Carpenter v. US: SCOTUS Theories of the 4th Amendment

The Supreme Court ruling in Carpenter has huge implications for law enforcement in the digital age

In its biggest Fourth Amendment case of at least this year, the Supreme Court’s 5-4 ruling came down June 22 in Carpenter v. United States, ordering that collection of historical cell site location information, or CSLI, should “generally” require police to get a warrantAlong with many other organizations, Restore The Fourth had recognized how significant this case was likely to be, and we filed an amicus brief in the case. We argued that:

  • Despite the so-called “third-party doctrine”, even when people disclose their information to third parties, that should not mean that they do not have a reasonable expectation of privacy;
  • Over time, cell site location information will become more revealing, thanks to increased density of tower locations and the increased power of computers to algorithmically parse information;
  • Police warrantless use of CSLI comes with an unusually high risk of abuse.

The majority opinion, written by Chief Justice Roberts and joined by Breyer, Ginsburg, Kagan and Sotomayor, agreed at least with the first two of our points.

Amy Howe, writing for SCOTUSBlog, ably summarizes the facts of the case:

Timothy Carpenter, who was convicted and sentenced to almost 116 years in prison for his role in a series of armed robberies in Ohio and Michigan. Law-enforcement officials used cell-site records from his cellphone provider to place him in the vicinity of the crimes, but Carpenter argued that the jury should not hear about those records because the government had not obtained a warrant for them. A federal appeals court upheld his conviction, explaining that the government was not required to seek a warrant because Carpenter could not have expected cellphone records maintained by his service provider to remain private. This morning the Supreme Court reversed that ruling.

Here is Restore The Fourth’s Litigation Working Group chair, Mahesha Subbaraman, being interviewed on the case:

When A Warrant Is Required

Perhaps the most confusing part of the ruling is that Chief Justice Roberts insistently declares that the circumstance where a criminal suspect has a reasonable expectation of privacy in records held by a third party will be “rare”, and that therefore requiring a warrant for searches of historical CSLI will not disrupt a broad swath of police practice. Though Roberts may have an expectation of rareness, in reality searches of historical CSLI are common, and are bound by the Carpenter opinion even if Roberts feels the need for a rhetorical flourish as to their rareness. For that reason, the main dissent, authored by Kennedy, is right to say that the majority’s “reinterpretation of Miller and Smith will have dramatic consequences for law enforcement, courts, and society as a whole.” The fact that it is common practice for government to requisition financial or telephonic information without bothering with the formality of a warrant is a bug, not a feature, and correcting that is part of the process of restoring the Fourth.

The majority opinion regards historical CSLI as categorically different from the kind of financial records at issue in Miller, because historical CSLI is a long-term record of people’s movements over time; but this effectively carves out a subset of particularly intrusive metadata and affords it warrant protection, rather than maintaining the content/metadata distinction that has underpinned Fourth Amendment law since the 1970s – as Kennedy’s dissent puts it, it “draws an unprincipled and unworkable line between cell-site records on the one hand and financial and telephonic records on the other.” The line will likely be much litigated.

Responding to the time limit in the case before it, the Court declared that the government asking for seven days of historical CSLI, but actually receiving only two, would trigger a warrant requirement, implicitly indicating that asking for six days’ worth would not – perhaps, even if what the government actually received was six days’ worth. This is clearer than simply saying, as courts tend to do in the area of the Fourth Amendment, that whether warrant protection is triggered “depends on the totality of the circumstances”, but not by much. Why seven days of requested data in particular? Because Carpenter says so. This rule, and the ruling more broadly, offers little to those who thirst for clarity and administrability in Supreme Court rulings.

Two Theories of Why a Warrant is Required

A matter of deep interest to court-watchers was not only whether warrant protection would be given to historical CSLI, but why. A key division on the Court continues to be between those who are comfortable with continuing to develop the sixty-year-old Katz “reasonable expectations of privacy” test, which determines whether something is a search on the basis of whether the person searched has had an “expectation of privacy” violated that “society is prepared to recognize as reasonable”; and those who prefer to examine the question of whether something is a search exclusively through a property-focused lens, to understand whether a “trespass” can be deemed to have occurred.  This particular opinion showcases that split, with the Court’s liberal Justices, plus Roberts, in the Katz camp, and Alito, Gorsuch, Kennedy and Thomas, in their different ways, in the property-rights camp. At Restore The Fourth, we don’t believe that either the Katz approach or the property-rights approach is wrong. Either can lead to a restoration of people’s privacy as against government searches and seizure; the debate on the Court between these camps has so far been immensely productive of increased protections.

