Carpenter Fails to Cabin Katz as Miller Grinds to a Halt: Digital Privacy and the Roberts Court

Marc Rotenberg President, Electronic Privacy Information Center and Adjunct Professor, Georgetown University Law Center

When the U.S. Supreme Court agreed to hear the appeal of Timothy Carpenter, the excitement in the privacy world was widespread. Here was the case that would take the Fourth Amendment into the digital age, the opportunity to put constitutional limits on the collection of location information generated by cell phones, the chance to solidify two recent and favorable decisions by the Court. Perhaps the stakes were not quite as high as the battle between The Machine and Samaritan in the final season of Person of Interest,[1] but they were close.

The outcome did not disappoint. Chief Justice Roberts said “we hold that an individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through”—wait for it—“CSLI [cell site location information.]”[2] Rejecting the third-party doctrine, which provided that the Fourth Amendment ends where third parties begin, the chief justice wrote, “After all, when [Smith v. Maryland] was decided in 1979, few could have imagined a society in which a phone goes wherever its owner goes, conveying to the wireless carrier not just dialed digits, but a detailed and comprehensive record of the person’s movements.” He continued, “There is a world of difference between the limited types of personal information addressed in Smith and [United States v. Miller] and the exhaustive chronicle of location information casually collected by wireless carriers today.”[3] The Court emphasized that “a person does not surrender all Fourth Amendment protection by venturing into the public sphere.”[4] And therefore “when the Government accessed CSLI from the wireless carriers, it invaded Carpenter’s reasonable expectation of privacy in the whole of his physical movements.”[5]

Moreover, Chief Justice Roberts drew no distinction between whether the government deployed its own technology, such as a GPS tracking device, or sought to access that same information from a wireless carrier. “In fact, historical cell-site records present even greater privacy concerns than the GPS monitoring of a vehicle we considered in Jones,” the Court wrote.[6] “A cell phone faithfully follows its owner beyond public thoroughfares and into private residences, doctor's offices, political headquarters, and other potentially revealing locales. Accordingly, when the Government tracks the location of a cell phone it achieves near perfect surveillance, as if it had attached an ankle monitor to the phone’s user.”[7]

“Virtually any activity on the phone generates CSLI, including incoming calls, texts, or e-mails and countless other data connections that a phone automatically makes when checking for news, weather, or social media updates. Apart from disconnecting the phone from the network, there is no way to avoid leaving behind a trail of location data,” Chief Justice Roberts added.[8] “In light of the deeply revealing nature of CSLI, its depth, breadth, and comprehensive reach, and the inescapable and automatic nature of its collection, the fact that such information is gathered by a third party does not make it any less deserving of Fourth Amendment protection.”[9] Dissenting opinions were filed by Justices Kennedy, Thomas, Alito, and Gorsuch.

Henceforth, law enforcement access to the location records will be subject to a Fourth Amendment standard that is higher than the standard established by Congress for the so-called “2703(d) orders” in the 1994 amendments to the federal Wiretap Act.[10] For Mr. Carpenter and the owners of the 396 million cell phone accounts (in a nation of only 326 million people),[11] the outcome is good news. Everyone now has constitutional protections in location data that they did not have before Carpenter was decided. But as for the Fourth Amendment in the digital age and the famous Katz decision, with its “reasonable expectation of privacy” test, the fun has just begun. Four detailed dissenting opinions, 119 pages, 160 references to “privacy,” and a newly-confirmed justice guarantee that. So, too, does new technology.

Many looked to the Carpenter decision to revise the third-party doctrine. That has not happened. And the prospects are real that in future cases focused on police access to location data, those in possession of personal data will require a judicial warrant before disclosure may occur. But somewhat unexpectedly, the Court has also raised new questions about the future of Katz, the case that established the “reasonable expectation of privacy” test for Fourth Amendment searches. That suggests that even as the third-party doctrine is updated for the digital age it may be necessary also to reexamine the foundations of Fourth Amendment privacy.

This article outlines a post-Carpenter “Progressive Constitutional” approach to the Fourth Amendment that borrows from the seminal wire-tapping case Olmstead v. U.S.,[12] an important nineteenth century case Boyd v. United States,[13] and the opinion of Justice Gorsuch in Carpenter. I suggest that Congress now has an opportunity to update federal privacy law, providing greater clarity for digital searches after the Carpenter decision. And following related developments with communications privacy law, I conclude that even the collection of location data should not be assumed. In some circumstances, the Court could one day hold, it may be impermissible.

I. The Fourth Amendment Collision with Technology

For almost a hundred years, the Court has struggled with the question of what to do when the text of the Fourth Amendment collides with new technology. The most famous and still the most important decision was also the first— Olmstead v U.S.[14] “Big Ray” Olmstead was before the Supreme Court because federal agents tapped the phone lines of his illegal bootlegging operation without a search warrant.[15] The Supreme Court held that the warrantless interception of telephone communications of Olmstead’s operation was not a search and therefore permissible under the Fourth Amendment. Chief Justice Taft, relying heavily on a common-law trespass view, concluded that the Fourth Amendment did not protect one who “installs in his house a telephone instrument with connecting wires [because he] intends to project his voice to those quite outside, and [therefore] the wires beyond his house and messages while passing over them are not within the protection of the Fourth Amendment.”[16]

The Olmstead case had several interesting dissents. Justice Holmes famously opined “it is a less evil that some criminals should escape than that the Government should play an ignoble part.”[17] The reference was to the fact that the federal agents violated a Washington state law against wiretapping—“a dirty business,” said Justice Holmes—when they gathered the evidence. Breaking the law to enforce the law, Justice Holmes explained, was not the way to go.

