherent way for the Court to regulate GPS surveillance under the Fourth Amendment beyond the Knotts/Karo line discussed in my previous post. Recall my concerns from my previous post about rejecting the inside/outside distinction. Inside/outside is in many ways the bedrock of the Supreme Court’s “search” jurisprudence. If you reject that, then you need to find an alternative (which proves extremely difficult). But regulating GPS surveillance by focusing on the installation of the device is much easier. It sticks with the inside/outside distinction and simply treats the entry to install the device as an entry “inside” and therefore a search. That approach doesn’t trigger any of the conceptual puzzles that would arise if the Court were to try to regulate GPS usage (as opposed to installation) beyond the Knotts/Karo line.

Continue reading ‘My View of the Second Question Presented in United States v. Jones, the Fourth Amendment GPS Case’ »

On November 8th, the Supreme Court will hear oral argument in United States v. Jones, the case on whether installation and/or use of a GPS device on a suspect’s car to record the public places the car travels is a Fourth Amendment search or seizure. I wanted to offer my thoughts on the case.

At the outset, here’s my bottom line: I’m not sure which side should win. On one hand, I don’t think use of the device should be deemed a search or seizure. On the other hand, I am genuinely divided on whether I think the installation should be deemed a search or seizure. Given these two positions, I don’t have an answer to whether the combined installation and use should be permitted without Fourth Amendment oversight (although I have a lot of views on better or worse ways to get to either result). Regardless of how the Court rules, however, I think a new privacy statute is needed to address both government and private sector use of GPS surveillance.

I’m going to make that case over three posts. In this post, I’m going to address the first Question Presented (QP) in Jones: Whether the use of the device to obtain location information should be deemed a search or seizure. (My answer: No.) In the next post, I’m going to address the second QP, whether installation of the device is a search or seizure. (My answer: I’m divided.) And in the third post, I’m going to address the need for and likelihood of statutory regulation of GPS, especially if the Court rules for the government in the Jones litigation.

So that’s the game plan. On to the first post, on whether use of the device is a search.

I. The Inside/Outside Distinction

Let’s start with first principles. The text of the Fourth Amendment states that the Amendment protects security in “persons, houses, papers, and effects,” and the Fourth Amendment’s prohibition on unreasonable “searches” does so by protecting invasions into those private spaces. Over the years, the Supreme Court has developed a relatively simple line for distinguishing the invasions into persons, houses, papers, and effects that the Fourth Amendment regulates as “searches” from the investigative steps that the Fourth Amendment does not regulate. That distinction is the line between what I will call inside surveillance and outside surveillance: Surveillance of outside spaces is always permitted, while surveillance of inside spaces is a regulated “search.”

Consider a few examples. Government entry into a home is a search, as is entry into a car, or a sealed package, or a letter, or a person’s pockets. These are all intrusions into persons, houses, papers, and effects. They are all searches. On the other hand, surveillance in public places that does not enter into private spaces, such as watching someone on the street, looking at their faces, examining the outside of their packages, overhearing their voice, or following someone in a store open to the public, is not a search. These are not intrusions into persons, houses papers, or effects, and they are not searches under the Fourth Amendment.

Interestingly, you get these same results regardless of version of the Supreme Court’s doctrine you apply. You get the same results whether you get these results under the “protected areas” test that preceded the 1967 Katz case, or the Katz “reasonable expectation of privacy” test that the Court has adopted since then. The results are the same: A search occurs when the government intrudes upon a private person, house, paper, or effect, but does not occur when the government merely observes something in a public space or in a space where the government is otherwise entitled to be. I will refer to this using the short-hand of inside versus outside surveillance, as I did in this article.

The fundamental distinction between inside and outside surveillance leads to some close calls, to be sure. For example, imagine the police approach a home, walk directly up to an open window, press their faces up to the window, and peer in to see what is in the room inside. Technically, that is surveillance from an open space, but functionally it is surveillance of the inside of the home. Is that protected inside surveillance, or unprotected outside surveillance? The Supreme Court has created the distinction between “curtilage” and “open fields” to answer that: The outside area immediately around the home that can be used to peer inside the home is treated as inside surveillance (curtilage) rather than outside surveillance (open fields). See United States v. Dunn. Similarly, imagine the police use a thermal imaging device to determine the exterior temperature of a wall on the home. Is that outside surveillance, as it is only of the outside of the wall exposed to the public, or is that inside surveillance, as it reveals information about the inside of home? It’s a tricky call, as the 5-4 decision in Kyllo v. United States reveals. But the basic point remains: The distinction between inside and outside surveillance is the basic building block of the Supreme Court’s “search” cases.