Thomas dissents separately, he says, because in law, historical CSLI relating to Carpenter’s movements does not belong to him; if it does not belong to him, then it cannot be deemed a “paper or effect” of Carpenter’s; and therefore he cannot claim a violation of the Fourth Amendment with respect to him. The FCC does say that “to the extent that” CSLI should be considered property, it should be treated as the property of the customer, not the carrier. Thomas declares that this is “weak”, and Alito, in a dissent joined by Thomas, argues that the Founders did not envision a situation where the ordinary processes of requiring documents to be produced in a criminal proceeding (subpoena duces tecum) would be subject to the requirements of a warrant.

The difficulty with drawing originalist analogies is that you get to pick and choose the analogy. Thomas sketches out a situation where of course the Founders accepted that the Fourth Amendment would not be relevant to subpoenas of documents from third parties. He chooses not to sketch out a situation where the Founders are confronted by a warehouse, owned by a trading company, containing physical documents attesting to the minute-by-minute whereabouts of every resident of the American colonies, and accessible on a trivial showing by agents of the Crown. Had he chosen that analogy, then of course the Founders would have thought that the powers of the Crown over the colonials were thereby rendered excessive. Through choice of analogy, originalism sometimes risks becoming the same exercise in projection of contemporary assumptions over the Constitution that originalists decry.

We can see the difference in choice of analogy in the profound and interesting Gorsuch dissent. Gorsuch plainly and intelligently skewers the limitations of both a “king always wins” rule as envisioned by broad application of Smith and Miller, and the vagueness and plasticity of the majority opinion’s limiting language based on the Katz “reasonable expectation of privacy” test:

“At what point does access to electronic data amount to “arbitrary” authority? When does police surveillance become “too permeating”? And what sort of “obstacles” should judges “place” in law enforcement’s path when it does? We simply do not know.”

Gorsuch finds that Carpenter has, if not a full right to treat CSLI as his own property, then at least enough of a property interest for Fourth Amendment purposes that he can claim that his “papers or effects” were searched. Without entirely dismissing Katz, he charts out a method for applying a property-based theory of the Fourth Amendment whereby state legislatures’ efforts to protect people’s privacy in the data held about them by third parties could be construed by courts to create property rights in that data. He uses Ex parte Jackson (1878), a case relating to the privacy of letters sent via USPS, to indicate that there is some “constitutional floor” of protection in such records below which state laws cannot go, for example by declaring that they can be seized and searched at will. And, as he has done in prior opinions, he uses the eighteenth-century analogy of the duties of a bailee as a way of dealing with the problems caused by the third-party doctrine that would allow an originalist-minded Court to accept a property interest in both CSLI and in business records held by third parties more generally.

Evidently, Gorsuch’s Fourth Amendment analysis has not yet persuaded a substantial portion of the Court to join him; but just as Sotomayor’s innovative concurrence in Jones (2011) now underpins the majority opinion in Carpenter, it would not be surprising if Gorsuch’s theory of how the Fourth Amendment should develop in the light of technological change were to become significantly more influential in the years ahead.

Implications for National Security Surveillance

Justice Roberts emphasized that the holding that a warrant was required “does not consider other collection techniques involving foreign affairs or national security.” Though these words sound cautious, they are potentially a landmine laid under the ramifying superstructure of the surveillance state. First, of course, he is not saying that Carpenter’s reasoning could not validly apply to the oceans of metadata collected by the surveillance agencies, only that such collection was not before the Court in this ruling. Second, the emphasis is that Carpenter does not consider other collection techniques involving foreign affairs or national security, which (it will surely shortly be argued) most naturally suggests that the Court does think a warrant should apply to historical CSLI collection in particular even when it involves foreign affairs or national security, when (assumedly, given other precedents) that collection occurs in the United States.