Justice Butler, in a dissent that may someday be cited by Justice Gorsuch, observed that the “contracts between telephone companies and users contemplate the private use of the facilities employed in the service. The communications belong to the parties between whom they pass.”[18] We might describe the Butler view as a defense of “bailment.” Or we could say he was describing an expectation of privacy. More on that later.

But the Olmstead dissent that provided the basis for the Supreme Court’s decision forty years later in Katz v. United States and ushered the text of the Fourth Amendment into the modern age was that of Justice Brandeis. Well before cloud-computing services, Justice Brandeis observed,

the progress of science in furnishing the Government with means of espionage is not likely to stop with wiretapping. Ways may someday be developed by which the government, without removing papers from secret drawers, can reproduce them in court, and by which it will be enabled to expose to a jury the most intimate occurrences of the home.[19]

“What to do?” as Justice Gorsuch would ask ninety years later, when the Fourth Amendment confronts new technology. Justice Brandeis began at the beginning. Citing Chief Justice Marshall in McCullough v. Maryland, he explained, “We must never forget that it is a constitution we are expounding”[20] “Its general principles would have little value, and be converted by precedent into impotent and lifeless formulas. Rights declared in words might be lost in reality.”[21]

Justice Brandeis turned next to Boyd, an important nineteenth century case that held that the compelled production of documents violated both the Fourth and Fifth Amendments. Justice Bradley explained in that case, in the passage quoted by Brandeis in Olmstead (and referenced later in Carpenter):

The principles laid down in this opinion affect the very essence of constitutional liberty and security. They reach farther than the concrete form of the case then before the court, with its adventitious circumstances; they apply to all invasions on the part of the government and its employees of the sanctity of a man’s home and the privacies of life. It is not the breaking of his doors and the rummaging of his drawers that constitutes the essence of the offense; but it is the invasion of his indefeasible right of personal security, personal liberty, and private property, where that right has never been forfeited by his conviction of some public offense, it is the invasion of this sacred right which underlies and constitutes the essence of Lord Camden’s judgment.[22]

Justice Brandeis also observed that if the government must obtain a warrant to open the postal mail to view a single letter, as in Ex parte Jackson,[23] then it must certainly require one for the far more intrusive act of intercepting and recording telephone communications.

The evil incident to invasion of the privacy of the telephone is far greater than that involved in tampering with the mails. Whenever a telephone line is tapped, the privacy of the persons at both ends of the line is invaded and all conversations between them upon any subject, and, although proper, confidential and privileged, may be overheard. Moreover, the tapping of one man’s telephone line involves the tapping of the telephone of every other person whom he may call or who may call him.[24]

Rejecting the property-based view of the Fourth Amendment and providing perhaps the first opinion in cyberlaw, Justice Brandeis concluded “Applying to the Fourth and Fifth Amendments the established rule of construction, the defendants’ objections to the evidence obtained by wiretapping must, in my opinion, be sustained. It is, of course, immaterial where the physical connection with the telephone wires leading into the defendants’ premises was made.”[25]

In the Olmstead dissent, Justice Brandeis accomplished two remarkable feats: he applied the Fourth Amendment to new technology, and he set the cornerstone of Progressive Constitutionalism, the view that the Constitution should adapt to the times. It took only forty years before the Supreme Court understood all of this.

But before we tell the story of Olmstead’s vindication, it is important to make two other points about the history leading up to Carpenter. First, the Taft majority and the Brandeis dissent introduced a sharp split in the application of the Fourth Amendment to new technologies. Chief Justice Taft had drawn a bright line at the home. Justice Brandeis viewed the home as largely irrelevant, at least as to the flow of electronic information containing personal data. Not only were the two doctrines difficult to reconcile, descriptively they imagined two different worlds, one of fences and property lines, the other of wires and messages racing through the ether. Chief Justice Taft’s view offered no obvious path for the Fourth Amendment to the modern age.

But that did not mean that one side necessarily favored privacy more than the other. Chief Justice Taft did not dismiss the privacy interest before him. His solution was to get Congress on the playing field. He wrote, “Congress may, of course, protect the secrecy of telephone messages by making them, when intercepted, inadmissible in evidence in federal criminal trials by direct legislation, and thus depart from the common law of evidence.”[26] And in fact, Congress took up the invitation in 1934 and enacted § 605, a provision of the Communications Act intended to safeguard communications privacy.[27] That provision, now recast as § 222,[28] reappears in Carpenter, as does the Boyd opinion, the Brandeis dissent, and the recommendation that Congress take action. To understand Carpenter, we must understand Katz. And to understand Katz we must understand Olmstead.

II. A Reasonable Expectation of Privacy

It is conventional wisdom that the Supreme Court in Katz reversed Olmstead and adopted the Brandeis dissent when it held that a warrant was required to intercept a telephone communication that took place at a payphone in Los Angeles. But that reading to me has never seemed correct. The Brandeis dissent in Olmstead was never simply about the warrant requirement. Justice Brandeis also viewed the government conduct as an offense against the Fifth Amendment. His opinion is grounded in the famous 1890 case Boyd v. United States,[29] which makes several cameos in Carpenter, and raised the very real possibility that even with a warrant, the evidence would simply be beyond the reach of government. Indeed, under the “mere evidence” rule, only instrumentalities, fruits of the crime, and contraband could be searched and seized. Mere evidence, such as records of communications, could not be seized. That was the significance of the Boyd reference in the Brandeis opinion. And it was not until 1967 that the Court formally abandoned the rule. But the textualists and the originalists should have objected, because the text is clear: no person “shall be compelled in any criminal case to be a witness against himself.”[30] The Brandeis dissent, like the Court’s opinion in Boyd, grounded what we now call Progressive Constitutionalism in sturdy originalism.

