The Yale Law Journal


Secrecy, Intimacy, and Workable Rules: Justice Sotomayor Stakes Out the Middle Ground in United States v. Jones

24 Mar 2014
Miriam H. Baer

In this Essay, Professor Miriam Baer focuses on Justice Sotomayor’s concurrence in United States v. Jones, which has attracted widespread notice due to Justice Sotomayor’s suggestion that the Court reconsider its reasonable expectation of privacy test and the related third-party doctrine. Professor Baer argues that Justice Sotomayor’s opinion exemplifies an attempt to stake out a “middle ground” approach to Fourth Amendment debates over surveillance and technology, one which foregrounds intimacy and common-sense rules as guiding principles.

One can hardly consider criminal procedure without contemplating the Fourth Amendment’s reasonable expectation of privacy test and its partner in crime, the third-party doctrine. These doctrines work in tandem to strip an individual of Fourth Amendment protection she might otherwise claim over the information she “knowingly exposes to the public.”1 Over the past half century, the two doctrines have enabled the government to develop and undertake a broad variety of investigative techniques with virtually no judicial oversight. Not surprisingly, both doctrines increasingly have come under attack as rapidly changing technology renders surveillance cheaper and more invasive.2

The Supreme Court recently reflected these surveillance-related concerns in its resolution of United States v. Jones.3 Prosecutors may ruefully recall Jones as the case that should never have been. A joint task force investigating narcotics activity placed a global positioning system device (GPS) on the undercarriage of a car and used it to track the car and its driver’s movements for twenty-eight days.4 Ironically, the officers investigating the case already had probable cause to believe the car was being used for illegal activity; they had secured a warrant to place the GPS on the car and monitor its movements.5 But they violated the terms of the warrant by acting outside its geographic and temporal limits.6 Conceding that they had violated the warrant, the police invoked their fallback argument that no warrant was required in the first place. Nine Justices disagreed.

The majority opinion that disposed of Jones’ case is narrow; writing for five members of the Court, Justice Scalia concludes that the attachment of the GPS constitutes a “search” because it physically intrudes upon the defendant’s “effects,” namely his car.7 The opinion thus revives the property-based definition of Fourth Amendment searches and effectively discards previous holdings that had severed the connection between a Fourth Amendment “search” and local property law.8 Despite this jurisprudential development, the majority’s opinion bears far less potential significance for law enforcement agencies than the two concurrences in the case—one penned solely by Justice Sotomayor, and the other authored by Justice Alito and joined by Justices Ginsburg, Breyer, and Kagan.9

Justice Alito’s opinion, which concurs only in the judgment, sounds far more like a dissent.10 Criticizing the majority for its originalist approach,11 Justice Alito’s opinion embraces the mosaic theory that emerged in Judge Ginsburg’s appellate decision below: however proper warrantless monitoring of a single trip through public streets may be, that propriety disappears when the monitoring becomes a four week dragnet.12 In other words, the sum of the government’s monitoring activity can become a Fourth Amendment search, even if its component parts do not.13

Justice Sotomayor’s opinion, in which she concurs with the majority but simultaneously endorses some of Justice Alito’s reasoning, reveals much about the Fourth Amendment’s possible evolution. Despite its brevity and its sole authorship, Justice Sotomayor’s concurrence has already been cited numerous times by scholars and lower courts.14 A Harvard Law Review comment analyzing the case strongly praises Justice Sotomayor’s opinion as “offering ideas for reform and preserving a full doctrinal toolkit for posterity.”15

While agreeing with Justice Scalia’s majority opinion that the government had “usurped Jones’ property for the purpose of conducting surveillance on him,” Justice Sotomayor opines that future government actions could very well intrude upon privacy, “even in the absence of a trespass.”16 She then goes on to consider how the Fourth Amendment’s reasonable expectation of privacy test (articulated nearly fifty years ago in Katz v. United States17) can best take into account changes wrought by technology—and, in doing so, bluntly questions the continuing viability of a doctrine that leaves evidence held by third parties unprotected by the Fourth Amendment.18 Thus, in fewer than ten paragraphs, Justice Sotomayor questions and reframes two of the oldest and most criticized doctrines in modern Fourth Amendment jurisprudence.19

Commendably, Justice Sotomayor’s opinion stops short of creating the drastic change in Fourth Amendment jurisprudence that some scholars seek.20 Her concurrence poses a series of difficult questions, but stops short of definitively resolving them. Nevertheless, if one looks closely enough, one can find within Justice Sotomayor’s opinion a more plausible conception of Fourth Amendment privacy and a useful framework to implement it.