This matters immensely, because the communications metadata of an unknown number of Americans, but probably numbering in the millions, is being collected under the authority of Section 702 of the FISA Amendments Act. The Americans being collected upon are either contacts of, or are talking about, one of over 100,000 “targets”, who can be any foreign national whose communications might be of intelligence interest to the United States – they don’t have to be, and mostly are not, terrorists. Whether, in a future ruling, the Supreme Court will be willing to explicitly rule that such collection requires a warrant depends in large part on the ability of plaintiffs in surveillance cases to resolve the aching problem of standing – i.e., to be able to prove to the Court’s satisfaction that, as US citizens, they have in fact been surveilled by a surveillance agency; and that surveillance of their historical CSLI in particular has caused them a harm that the Court is prepared to recognize.

The FBI in particular has a lot of reason to worry. The ruling may not explicitly overrule Smith v. Maryland, the phone metadata case that underpins the legal justification for mass surveillance of telephonic metadata; but it signals that a majority of the Supreme Court thinks that there are major problems in applying the reasoning of Smith to police surveillance cases.


Carpenter is a hugely significant ruling in the Supreme Court’s Fourth Amendment jurisprudence. For the first time, the Court has clearly recognized that citizens have a cognizable interest in a particular type of records about them held by third parties. But, as with Jones, it is important not so much for adding clarity, as for marking a step in the Court’s circuitous journey towards a clearer understanding of how law enforcement use of data affects our individual freedoms. Thanks to Chief Justice Roberts’ leadership in extending privacy protections to data generated by new technologies, and to the recent additions of Sotomayor and Gorsuch as important and very different voices willing to rein in police surveillance, we have reason for hope. We should expect a continued flood of Fourth Amendment litigation, and continued conflicts as the Court wrestles with why and how to maintain individual privacy in the digital era. It’s enough for now to note that the discussion within the judiciary on this topic, in both its content and its results, currently far outshines the work product of the other two branches of government.

Op-Ed: Supreme Court Rulings in Hernandez v. Mesa and Ziglar v. Abbasi

Rulings in Ziglar and Hernandez: The Supreme Court, the Fourth Amendment and the `Special Factor’ of `National Security’

In Hernandez v. Mesa and Ziglar v. Abbasi, two just-decided cases, the Supreme Court has now made it such that individuals wishing to obtain damages from agents of the federal government for violation of their Fourth Amendment rights have very limited avenues left to do so.

These claims are called “Bivens claims”, after the 1971 Supreme Court case Bivens v. Six Unknown Federal Agents, which was a suit for damages against agents who conducted an unreasonable, warrantless search of a private home, using excessive force. Under Ziglar, any new case not closely (or even, for Justice Thomas, “precisely”) resembling the situation in Bivens must be subjected to a broad-ranging `special factors’ test as to whether the courts should `hesitate’ to create a new ground for Bivens claims. New types of claims, Ziglar suggests, should be denied if Congress has not signaled support for such claims. Bivens claims are not “a proper vehicle for altering an entity’s policy” and are “not designed to hold officers responsible for acts of their subordinates.” If brought directly against executive officials for their own actions, a successful claim would “interfere with sensitive Executive Branch functions” of policy deliberation. If the claim would involve inquiry into “national-security policy, hesitation is warranted, because that “is the prerogative of Congress and the President.” The “proper balance in situations like this, between deterring constitutional violations and freeing high officials to make the lawful decisions necessary to protect the Nation in times of great peril, is one for the Congress to undertake, not the Judiciary.” This is a substantial extension from the “special factors” cited to in Bivens, which suggested hesitation only in cases involving “federal fiscal policy”, cases where the agent’s conduct was “contrary to no constitutional prohibition”, and cases where Congress had barred money damages in particular.

One issue here, among many, is that “national-security policy” now, relative to 1971, is used to cover a vast array of activities by the federal government. Infrastructure? Sure. Global warming? Absolutely. Border policy? Why not?