In the same year that the Court abandoned the mere evidence rule, the Court held that a warrant was required for the interception of telephone communications. And in a companion case, Berger v. New York,[31] that has never received the love that Katz did, the Court also held that a New York state law that established some limitations on wiretapping did not go far enough.

But many of the key elements in the Brandeis Olmstead dissent did not survive Katz. There were no references to the scope of surveillance (there were lots of payphones in L.A. at the time), the Boyd decision (except for a contrary reference in Justice Black’s dissent), the significance of the Fifth Amendment, or even the need to limit search in space and time. The Court in Katz says it overturned Olmstead, but it nowhere actually discusses Justice Brandeis’s critical dissent explaining why the original case was wrongly decided. Instead we ended up with the holding “privacy protects people not places” and the famous Harlan concurrence setting out the two-factor test for the reasonable expectation of privacy.[32]

Before we join the Carpenter dissenters and pummel the logic in Katz, we need to review two recent decisions of the Roberts Court that underpin the majority opinion in Carpenter.

A. The Shadow Majority in Jones

              In 2012, the Court held in a unanimous opinion that the warrantless surveillance of a car with a GPS-tracking device was unconstitutional.[33] The outcome was striking not so much for the tally but for the three distinct opinions that each conveyed a different theory of how best to decide the case. Justice Scalia, writing for a five-member majority, grounded his view in a common-law trespass notion of the Fourth Amendment, much like Chief Justice Taft had in Olmstead. The difference of course was that the police had placed the GPS tracking device on the vehicle of the target, and that constituted the violation of the eighteenth-century text of the Constitution. Justice Scalia, who was joined by Chief Justice Roberts and Justices Kennedy, Thomas, and Sotomayor, did not exactly reject the Katz reasonable expectation of privacy formulation. He simply said that “18th-century guarantee against unreasonable searches . . . must provide at a minimum the degree of protection it afforded when it was adopted.”[34] Indeed, Justice Scalia went to some pains to leave Katz in place. “[U]nlike the concurrence, which would make Katz the exclusive test, we do not make trespass the exclusive test. Situations involving merely the transmission of electronic signals without trespass would remain subject to Katz analysis.”[35]

But the concurrence in Jones, authored by Justice Alito, and joined by Justices Ginsburg, Breyer, and Kagan, did fully embrace Katz. As Justice Alito wrote at the time:

This case requires us to apply the Fourth Amendment’s prohibition of unreasonable searches and seizures to a 21st-century surveillance technique, the use of a Global Positioning System (GPS) device to monitor a vehicle’s movements for an extended period of time. Ironically, the Court has chosen to decide this case based on 18th-century tort law. . . .

I would analyze the question presented in this case by asking whether respondent’s reasonable expectations of privacy were violated by the long-term monitoring of the movements of the vehicle he drove.[36]

In other words, according to the concurrence, Katz should control the outcome.

For those who are keepings score, it would appear that we have unanimity on the outcome, with five votes in favor of a property-based view of the Fourth Amendment and four votes for the Katz reasonable-expectation-of-privacy view. But this is where Jones gets interesting, because Justice Sotomayor cast two votes. Justice Sotomayor did not simply sign-on to Justice Scalia’s opinion for the majority. She wrote a separate concurrence, in which she went further than team Katz. Siding with Justice Scalia, she explained, “Katz’s reasonable-expectation-of-privacy test augmented, but did not displace or diminish, the common-law trespassory test that preceded it.”[37]

Justice Sotomayor also set up the key question that would be before the Court in Carpenter when she wrote in concurrence that it “may be necessary to reconsider the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties.”[38] As she explained, the “approach is ill suited to the digital age, in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks.”[39] Perhaps anticipating a case such as Carpenter, Justice Sotomayor warned in Jones, “GPS monitoring generates a precise, comprehensive record of a person’s public movements that reflects a wealth of detail about her familial, political, professional, religious, and sexual associations.”[40] Justice Sotomayor quoted Justice Marshall’s dissent in Smith v. Maryland: “Privacy is not a discrete commodity, possessed absolutely or not at all. Those who disclose certain facts to a bank or phone company for a limited business purpose need not assume that this information will be released to other persons for other purposes.”[41]

The four votes in the Alito concurrence and the Sotomayor concurrence together constituted five votes in favor of the view that Katz controlled the outcome in the GPS tracking case. But the majority opinion by Justice Scalia said otherwise. Hence the case resulted in a majority for the property-based view of the Fourth Amendment and a “shadow majority” for the Katz view.

III. The Cellphone as Extension of Human Anatomy

So, maybe it was an overstatement above to suggest that a 9-0 vote to grant a suppression motion by the Supreme Court in 2012 was not remarkable. But after a similar outcome in the 2014 case Riley v. California,[42] unanimous verdicts by the Court in digital privacy cases were becoming commonplace. In Riley the Court considered whether the search of a cell phone incident to an arrest required a warrant. In previous search-incident-to-arrest cases involving wallets and cigarettes packs, the Court had rejected the warrant requirement. But as just about every amici in Riley contended, cell phones are “different.” Not only do they contain vast repositories of personal data, they also provide access to cloud-based service and even unlock homes and cars.[43] Can your cigarette pack do that?