Crafted with an eye towards devising workable pragmatic rules, Justice Sotomayor’s discussion of GPS monitoring’s attributes offers a template for deciding future cases. On a superficial level, her opinion states simply why certain law enforcement activities invoke the average citizen’s concern. On a much deeper level, her observations form the core of a framework that can be employed to distinguish future “searches” from non-searches. More useful to courts and law enforcement agents than Justice Alito’s declaration that four weeks of real-time surveillance transgresses some imaginary boundary, Justice Sotomayor’s opinion begins the hard work of accommodating society’s need for effective law enforcement and its conflicting concern with preserving privacy in an increasingly sophisticated technological world.

The need for pragmatic, workable rules becomes particularly salient when one considers the category of misconduct known as white-collar crime. Harmful misconduct such as fraud relies on and is often proven by reference to information contained in documents, which in turn are often collected and maintained by third parties. Until now, prosecutors have been able to prove these types of cases by using a wealth of information obtained via grand jury and administrative subpoenas, not to mention statutes that impose a variety of recordkeeping obligations on corporate and commercial institutions.21 Accordingly, the adoption of mosaic theory22 might well unleash a set of unintended consequences—not only relating to the continued prosecution of garden-variety mail frauds, but also for the continuing viability of the modern administrative state, which relies almost entirely on the collection, maintenance, and production of documents, often with little to no individualized suspicion of wrongdoing.23

The Supreme Court has long sought to provide ex ante guidance to law enforcement agents and ex postguidance to trial courts. Whereas the more expansive notions of mosaic theory threaten interpretive anarchy,24 Justice Sotomayor’s sober and pragmatic analysis avoids such conceptual uncertainty and sets in place the beginnings of a framework that may prove valuable for both those who apply Fourth Amendment principles on the ground and those who do so from the bench. As a result, one should not be surprised if Justice Sotomayor’s Jones concurrence eventually attains the same recognition as Justice Harlan’s concurrence in Katz commanded almost five decades ago.

The remainder of this Essay unfolds as follows. Part I explores historical precedent by considering Justice Harlan’s concurring opinion in Katz,25 which lays the foundation for the reasonable expectation of privacy test,and Harlan’s later dissent in United States v. White,26 wherein he expressed disappointment with the way his test appeared to unfold. Part II then goes on to consider Justice Sotomayor’s concurrence in Jones. I argue that it is significant because it conceptualizes privacy not as a form of secrecy, but rather as an expression of intimacy. Rhetorically asking a series of questions, the opinion then offers a set of guidelines that courts might utilize in distinguishing between intimate and non-intimate conduct.

Finally, Part III assesses this framework’s usefulness by considering its application to white-collar crime. Any rollback of either the Katz test or its related third-party doctrine would seriously constrain the government’s ability to investigate and prosecute document-intensive crimes such as fraud.27 Some might conclude that this concern is misplaced or simply irrelevant.28 Others, however, are likely to respond just as strongly that stare decisis matters, and that the Court should be careful not to rewrite the Fourth Amendment in a way that severely constrains the modern administrative state. Justice Sotomayor’s opinion is useful precisely because it offers an analytical compromise between these two arguments. To that end, one should not be surprised if Justice Sotomayor’s middle ground approach eventually attracts the support of her fellow Justices.