II. The Knotts and Karo Precedents from the Radio Beeper Era

How does this distinction apply to the use of government surveillance devices installed to determine the location of property used or controlled by a criminal suspect? The Supreme Court first grappled with this in two cases in the 1980s, United States v. Knotts and United States v. Karo. Both cases involved radio beepers provided by the government that the suspects did not realize were present and broadcasting their location. The technology was crude compared to today’s GPS technology, but it did the job: It enabled the government to know the location of the beepers, and thus, implicitly, the location of the suspects that the police wanted to follow.

Knotts and Karo reasoned that the way to translate the traditional Fourth Amendment protection to the era of high-tech radio beepers was to focus on the information that the surveillance devices revealed. Recall that the traditional Fourth Amendment rule was that the police could always watch a suspect in public (no search), but that they could not enter protected spaces without a warrant or some Fourth Amendment oversight (a search). Knotts and Karo together drew the same line for government-installed location devices: If the device is used to monitor a location in public, then no search occurred (Knotts), but if the device was used to monitor a location inside a protected space, like a home, then a search occurred (Karo).

To my mind, there is a lot of wisdom in the Knotts/Karo line. As I argue in a forthcoming article, it is a constant challenge for courts to adjust Fourth Amendment rules to maintain the level of constitutional protection as technology changes. I think Karo and Knotts did that quite well: They maintained the basic distinction between inside and outside surveillance by focusing on whether the information obtained was information about what was happening outside (the location of property out in public) or what was happening inside (the location of property inside a home). The facts changed, but the Knotts/Karo line maintained the same equilibrium of police power and privacy rights across that shift from one technology (visual surveillance) to another (radio beepers).

III. Does GPS Surveillance Justify A Departure from the Knotts/Karo Line?

That brings us to Jones. In Jones, a GPS device was placed on the suspect’s car. The trial court concluded that the evidence of the GPS device in the suspect’s garage had to be suppressed under Karo, but that the evidence of the GPS device in public was permitted under Knotts. Only the latter evidence, the evidence of the location of the car on the public street, is at issue in the Jones case. The basic argument of the defendant-respondent in Jones is that GPS surveillance is different from radio beeper surveillance, and that those differences justify a departure from the Knotts/Karo information-based approach. The gist of the argument is that GPS monitoring is just too invasive to be allowed without judicial oversight — the monitoring is too constant, too easily done, too continuous, and too detailed.

As I understand this argument, the basic move is to replace the inside/outside distinction with a different approach, one based on more amorphous standard of what is very invasive. According to the respondent in Jones, the Fourth Amendment should not track inside versus outside: Rather, it should measure an overall amount of invasiveness. Under that approach, a person can have a reasonable expectation of privacy in open public spaces just as they can in private spaces. What matters is whether the manner in which the public or private surveillance is conducted is too invasive and creepy to go without Fourth Amendment protection, not whether the monitoring happens to be of public and open or private and enclosed spaces.

I think this is a unpersuasive argument, and that the Justices should reject it for three reasons.
Continue reading ‘My View of the First Question Presented in United States v. Jones, the Fourth Amendment GPS Case’ »

Thanks to Lyle Denniston, I learned today that the Justice Department has just filed its brief in United States v. Jones, the pending Supreme Court case on whether installing and using a GPS device to detect the location of a suspect’s car without a warrant violates the Fourth Amendment. The DOJ brief is an interesting example of how Fourth Amendment arguments are constructed, so I wanted to blog a bit about it. I’ll start with a bit of context from a recent law review article, and then break down the government’s arguments accordingly. I’ll then make some quick predictions about arguments the Respondent’s brief might make.