The Court agreed that cell phones were different and also that they were everywhere. And to drive the point home, Chief Justice Roberts invoked the “proverbial visitor from Mars” to observe that cellphones could easily be viewed as an “important feature of human anatomy.”[44] Justice Roberts described the far-reaching capabilities of cell phones and noted that “[h]istoric location information is a standard feature on many smart phones and can reconstruct someone’s specific movements down to the minute, not only around town but also within a particular building.”[45] And there was a big shout-out for Boyd watchers. “Modern cell phones are not just another technological convenience. With all they contain and all they may reveal, they hold for many Americans ‘the privacies of life.’”[46]

Justice Alito joined the majority in Riley, stating:

we should not mechanically apply the rule used in the predigital era to the search of a cell phone. Many cell phones now in use are capable of storing and accessing a quantity of information, some highly personal, that no person would ever have had on his person in hard-copy form. This calls for a new balancing of law enforcement and privacy interests.[47]

But Justice Alito, who had warned in Jones that Congress may be better equipped to address the challenges of the digital age, also wrote in concurrence that,

it would be very unfortunate if privacy protection in the 21st century was left primarily to the federal courts using the blunt instrument of the Fourth Amendment. Legislatures, elected by the people, are in a better position than we are to assess and respond to the changes that have already occurred and those that almost certainly will take place in the future.[48]

Siding with the Court but also looking to Congress, Justice Alito set out the view in Riley that many anticipated he would follow in Carpenter.

IV. Back to Carpenter

And so when the Supreme Court granted certiorari in Carpenter in January 2018, following the two 9-0 outcomes in Jones and Riley, the privacy world was abuzz. Would the Court overturn the third-party doctrine as Justice Sotomayor suggested in Jones? Would the Court maintain its unanimous voting record on emerging privacy issues, a remarkable outcome made clear in Jones and Riley? And would anyone know what the acronym “CSLI” stood for?

Perhaps we should begin by noting that binary star systems are stable over time because celestial objects exert constant gravitational forces that tend toward an equilibrium. And so, it is possible for planets to orbit a binary star system even though there are multiple gravitational forces. Unfortunately, Supreme Court doctrine, even with the twin forces of Katz and trespass law, is not prone to equilibrium. And so, the hope that Carpenter would provide either a stable outcome or a grand synthesis for digital privacy was not to be.[49] The fissures in Jones opened up with significant consequence in Carpenter, suggesting that the contours of future privacy cases are far from clear.

A. The Majority – Get a Warrant

In Carpenter, the Supreme Court holds that “an individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through CSLI.”[50] As applied to the facts before the Court, a request for seven or more days of cell-site records triggers constitutional scrutiny. The search pursuant to § 2703(d) is unlawful and the evidence must be excluded.

To reach the result, Chief Justice Roberts reconciles two lines of cases—the first concerns a person’s expectation of privacy in their physical location, the second concerns the records that are maintained by so-called third parties. From Jones we establish that a person does have an expectation of privacy in their location data, but from Smith and Miller we are told that the expectation of privacy is extinguished when the records are held by third parties. A simple way to understand the outcome in Carpenter is to say that there is now a location data exception to the third-party doctrine.

But much has also changed since Smith and Miller were decided. The Chief Justice, drawing on the Jones and Riley opinions, makes this clear:

The question we confront today is how to apply the Fourth Amendment to a new phenomenon: the ability to chronicle a person’s past movements through the record of his cell phone signals. Such tracking partakes of many of the qualities of the GPS monitoring we considered in Jones. Much like GPS tracking of a vehicle, cell phone location information is detailed, encyclopedic, and effortlessly compiled . . . .

. . . .

. . . [W]hen Smith was decided in 1979, few could have imagined a society in which a phone goes wherever its owner goes, conveying to the wireless carrier not just dialed digits, but a detailed and comprehensive record of the person’s movements.[51]

Chief Justice Roberts’s opinion is remarkable not only for describing the vast change in scale and scope of data collection made possible by digital technology, but also recognizing the ability for law enforcement to “travel back in time to retrace a person’s whereabouts,” because time-stamped location records exist in multiple dimensions, placing people in particular places at particular times.[52] The Brandeis dissent in Olmstead, which contrasted the search of communications channels with the search of a single physical object, first identified the unbounded character of cyber searches. But it was Chief Justice Roberts in Riley who recognizes that in the digital age, stored data also moves time backward.[53]

A second key insight is that a search through cell history data is boundless and requires no individual suspicion. As Chief Justice Roberts explains, “police need not even know in advance whether they want to follow a particular individual, or when. . . . Only the few without cell phones could escape this tireless and absolute surveillance.”[54] And so, we see the outcome: “The Government’s position fails to contend with the seismic shifts in digital technology that made possible the tracking of not only Carpenter’s location but also everyone else’s, not for a short period but for years and years.”[55]

But Chief Justice Roberts stops short of overturning Smith and Miller, and it is not entirely clear why. Much of his opinion makes clear that in the digital world there is little sense in which individuals “voluntarily disclose” personal information to others in the way that Chief Justice Taft had described telephone calls as “broadcast” to the world. Many of these records are generated by the use of the service. Chief Justice Roberts also states that location data about where individuals travel “implicates basic Fourth Amendment concerns about arbitrary government power much more directly than corporate tax or payroll ledgers.”[56]

B. The Dissents

There are four dissents in Carpenter, with several justices signing on to the dissents of others. Justice Kennedy expresses concern about the impact of the Court’s decision on police practice and also suggests that the privacy interest in cell-site location information in Carpenter is simply less than the GPS data in Jones.[57] But on the technology the chief gets the better of the argument—the Kennedy opinion does not reflect the reality that cell phones are pinged, i.e., location is established, routinely without any action by the users, as Justice Sotomayor had also observed in her Jones concurrence. To add a layer to the creepy factor, the mics and cameras on cell phones can also be remotely activated. While such real-time investigative technique should certainly be subject to constitutional review, it is not science fiction to recognize that the cell phone is more than a tracking device. It is also a remote listening device.