Beyond that, “national security” is the constant refrain of those in government who seek to conceal merely embarrassing or unpopular conduct. National security, as the Ninth Circuit has put it in this year’s `travel ban’ cases, is often used as a “talismanic incantation that, once invoked, can support any and all exercise of executive power[.]” Such talismanic uses deserve increased alertness from the courts, not increased deference. In truth, no Supreme Court decision, in our current hegemonic situation, is capable of rendering the executive unable to defend the country. Our military is well-founded and technologically advanced; there is no prospect of foreign invasion.

Since “national security” is such an interpretive inkblot, asking courts to accept or deny damages claims on the basis of it leads only to arbitrary decisions based on judges’ prior biases. One could as easily argue that detention of Muslims without charge (Ziglar) or a CBP agent shooting a Mexican teenager harms national security as hurts it. When dealing with such a protean concept, any argument is possible; Ziglar’s novel inclusion of “national security” as a “special factor counseling hesitation” is highly dangerous and overbroad.

In Hernandez¸ a 15-year-old Mexican national was shot in a culvert from across the invisible line separating the U. S. from Mexico, by a border agent, and his surviving family wished to bring a Bivens claim for damages under the Fourth Amendment. However, the Fourth Amendment is often conceived of as being primarily a collective right that pertains only to those who have acted to make themselves in some sense part of “the people” of the United States (see, for example, the plurality ruling in U. S. v. Verdugo-Urquidez [1990]). As such, it is hard to apply it on behalf of an individual who had never apparently been to the United States, nor taken any steps to render himself part of “the people.” A Guantanamo case, Boumediene v. Bush [2008], did permit non-citizens outside the US to bring a habeas corpus claim. So, when Hernandez was accepted for argument before the Supreme Court, at least four Justices wished to see the following three questions answered:

May qualified immunity be granted or denied based on facts—such as the victim’s legal status— unknown to the officer at the time of the incident?

Whether the claim in this case may be asserted under Bivens v. Six Unknown Fed. Narcotics Agents, 403 U. S. 388 (1971)?

Does a formalist or functionalist analysis govern the extraterritorial application of the Fourth Amendment’s prohibition on unjustified deadly force, as applied to a cross-border shooting of an unarmed Mexican citizen in an enclosed area controlled by the United States?

The Court was able to agree only on the first of these, that the government was mistaken in arguing that Agent Mesa should enjoy “qualified immunity” for his actions, because that immunity could only be based on facts known at the time. They remanded to the lower court the question of whether the claim could be asserted under Bivens in light of Ziglar, heavily hinting that “special factors” would apply.

It is hard to see how even under the new “special factors” envisioned in Ziglar, the situation in Hernandez would require denial of the Bivens claim. The aim of the suit in Hernandez is not to alter policy at the border – indeed, the Customs and Border Police, in light of this case and an analogous Ninth Circuit case, have already revised their policy. The aim of the suit is not to hold Agent Mesa’s superior officers responsible for his own actions. Congress has not barred such suits for damages. Perhaps, the Supreme Court could be viewing border control as an aspect of “national-security policy” to which the Courts should be deferential. However, in this case Agent Mesa is conceded by both sides to have acted contrary to CBP policy in shooting Sergio Hernandez, even if there are arguments about how intentionally he did so. If the Fifth Circuit finds accordingly, it would be possible, even under Ziglar, for them to conclude that a Bivens claim could proceed.

The last and largest of these three questions, on whether a formalist or functionalist analysis governs the extraterritorial application of the Fourth Amendment, was the main topic of our brief, which argued that the history of claims by non-US persons against US government agents shows that the Constitution does not give power to its agents to arbitrarily deprive non-US persons of life. This question was only really addressed in a dissent authored by Justice Breyer and joined by Justice Ginsburg, who tried to construct a basis for allowing a claim by Hernandez’ surviving family because of the “special border-related features” and “limitroph[ic]” nature of the border in the El Paso-Ciudad Juarez area, but their arguments did not secure a majority.

To our disappointment, these rulings, rather than confronting and correcting the adverse consequences of current agency practices, defer their resolution to another day. Eventually, however, even if not explicitly in this case, the Court will have to rule on the third question above, and when they do, it will be fascinating.