I. privacy as secrecy

One of the most enduring—and criticized—tests in Fourth Amendment jurisprudence arises out of another Supreme Court concurrence. The “reasonable expectation of privacy” test—the standard by which courts have long decided whether a Fourth Amendment “search” has occurred—was articulated not by Justice Stewart’s majority opinion in Katz v. United States, but by the concurring opinion authored by Justice Harlan.29 Katz held that the government’s placement of a listening and recording device outside a telephone booth in order to intercept a suspected gambler’s bets violated his Fourth Amendment rights.30 Prior to Katz, the Court had decided wiretapping cases by inquiring into whether the conduct violated protected property interests (and, in particular, whether the government technology intruded upon a particular structure, such as an apartment or house).31 The majority rule did away with this analysis, concluding that technology-assisted eavesdropping violated the telephone-caller’s rights, regardless of whether the detectaphone was placed inside or outside the telephone booth from which he placed his call.32

While supporting the majority’s contention that the Fourth Amendment “protects people, not places,”33 Justice Harlan went a step further by offering his own two-part test for deciding just how much protection those “people” deserved. “My understanding of the rule that has emerged from prior decisions is that there is a twofold requirement, first that a person have exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognize as ‘reasonable.’”34 Although offered only to clarify his “understanding” of previous cases, Justice Harlan’s analysis quickly filled the void left by the Court’s abandonment of its previous “physical invasion” and “tangible property” tests.35 The reasonable expectation of privacy test—at least on its face—offered lower courts and government investigators a memorable and ostensibly simple, two-pronged test that could be applied to numerous investigative techniques across multiple enforcement contexts. Moreover, even as the majority opinion denied it was doing so,36 the test affirmed the Court’s embrace of “privacy” as a constitutional concept, whose existence extended as far back as the seminal law review article written by Samuel Warren and Louis Brandeis, in which they had conceptualized privacy as a legal right and defined it as a “right to be left alone.”37

All tests have their limitations; Justice Harlan’s reasonable expectation of privacy test was no exception. Since its articulation, many observers (including authors of numerous Supreme Court dissents) have questioned the test’s descriptive accuracy,38 its circularity and subjectivity,39 and its disquieting normative implications.40

Indeed, four years after issuing his concurring opinion in Katz, Justice Harlan himself expressed discomfort with his own test in United States v. White.41 White followed a series of cases in which the government had used either an undercover officer or a cooperating witness to secure information from an unsuspecting defendant, culminating with the use of a secretly worn “wire” to transmit the conversation to the police as it occurred in real time.42White’s plurality opinion effectively placed both tactics—the use of the undercover informant generally, and the wearing of a transmittal device—outside the Fourth Amendment’s ambit. Since the defendant had already assumed the risk his compatriot would report information to the police, he also accepted the risk that the same turncoat would conspire with the government to record and transmit their conversations in real time.43 Society retained no expectation of privacy in information provided to third parties, be they friend, foe, or false friend. This proved too much for Harlan, who feared the Court was “saddling” society with pernicious expectations and risks.44 Notwithstanding these and other criticisms, the “assumption of risk” concept flourished over the next several decades, paving the way for a variety of procedures that most laymen would be surprised to learn are not “searches.”45

For most privacy and Fourth Amendment scholars, the Katz test has failed miserably in protecting the public’s privacy.46 Critics ascribe this failure to its emphasis on secrecy.47 To the extent that individuals fail to conduct their affairs in secret, they cede any objection to the government’s efforts to see, watch, or hear them.48 In a world that is increasingly networked and dependent on one’s partial disclosure of information to numerous commercial third parties, the protection once afforded by Katz appears quaint.49 As Professor Daniel Solove observes, life on the grid makes secrecy, and therefore privacy, all but impossible to secure.50

II. privacy as intimacy

As discussed in Part I, Justice Harlan’s reasonable expectation of privacy test in Katz eventually morphed into a dissatisfying secrecy test. As Professor Orin Kerr has argued in defense of the third-party doctrine, however, it is one thing to critique a test and quite another to articulate a viable alternative.51 Despite criticism, the Court has more or less adhered to Katz’s formulation, even as newer and more powerful instruments enable cheaper and more intrusive surveillance by the police and government agencies.