Justice Thomas lets loose on Katz and frankly makes a good argument.[58] The problems of the Katz doctrine are well known, and Justice Thomas marshals the forces. He also places understandable weight on the language of the phrase in the Fourth Amendment regarding their “persons, papers, and effects.” For the textualist, the third-party doctrine is established long before Miller.

Justice Alito, who might have been expected to concur in the outcome but write separately, chose a different course.[59] In his view, the subpoena process is so well established that any effort to modify the third-party doctrine will lead to confusion and chaos. He writes, “We will be making repairs—or picking up the pieces—for a long time to come.”[60] But Alito, as he did in Jones and Riley, also looks to Congress to solve these challenges: “legislation is much preferable to the development of an entirely new body of Fourth Amendment caselaw for many reasons, including the enormous complexity of the subject, the need to respond to rapidly changing technology, and the Fourth Amendment’s limited scope.”[61] And he rightly notes that Congress can also reach the challenges from the use of personal data by the commercial sector:

The Fourth Amendment restricts the conduct of the Federal Government and the States; it does not apply to private actors. But today, some of the greatest threats to individual privacy may come from powerful private companies that collect and sometimes misuse vast quantities of data about the lives of ordinary Americans.[62]

And in fact, federal wiretap law has often regulated the conduct of both the government and private actors.

C. The Gorsuch Concurring Dissent

Among the dissents, the most interesting is from Justice Gorsuch.[63] It is a concurrence in every way but the title. Not only does Justice Gorsuch believe the search of cell-site records was unlawful, he would go further than the Court and overturn the third-party doctrine as many had urged. Justice Gorsuch justifies the designation “dissent” because Carpenter failed to raise these arguments on appeal, but the message is clear. If there was a “shadow majority” in Jones, there were six votes in Carpenter for the proposition that the search was unlawful.

More interesting is Justice Gorsuch’s efforts to imagine a world without Smith and Miller, cases that let “the government search almost whatever it wants whenever it wants.”[64] Justice Gorsuch, like Justice Thomas, is also not happy with Katz as the remaining foundation, but he is also not willing to ignore the growing impact of digital surveillance technologies on the rights of Americans. The question is what to put in its place. Justice Gorsuch provides an answer.[65]

First, the courts should recognize that when we turn over our personal possessions to others—the essence of the third-party doctrine—we do in fact have an interest in what happens next. Justice Gorsuch describes this as a bailment. In his Olmstead dissent, Justice Butler called it a contract. Others have called it a fiduciary obligation. Second, our interest in our personal data held by others need not be absolute to establish a legal interest. Third, we may be able to avoid the circularity of Katz by looking for concrete signs that society has in fact deemed certain activities as private. That is how a federal statute comes into play in this case about the scope of the Fourth Amendment. Section 222 establishes some control for the use of personal data held by the telephone company. For Justice Gorsuch that is enough to establish a privacy interest. Fourth, the inquiry into positive law is an upward ratchet. Just because the government engages in the conduct does not establish that the conduct is permissible. And this constitutional floor applies as well to subpoenas. And perhaps of greatest interest, Judge Gorsuch also signals an interest in a robust understanding of the Fifth Amendment as applied to digital data: “there is substantial evidence that the privilege against self-incrimination was also originally understood to protect a person from being forced to turn over potentially incriminating evidence.”[66] That was key to the Brandeis dissent in Olmstead, but disappeared in Katz, and could now reemerge after Carpenter.

D. The Smith and Miller Incantations

Both the majority and dissents restate Smith and Miller as settled law, which at the time of the decision was true but also incomplete. First, it bears noting that both decisions of the Supreme Court were followed by acts of Congress that did indeed establish privacy safeguards for records held by third parties. The Right to Financial Privacy Act of 1978[67] was the response of Congress to the Miller decision. The Stored Communications Act of 1986[68] was the response to Smith.

Perhaps it would surprise the dissenters to learn that those in possession of records of others would want clarity as to the circumstances when it is appropriate to release personal information to the government. Whether understood as a fiduciary obligation, a bailment, or simply fair play, the Court’s conclusion that the Fourth Amendment does not extend to third parties has not, in practice, ended the discussion over the circumstances when third parties would disclose information in their possession to a government agent.[69] In fact, and remarkably, the American Telephone and Telegraph company filed an amicus brief in the Olmstead case, arguing for the warrant requirement. And many of the arguments put forward by AT&T back in the day were adopted by Justice Brandeis in his dissent.

So, the dissenters’ assumption that third-party doctrine provides a bright-line rule tells only part of the story. In practice, those third parties still need legal rules to guide their conduct. And the dissents in Smith and Miller deserved more attention in Carpenter. As noted above, Justice Sotomayor’s concurrence in Jones draws heavily on Justice Marshall’s assumption of risk analysis in Smith, a point that was essentially made also by both Justice Gorsuch and Justice Alito in their dissents in Carpenter. The idea that individuals “voluntarily” disclose their personal data to third parties so that it can be used by others for unrelated purposes is more fiction than fact.

But there was a second dissent in Smith that also deserved more attention in Carpenter than it received. In Smith, Justice Stewart said that the protection for the content of a communication should extend also to the records associated with the communications.