I. The Four Models of Fourth Amendment Protection

A few years ago, I wrote a law review article on the “reasonable expectation of privacy” test in Fourth Amendment law: Four Models of Fourth Amendment Protection, 60 Stan. L. Rev. 503 (2007). My argument was that the “reasonable expectation of privacy” test was really four different tests — that there were four different kinds of arguments that the Supreme Court made about when the government violates a reasonable expectation of privacy and therefore is a Fourth Amendment “search.” Here are the four models I identified:

(1) the probabilistic model, by which an expectation of privacy is reasonable or not based on how common or expected the government’s conduct appears to be.
(2) the private facts model, by which an expectation of privacy is reasonable or not based on the nature of the information disclosed regardless of how it is obtained,
(3) the positive law model, by which an expectation of privacy is reasonable or not based on whether the government’s conduct violated some source of law outside the Fourth Amendment, and
(4) the policy model, by which an expectation of privacy is reasonable or not based whether it is desirable to have that outcome as a matter of policy.

Just to be clear, the models generally are not named. Rather, these are arguments that the courts use.

My article argues that the Supreme Court uses all four models instead of just one model because no one model accurately distinguishes less intrusive from more intrusive law enforcement steps, which is what the reasonable expectation of privacy test needs to do. Briefs and opinions therefore tend to mix and match the models, making arguments using the model or models that support the argued-for result in that particular context.

The result is rather messy, and gives all sorts of room to the Justices to justify different results. But it also enables a workable regulatory system that gives substantial guidance to the lower courts. The law ends up relying on some models in some contexts and other models in other contexts, ideally in ways that pick models based on what models best track the invasiveness of the government’s conduct in that factual setting.

II. The Government’s Merits Brief in United States v. Jones

In United States v. Jones, the police attached a GPS tracking device to the suspect’s vehicle and tracked the vehicle’s location on public streets over time. The first question raised by the case is whether the use of the GPS device violated the suspect’s “reasonable expectation of privacy.” DOJ’s brief is a nice case study of how arguments based on the four models tend to work.

Here’s how the arguments break down. The government’s main argument is based on the private facts model. In prior precedents, the brief explains, the Court has said that location information about a car on public streets is not protected. In other words, the fact that a car is in a particular place on a public street at a particular time is simply not a private fact. The same approach should govern here, the brief contends. What matters is the information obtained, and here the information obtained was not private for Fourth Amendment purposes. See pages 17-22.

The government’s brief next argues that the Supreme Court should reject the probabilistic model. The most relevant cases have rejected the probabilistic model, the brief explains (citing Knotts and Smith), while the cases that embraced the probabilistic model (such as Greenwood and Bond) are very different on their facts. The Court should therefore ignore what the DOJ brief calls “the likelihood approach” to the Fourth Amendment in this case. See pages 22-27.

After a foray into why the mosaic theory won’t work, see pages 27-33, the DOJ brief then argues using the policy model. There has been no evidence of abuses of GPS surveillance, the brief argues. The legislature is ready to regulate this area in the absence of Fourth Amendment protection. As a result, the brief argues, there’s no need to subject GPS surveillance to a warrant requirement as a matter of policy. See pages 33-37.

In a long footnote, the DOJ brief then argues against using the positive law model here. Although some state laws make it unlawful to install a tracking device without a warrant, such laws should not influence whether an expectation of privacy is reasonable. See pages 36-37 n.4.

The brief then concludes this part of the argument by returning to the private facts model. The “type of information” that the GPS device revealed was not private, and therefore there was no violation of a reasonable expectation of privacy. See pages 37-39.

III. Guessing the Arguments of the Respondent’s Brief

If you want to predict what the Respondent’s merits brief will look like, the Four Models make it possible to offer some educated guesses.

First, the Respondent’s brief probably will push the models that the DOJ brief rejected. The Respondent presumably will press the probabilistic model and argue that reasonable people don’t expect this sort of surveillance. Second, the brief likely will press the positive law model: It will detail the laws requiring warrants for tracking devices and explain how such an interference with property is a traditional trespass. For both reasons, the brief will argue, the use of a GPS device violates a reasonable expectation of privacy.

The Respondent’s brief will then explain how the private facts and policy models cut in its favor, not the government’s. The brief will take a macro view of the information obtained in order to use the private facts model. That is, the brief will look at the information obtainable in the aggregate and argue that the aggregate facts are private under a private facts approach. Finally, the Respondent’s brief will almost certainly use the policy model to offer a very different picture of the policy implications of allowing GPS to go unregulated.

In short, the two sides will end up offering dueling sets of models. Each side will press some of the models and de-emphasize or reject others, leaving it for the Justices to figure out which models should govern and how they should apply in this particular case.