Jones thus provided the Court with the opportunity to rewrite Katz. As noted earlier, Judge Ginsburg’s opinion for the D.C. Circuit (rendered under a different caption, United States v. Maynard52) invoked the “mosaic theory”—according to which the investigative sum is greater than its constituent parts—that has now become the subject of much discussion among Fourth Amendment scholars.53 Tracking a person’s single journey from point A to point B may not be a search, Judge Ginsburg explained, but the same could not be said for the extended, multi-day surveillance of a person’s daily activities.54

For Katz’s strongest critics, mosaic theory evokes the possibility of erasing decades of jurisprudence and vastly transforming the Fourth Amendment’s reach.55 The theory has a number of drawbacks, however, as Jones itself illustrates.56 It does not easily guide future courts or enforcement agents in determining when GPS-assisted surveillance has triggered the Fourth Amendment’s various procedural requirements. Rather, it leaves the government guessing whether it has gone too far.

Justice Sotomayor’s concurrence improves upon the mosaic theory in two respects. First, she anchors her opinion in an alternate conception of privacy, conceptualizing it in terms of intimacy rather than secrecy. Second, she lays the groundwork for a multi-pronged test that lower courts might use in deciding what government activity is or is not a Fourth Amendment search.

Throughout her concurrence, Justice Sotomayor poses a series of questions that a hypothetical trial court judge might ask when reviewing a particular type of enforcement activity. In doing so, she queries “whether people reasonably expect that their movements will be recorded and aggregated in a manner that enables the Government to ascertain, more or less at will, their political and religious beliefs, sexual habits, and so on.”57 Thus, the problem with GPS monitoring is that it discloses highly intimate information. Later, Justice Sotomayor muses that it may be time for “our Fourth Amendment jurisprudence [to] cease[] to treat secrecy as a prerequisite for privacy.”58 She then follows up by stating, “I would not assume that all information voluntarily disclosed to some member of the public for a limited purpose is, for that reason alone, disentitled to Fourth Amendment protection.”59

Justice Sotomayor’s discussion shifts the definition of Fourth Amendment “privacy” away from secrecy and instead toward intimacy. The definition of this abstract idea lies far beyond the scope of this Essay.60 As used by Justice Sotomayor, however, the term “intimacy” appears to refer both to intimate relationships and to some notion of bodily integrity.61 This conception, though it has been criticized by scholars as either too narrow or overly abstract,62 represents a normative and descriptive improvement over Katz’sprivacy-as-secrecy conception. First, it offers more stable protection in a dynamic world. As technology changes, our shared understanding of what is and is not intimate is more stable than our understanding of what is and is not “secret.”

Second, “privacy as intimacy” better explains some of the Court’s prior Fourth Amendment jurisprudence, such as the protection that is afforded to the curtilage of a home but not to the open field.63 An emphasis on protecting intimacy provides a solid justification for the home’s status as “first among equals” in Fourth Amendment analysis.64 The home is the singular location in which we are most likely to engage in intimate activities.65 A rule that protects the home prophylactically protects intimacy.66

Outside the home, the protected veil of intimacy is more difficult to locate.67 It is wrong to say we cast off that veil whenever we act outside the home, but it is equally wrong to say that we retain it in the same manner. Dichotomous, categorical approaches (public versus private, workplace versus “personal,” metadata versus content) tend not to work very well.68 We thus find ourselves in need of an analytical tool to distinguish protected intimacy from unprotected intimacy.

Justice Sotomayor’s opinion contains the beginnings of such a framework. In explaining the problems with GPS monitoring, she observes that it generates a “precise, comprehensive record” of the person’s public movements, which in turn convey intimate information such as her “familial, political, professional, religious, and sexual associations.”69 Embedded in these observations are the components for a test that separates “intrusions on intimacy”—and therefore “searches”—from ordinary public observations—and therefore non-searches. Thus, going forward, a trial court might analyze an enforcement activity’s Fourth Amendment status by considering:

1. how comprehensively it generates information regarding an individual who is the target of such investigative activity; and

2.the degree of precision with which it has generated that information regarding a single target or group of targets.