The numbers dialed from a private telephone—although certainly more prosaic than the conversation itself—are not without “content.” Most private telephone subscribers may have their own numbers listed in a publicly distributed directory, but I doubt there are any who would be happy to have broadcast to the world a list of the local or long-distance numbers they have called. This is not because such a list might in some sense be incriminating, but because it easily could reveal the identities of the persons and the places called, and thus reveal the most intimate details of a person's life.[70]

Justice Stewart’s analysis of the challenge in the digital age is relevant for at least two reasons. First, he makes clear that data, as much as content, is significant. Second, he charts a path from Katz that side steps the third-party doctrine. It is less significant where the records are stored than where they originate: “The information captured by such surveillance emanates from private conduct within a person’s home or office—locations that without question are entitled to Fourth and Fourteenth Amendment protection.”[71]

E. What Would Scalia Do?

Justice Scalia’s views of the Fourth Amendment loomed large in several of the dissents. Justice Thomas quoted Scalia opinions at length, as did Justice Gorsuch. But one has to ask: What would Justice Scalia do if he were still on the Court? It is not at all obvious he would have joined the dissenters. It was Justice Scalia writing for the Court in 2001 who held that thermal imaging devices required a warrant. “This assures preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted,” he wrote in Kyllo.[72] And it was Justice Scalia who famously dissented in Maryland v. King, the DNA search case, writing:

Today’s judgment will, to be sure, have the beneficial effect of solving more crimes; then again, so would the taking of DNA samples from anyone who flies on an airplane (surely the Transportation Security Administration needs to know the “identity” of the flying public), applies for a driver’s license, or attends a public school. Perhaps the construction of such a genetic panopticon is wise. But I doubt that the proud men who wrote the charter of our liberties would have been so eager to open their mouths for royal inspection.[73]

And in Jones, Justice Scalia did not argue that Katz was not good law. His point was that the property-based view provided a “minimum” standard for the Fourth Amendment and helped ensure that the reasonable-expectation-of-privacy analysis did not dip below this baseline.

So, it may be worth pushing against the premise in several of the dissents that Justice Scalia would have joined them in rejecting Katz. And it is most certainly worth noting that Justice Alito mischaracterized Justice Brandeis when he wrote in his dissent that “even Justice Brandeis—a stalwart proponent of construing the Fourth Amendment liberally—acknowledged that ‘under any ordinary construction of language,’ ‘there is no “search” or “seizure” when a defendant is required to produce a document in the orderly process of a court’s procedure.”[74] Justice Brandeis made the opposite point in Olmstead. “Time and again, this Court in giving effect to the principle underlying the Fourth Amendment, has refused to place an unduly literal construction upon it,” Justice Brandeis explained. “No court which looked at the words of the Amendment, rather than at its underlying purpose, would hold, as this Court did in Ex parte Jackson . . . that its protection extended to letters in the mails.”[75]

V. Next Steps

A. Congress

One immediate consequence of the Court’s decision in Carpenter is that the “2703(d) order,” the process for obtaining cell-site records from telephone companies, is no longer good law. That means that Congress will almost certainly be asked by the Department of Justice and the telephone companies to enact a new standard that follows Carpenter. The interesting question is whether Congress will do more. It would be a mistake to assume that the “Carpenter fix” is simply an adjustment to the Fourth Amendment setting in the Stored Communications Act.

The Electronic Communications Privacy Act of 1986,[76] which established the 2703(d) order, is in need a major upgrade.[77] The commercial use of communications data has increased in ways that could not have been imagined when e-mail first arrived on the scene. Law enforcement has many more ways to access private communications than in the past. And the absence of robust encryption leaves communications in the United States subject to attack by foreign adversaries. Carpenter should lead to public hearings that include a broad examination of the full range of new threats to online privacy.

Congress should also recognize that effective privacy law typically establishes multiple firewalls to ensure accountability. The federal Wiretap Act of 1968, for example, established a Fourth Amendment standard for the interception of electronic communications. But it also put in place limits on the duration of surveillance, established procedures for minimization, designated predicate crimes, required judicial determinations for extensions and target notification, and imposed substantial public reporting requirements.[78] These are the elements of modern privacy law, available to Congress, as it undertakes its review post-Carpenter.

B. The Courts

Justice Alito was almost certainly correct when he said that the decision will cause confusion among lower courts. The third-party doctrine, right or wrong, provided a bright line that made easy the application of Fourth Amendment challenges to records held by third parties. The Court has moved the line with Carpenter, and the settling point is not clear. Many records include location data of the type found in cell site records.[79] It appears likely that Carpenter II is in the Court’s near future.

Justice Gorsuch has helpfully provided guideposts that may give more clarity for the Katz test when that case returns to the Court. I would not ignore his bailment theory that follows from the Butler dissent in Olmstead. And I would point to the interest in positive law—objective indicators that we as a society value privacy—to help clarify our contemporary understanding of privacy.[80] It is likely that we will uncover acts of Congress responding to invitations from the courts to establish new protections in the digital age that then help the courts see the objective expectation of privacy in our modern society.