The analysis does not end here. The issue is not simply that the government’s investigative activity generates a “substantial quantum of intimate information”70 about an individual, but that it does so in a way that is wholly unregulated by a “coordinate branch.”71 Justice Sotomayor’s reference to a “coordinate branch” is curious, as it suggests she is amenable to sources of oversight other than the “neutral and detached magistrate,” who has long served as the unchallenged hero of the Fourth Amendment canon.72 This more forgiving language hints at a pragmatic willingness to widen the Fourth Amendment’s regulatory tent.

Finally, as Justice Sotomayor points out, in addition to the lack of oversight, the secrecy of the government’s conduct matters as well.73 Secret, panoramic surveillance undermines democratic ideals by chilling speech and association.74 Accordingly, a lower court judging a particular type of activity might also consider:

3.the extent to which the activity in question proceeds surreptitiously and is regulated by a coordinate branch and therefore more or less prone to abuse.

Concededly, a framework such as the one above is sure to generate questions and criticisms. Reasonable people will disagree on terms like “comprehensiveness” and “precision,” and courts still will need to locate the proper “unit” of enforcement activity subject to this test. Do we look at the single subpoena, a day’s worth of surveillance, or the “whole” of the government’s investigation up to a given point in time? However vexatious these questions may seem in the abstract, there is no reason to believe that courts cannot answer them, or that the answers the Supreme Court and lower courts generate will leave us in a worse position than the one we appear to have reached under Katz.

III. an example: the white-collar problem in fourth amendment analysis

If the opinions issued in Jones should have struck fear in the heart of anyone, it was that of the white-collar criminal prosecutor. Imagine the standard fraud: a Ponzi schemer sells stakes in a fraudulent real estate scheme, and over the years, he sends his dupes quarterly statements purporting to tell them how well their investment is faring. During that time, he pockets their money, spends a fair amount of it on fancy clothing and restaurants, and feeds his growing gambling problem.

How does a prosecutor build a case against this schemer? How too does she determine if the schemer is acting on his own or working in concert with others? Presumably, at a bare minimum, she serves a grand jury subpoena on the schemer’s local bank, his credit card issuers, and the local telephone company. Oft-criticized cases decided decades ago, such as Smith,75 Miller,76 and Schultz,77 place this information easily within her grasp, regardless of whether she has “probable cause” or even “reasonable suspicion” that the defendant has committed any crime.78

How, then, might a privacy-as-intimacy framework treat the average white-collar case? Would a prosecutor suddenly find herself unable to assemble the evidence necessary to secure an arrest warrant? Viewed from the opposite perspective, would application of this new test still leave individuals prone to the very types of intrusions Justice Sotomayor viewed as potentially abusive in Jones?

Recall the framework: a district court applying a privacy-as-intimacy test might first consider the comprehensiveness of the government activity in question; she might then go on to consider its precision, including the extent to which it threatens to dredge up intimate details of the target’s life; finally, she should also consider whether the activity has been performed surreptitiously, as well as its corresponding lack of oversight by coordinate branches and consequent risk for abuse. Does a standard grand jury subpoena served on JPMorgan Chase for several months’ worth of historical bank records—or even a series of subpoenas, if we define the unit of enforcement activity expansively—transgress society’s reasonable expectation of privacy-as-intimacy?

Admittedly, the answer likely depends on one’s baseline. Compared to extended twenty-four-hour GPS monitoring, the grand jury subpoena for historical information seems rather tame. Subpoenas seeking several months’ worth of banking or credit card records provide far less comprehensive information than around-the-clock surveillance. We may become aware of disparate acts that one may deem “intimate,” but we are not as likely to penetrate a person’s “zone” of intimacy as we would be if we watched that person intently for twenty-four hours a day, weeks at a time.

Grand jury subpoenas also may provide “precise” information in some instances, but surely not in all. As for likelihood of abuse, the grand jury subpoena—although not particularly difficult to obtain or serve—offers marginally more oversight than the purely discretionary and surreptitious investigatory program.79 Accordingly, under a privacy-as-intimacy test, the grand jury subpoena seeking historical records arguably falls on the “non-search” side of a revised Fourth Amendment privacy test. It may well disclose the name of the target’s doctor (if, for example, she paid her doctor by check), or the restaurant where she ate dinner with her family (if she paid with her bank’s debit card). Still, the information collected is not so comprehensive and precise that we would conclude that a government agent has penetrated the target’s veil of intimacy outside the home.

Privacy scholars likely would disagree with the foregoing analysis,80 and perceive it cynically as the replacement of an old ineffective test with an equally bad one. Moreover, they might argue that this multi-pronged analysis invokes exactly that level of uncertainty Justice Scalia sought to avoid when he declined to parse the information obtained from a thermal imager in Kyllo v. United States.81 The locus of the search in Kyllo, however, permitted Justice Scalia this luxury, as the thermal imager was aimed at a home. Outside the home, however, bright-line rules are far more likely to yield either to standards or multi-pronged tests. Moreover, even those most skeptical of government power should welcome the emergence of a privacy-as-intimacy test. It would do away with the privacy-as-secrecy rubric and, with the guideposts suggested by Justice Sotomayor’s concurrence in Jones, it would focus the judiciary’s energies on those law enforcement activities that trigger the most alarm: dragnets that surreptitiously detect massive amounts of information with little to no oversight; extended surveillance of individuals as they go about their daily activities; and under-supervised use of cooperating informants and undercover agents, whose prolonged interaction with targets and their families all but assure the disclosure of intimate information. These are the very activities that are least regulated, most likely to convey comprehensive intimate information about our daily lives, and most susceptible of abuse.

At the same time, this middle-ground test would best ensure the prosecution’s access to those potent but more limited law enforcement devices that Professor William Stuntz long ago declared necessary in order to commence investigation of difficult-to-prove frauds.82 Although the Fourth Amendment presumptively requires a warrant and probable cause for “searches,” it does not go so far as to regulate all aspects of a criminal investigation.

Technology follows no ideology; it can cause as much harm in the criminal’s hands as it can in the hands of the police. It would be the ultimate irony if, in attempting to protect itself from “big government,” the Court left society more vulnerable to the corporate criminal. If Fourth Amendment law is, as Professor Kerr has argued, a form of “equilibrium-adjustment,” it would be a shame for the Court to adjust its jurisprudence in a direction that leaves the populace prone to more, and not less, harm.83


In recent times, the Supreme Court has been criticized for its “proliferation of separate opinions,”84 as they allegedly confuse the populace and weaken the rule of law.85 But Justice Sotomayor’s concurrence in Jones demonstrates their potential long-term value.86 She embraces the majority’s view that physical intrusions on property implicate the Fourth Amendment, but then uses her concurrence to express the emerging consensus that the reasonable expectation of privacy and third-party doctrines have outlived their usefulness. Drawing on the common-sense outlook that resonates with both legal and lay audiences, she has laid a foundation upon which later courts may develop a more fulsome conception of privacy and a workable framework for protecting it.

Miriam H. Baer is an Associate Professor of Law at Brooklyn Law School. She holds a J.D. from Harvard Law School and A.B. from Princeton University. For helpful comments and conversations on the topic, the author gratefully thanks her co-panelists, Rachel Barkow and Bennett Capers; as well as Kate Stith, Orin Kerr, and Susan Herman, who provided helpful feedback and comments; and Shannon Daugherty and Joanna Menillo, who provided excellent research assistance on this project.

Preferred citation: Miriam H. Baer, Secrecy, Intimacy, and Workable Rules: Justice Sotomayor Stakes Out the Middle Ground in United States v. Jones, 123 Yale L.J. F. 393 (2014), -and-workable-rules.