But if the aim is to further the project of Progressive Constitutionalism, we should go back to Olmstead and imagine a doctrine that reflects less of the circularity of Katz and more of the interpretive guidance of Justice Brandeis, incorporating the opinions in Boyd and Ex parte Jackson. This is the recovered history now made relevant with Katz teetering on the brink. Surveillance unbounded from space and time is different from a physical search that exists at a moment in time. But that does not diminish the constitutional claim. It amplifies it. And perhaps the right of the people should inhere in their persons. It has always seemed odd to me that the Fourth Amendment, alone among the amendments, ascribes personal rights to property interests. Perhaps this was the Framers’ best understanding of one’s persona in the eighteenth century. We are those things we keep in homes, those papers we choose to possess, the daily activities we record in our journals and our business records. And as against the government, to be secure in our private lives, we must ensure oversight. But in the twenty-first century, we are now also the places we visit, the texts we send, the people we are with, the things we seek—the ephemeral now made permanent in our digital age. Although it is correct that the cell-cite location information concerning Mr. Carpenter resided with third parties, those records could not exist but for the activities of Mr. Carpenter that caused the records to be created. And that is true for all cell-phone users in the United States. Those records exist because of us; and if companies choose to retain them, we should have some say over how they are used and when they are disclosed to others.

I doubt the framers would disagree.

VI. Concluding Thought: Data Retention, Positive Law, and the Future of Privacy

Finally, there is no necessary reason for telephone companies to retain cell-cite location information. For many years, including the year when Smith v. Maryland was decided, telephone services were billed as a flat-rate utility and call set-up information was not generated or retained. The cell tower location information generated by the network today is necessary in the moment to connect the device to the cell network and to provide the user with information about location. The data may also be useful to evaluate a service’s quality and decide where to place additional cell towers. But almost all other uses of the data, generated solely by the users’ private activities, raise troubling privacy concerns. Should telephone companies make use of this data to target services at the consumers, making every act subject to scrutiny? When the telephone companies transfer aggregate phone data to retailers trying to measure population density, is the technique for deidentification robust? How secure are the detailed records of those 396 million cellphone account holders from criminal hackers and foreign governments? Under what circumstances may the telephone companies disclose this data to law enforcement? The Court answered that last question in Carpenter, but it is likely not the only constitutional concern present.

Digital technologies have created a vast data retention dynamic. This dynamic requires some legal scrutiny. In the European Union, an initial effort to harmonize the data-retention laws of member states eventually settled on two years for telephone record information. That conclusion was subject to fierce political opposition in the European Parliament and legal judgements by courts across Europe that found the routine retention of data about private life unnecessary and disproportionate. Eventually, the Court of Justice of the European Union took up the matter and concluded that the retention of phone records, of the type at issue in the Carpenter case, was a violation of fundamental rights.[81] In other words, today telephone companies in Europe are simply not permitted to keep five years of cell-cite information because of constitutional limitations in EU law.

Data retention was not before the U.S. Supreme Court in Carpenter, but perhaps it should have been. There is an inversion taking place in the realm of law enforcement. Increasingly digital data is building new mountains of evidence that will provide the basis for millions of searches, arrests, and convictions of Americans. Chief Justice Roberts recognized that danger with cell-site information and concluded that a warrant should be required for location data. But the challenges ahead will be still more complex. The mere collection of data will implicate constitutional freedoms.

Justice O’Connor once wrote, “With the benefits of more efficient law enforcement mechanisms comes the burden of corresponding constitutional responsibilities.”[82] Or as Chief Justice Roberts recently remarked at a graduation speech for his daughter’s high school, “What is very interesting can become very creepy, very fast.”[83]

[*] Marc Rotenberg is co-author with Professor Anita L. Allen of Privacy Law and Society (West 2015) and an adjunct professor at Georgetown Law where he has taught the law of information privacy since 1990. Rotenberg is also President of the Electronic Privacy Information Center in Washington, D.C. EPIC filed an amicus brief in Carpenter, joined by 33 technical experts and legal scholars. And big thanks for helpful suggestion from Natasha Babazadeh, Alan Butler, Jenifer Daskall, and Laura K. Donohue.

[1] A popular CBS series that documented the dangers of location tracking in a world without constitutional constraints. In the final season, an evil AI “Samaritan” threatens to defeat a benevolent AI “The Machine.” The heroes must escape the location tracking capability of Samaritan to save humanity. Person of Interest: return 0 (CBS television broadcast June 21, 2016).

[2] Carpenter v. United States, 138 S. Ct. 2206, 2217 (2018).

[3] Id. at 2219.

[4] Id. at 2217.

[5] Id. at 2219.

[6] Id. at 2218 (referencing United States v. Jones, 565 U.S. 400 (2012)).

[7] Id. (citations omitted).

[8] Id. at 2220.

[9] Id. at 2223.

[10] A court may issue an order “if the governmental entity offers specific and articulable facts showing that there are reasonable grounds to believe that the contents of a wire or electronic communication, or the records or other information sought, are relevant and material to an ongoing criminal investigation.” See 18 U.S.C. § 2703(d) (2018).

[11] Carpenter, 138 S. Ct. at 2211.

[12] Olmstead v. United States, 277 U.S. 438 (1928).

[13] Boyd v. United States, 116 U.S. 616 (1886).

[14] Olmstead, 277 U.S. at 438.

[15] Say what you will about enforcing the law, but Olmstead was a well-regarded citizen who imported safe liquor from Canada to the Pacific Northwest at a time when prohibition, and homemade moonshine, created a national health crisis in the United States. Not only a community leader, Olmstead also respected the hard work of law enforcement agents. He reportedly left bottles of his product for the federal agents who monitored his operations. See generally Philip Metcalfe, Whispering Wires: The Tragic Tale of an American Bootlegger (2007).

[16] Olmstead, 277 U.S. at 466.

[17] Id. at 470.

[18] Id. at 487 (Butler, J., dissenting).

[19] Id. at 474 (Brandeis, J., dissenting).

[20] Id. at 472 (quoting McCulloch v. Maryland, 17 U.S. (4 Wheat.) 316, 407 (1819)).

[21] Id. at 473 (quoting Weems v. United States, 217 U.S. 349, 373 (1910)).

[22] Id. at 474-75.

[23] Ex parte Jackson, 96 U.S. 727 (1877).

[24] Olmstead, 277 U.S. at 476 (Brandeis, J., dissenting).

[25] Id. at 479.

[26] Id. at 465–66.

[27] Communications Act of 1934, 47 U.S.C. § 151 (1934).

[28] 47 U.S.C. § 222 (2016).

[29] Boyd v. United States, 116 U.S. 616 (1886).

[30] U.S. Const. amend. V.

[31] Berger v. New York, 388 U.S. 41 (1967).

[32] Katz v. United States, 389 U.S. 347, 361 (1967) (Harlan, J., concurring).

[33] United States v. Jones, 565 U.S. 400 (2012).

[34] Id. at 411 (emphasis in original).

[35] Id.

[36] Id. at 419 (Alito, J., concurring).

[37] Id. at 414 (Sotomayor, J., concurring).

[38] Jones, 565 U.S. at 417 (Sotomayor, J., concurring).

[39] Id.

[40] Id. at 415.

[41] Id. at 418 (quoting Smith v. Maryland, 442 U.S. 735, 749 (1979) (Marshall, J., dissenting)).

[42] Riley v. California, 134 S. Ct. 2473 (2014).

[43] See, Brief of Amicus Curiae Electronic Privacy Information Center (EPIC) and Twenty-four Legal Scholars and Technical Experts in Support of Petitioner, Riley v. California, 134 S. Ct. 2473 (2014) (No. 13-132).

[44] Riley, 134 S. Ct. at 2484.

[45] Id. at 2490.

[46] Id. at 2495 (quoting Boyd, 116 U.S. at 625).

[47] Id. at 2496 (Alito, J., concurring).

[48] Id. at 2497-98.

[49] I have suggested that Justice Kagan’s concurrence in Florida v. Jardines, 569 U.S. 1 (2013), a case concerning the search of a home by a drug sniffing dog at the doorway, provided such a grand synthesis. Justice Kagan explained that the “Court treats this case under a property rubric; I write separately to note that I could just as happily have decided it by looking to Jardines’ privacy interests.” Id. at 13 (Kagan, J., concurring). In other words, it is possible to view a search as simultaneously implicating both a property interest and a Katz expectation of privacy interest.

[50] Carpenter v. United States, 138 S. Ct. 2206, 2217 (2018).

[51] Id. at 2206, 2216-17.

[52] Id. at 2218.

[53] And with predictive analytics, this data may also move time forward.

[54] Carpenter, 138 S. Ct. at 2218.

[55] Id. at 2219.

[56] Id. at 2222.

[57] Id. at 2223-35 (Kennedy, J., dissenting).

[58] Id. at 2235-46 (Thomas, J., dissenting).

[59] Id. at 2246-61 (Alito, J., dissenting).

[60] Id. at 2247 (Alito, J., dissenting).

[61] Id. at 2261 (Alito, J., dissenting).

[62] Id. (Alito, J., dissenting).

[63] Id. at 2261-72 (Gorsuch, J., dissenting).

[64] Id. at 2264.

[65] Id. at 2268-71.

[66] Id. at 2271.

[67] See 12 U.S.C. § 3401 (2018).

[68] See 18 U.S.C. §§ 2701 – 2712 (2018).

[69] Even after enactment of the comprehensive federal Wiretap Act of 1968 it was not obvious to the phone companies that they should turn over information about their customers to the government without a warrant. It took a subsequent amendment to the Act to compel compliance.

[70] Smith v. Maryland, 442 U.S. 735, 748 (1979) (Stewart, J., dissenting).

[71] Id. at 747.

[72] Kyllo v. United States, 533 U.S. 27, 34 (2001).

[73] Maryland v. King, 569 U.S. 435, 482 (2013).

[74] Carpenter v. United States, 138 S. Ct. 2206, 2251 (2018) (Alito, J., dissenting) (quoting Olmstead v. United States, 277 U.S. 438, 476 (1928)).

[75] Olmstead, 277 U.S. at 476 (Brandeis, J., dissenting).

[76] See 18 U.S.C. § 2510 (2018).

[77] See, e.g., Electronic Privacy Information Center, EPIC Urges Congress to Reform ECPA, Safeguard Locational Data (June 23, 2010), See also “ECPA Reform and the Revolution in Location Based Technologies and Services” Hearing Before the Subcomm. on the Constitution, Civil Rights, and Civil Liberties of the H. Comm. on the Judiciary, 111th Cong. (2010) (statement of the Electronic Privacy Information Center).

[78] See 18 U.S.C. § 2510 (2018).

[79] Consider for example the records of vessel location routinely recorded by the U.S. Coast Guard on behalf of the Department of Homeland Security. See Ralph Naranjo, Is AIS Chipping Away at Our Freedoms?, Practical Sailor (Feb. 2011),

[80] The discussion in Carpenter of § 222 of the Communications Act which provides some rights for consumer in the “Customer Proprietary Network Information” suggests how this might play out. Unfortunately, there was disagreement even among the dissenters of the significance of this instance of positive law.

[81] Court of Justice of the European Union, The Court of Justice Declares the Data Retention Directive to Be Invalid (Apr. 8, 2014) (“Digital Rights Ireland”),

[82] Arizona v. Evans, 514 U.S. 1, 18 (1995) (O’Connor, J., concurring).

[83] Richard Wolf, Chief Justice John Roberts to High School Graduates (and His Daughter): ‘Beware the Robots, USA Today (June 7, 2018, 4:20 PM),