Chatrie and the Supreme Court's Embrace of Privacy Doctrine

I've been blogging here (and here) recently about Chatrie v. United States, the Supreme Court's landmark Fourth Amendment case decided late last month. Chatrie held that geofence searches, which use cellphone data to track cellphone users in a certain area at a certain time, are Fourth Amendment searches requiring probable cause and a warrant. In today’s post, I'll talk about which theories of Fourth Amendment law the Court adopted in Chatrie and which it didn't. First, I’ll explore why Justice Gorsuch hasn’t gained any support over the past eight years for his property-centered approach to Fourth Amendment searches. Second, I’ll look at the bigger picture of the Court’s embrace of privacy and rejection of traditional measures in applying the Fourth Amendment to the modern world. 

What Happened to the New Property Era in Fourth Amendment Law?

Justice Gorsuch wrote separately in Chatrie, concurring in the result. He argued that the Court should discard the Katz test, i.e. the “reasonable expectation of privacy” test, and instead resolve the case on the basis that Chatrie had a property right in his Google Location history. I discussed the profound ambiguity of the property question in one of my previous posts, and indeed there is little in existing law to suggest that an internet user would have a property right in data compiled by Google, stored on Google’s servers, and likely used exclusively by Google.

But perhaps the most remarkable thing about Justice Gorsuch’s concurrence is that, just as in Carpenter, he is writing it alone. Since 2018, when Gorsuch suggested a property-based approach to Fourth Amendment law, the membership of the Court has changed substantially, with Justices Barrett and Kavanaugh replacing Justices Ginsburg and Kennedy. Gorsuch’s approach is (at least nominally) grounded in textualist and traditional understandings of the Amendment rather than evolving notions of privacy, and thus was well suited to appeal to the new Court. A host of legal scholars and other legal actors have proposed property-centered and positive-law-centered approaches to Fourth Amendment law in recent years. The lead argument in Chatrie’s merits brief was that Chatrie had an affirmative property right in his Google Location History. Adam Unikowsky, who argued Chatrie’s case before the Supreme Court, focused almost exclusively on this position during oral arguments. Chatrie was almost a perfect case for the property argument, because Location History is especially accessible to users compared to other forms of digital metadata, and Google went out of its way to characterize this data as belonging to the user, who could access and delete it as they chose.

But Justice Gorsuch picked up exactly zero votes for his approach. Meanwhile, the privacy-based framework of Carpenter has gained Justice Kavanaugh’s vote—indeed he voted for the expanded version set out in Chatrie—as well as Justice Barrett’s vote, as she noted in a short dissent. Barrett believed that Chatrie had voluntarily exposed his movements to Google, but she “ha[s] no quarrel with Carpenter v. United States.” 

There may be several reasons why the property approach has failed to catch on, but the primary reasons are likely that it would make Fourth Amendment law even less clear than it has been under the Katz test and would underprotect digital data if applied rigorously. Grounding modern Fourth Amendment law in actual property rights works poorly because property law is complex and uncertain, with numerous forms of ownership that are divisible and combinable across people and time. The property law of digital data is even less certain, and related forms of positive law like privacy torts are far less developed than Fourth Amendment law, with its decades’ worth of precedents at all levels of the judiciary. Property rights are also malleable, and governments can manipulate them in order to facilitate pervasive surveillance. Property just doesn’t work as the basis for a wholly different body of law, and making it the center of Fourth Amendment rights would create a tangled doctrinal mess.

Justice Gorsuch’s concurrences in Chatrie and Carpenter suggest that courts should apply property law capaciously, extending it beyond its current bounds to cover things like Location History stored on Google’s servers and even cell site data compiled by cell service providers from which cell phone users are wholly excluded. But a more rigorous application of property law would likely underprotect digital data, the target of much of modern surveillance. Sensitive forms of modern information like web surfing data, communications metadata, medical and biometric data, and more are unlikely to be protected by a property-based Fourth Amendment approach. 

There are other problems with Justice Gorsuch’s supposedly textual and historical approach, which is only partially faithful to the original text and fails to reflect the Founders’ well-documented concern with privacy as well as property rights. But the problems of administrability and limited applicability to modern contexts are likely fatal for Gorsuch’s attempted reimagining of Fourth Amendment law in any event. The push by Gorsuch to make the Fourth Amendment turn on property concepts seemed like the next big thing. After Chatrie, it seems more like a lone Justice’s misguided theory. 

The Triumph of Privacy in Modern Fourth Amendment Law

At a higher level of abstraction, Chatrie also indicates that the Court is pursuing a privacy-centered Fourth Amendment jurisprudence, one that is flexible enough to preserve digital privacy in the modern era. Future cases will present different problems, and the Court may not always approach them with the sophistication and depth of Chatrie. But at least in general, the Court will not anchor the Fourth Amendment to the fading past of the pre-digital era, or address novel contexts on the basis of distant analogies to familiar ones.

More traditional approaches to Fourth Amendment law are falling to the wayside as surveillance technologies and practices continue to advance. This transformation of Fourth Amendment law and theory is necessary if the Fourth Amendment is to continue to provide meaningful protections against government intrusions in the modern era. To its enormous credit, the Court has shown itself willing to change Fourth Amendment law accordingly, at least in the limited contexts it has addressed over the past decade or so. 

In doing so, it has preserved the original spirit and function of the Fourth Amendment while updating it for a new world. And it has rejected more traditional approaches that would otherwise provide fewer and fewer meaningful constraints on intrusive government surveillance over time. Justice Alito’s dissent gives a eulogy of sorts for the old approach. He contends that Chatrie would have come out differently under historical Fourth Amendment precedents or “traditional search-and-seizure principles.” He laments that, “until Carpenter, this Court held that the Fourth Amendment protected a person’s security in only his own papers and effects, not those of a third party.” He grudgingly accepts Katz’s expansion of the Fourth Amendment to cover wiretaps and bugs, but only because of what he alleges was a cautious implementation and limited impact. 

The Chatrie majority rejects all of these points. It embraces a robust application of Katz and leans heavily on Carpenter. Its guiding star is Justice Brandeis’s famous dissent in Olmstead v. United States, a 1928 case that applied the traditional principles of the Fourth Amendment to reach a disastrous holding that ushered in the J. Edgar Hoover era of widespread surveillance abuse. As the Chatrie court writes, the Framers of the Fourth Amendment could not have anticipated the telephone or the wiretap, but they did understand the “transcendent importance” of privacy against government surveillance. In its adoption of this idea, and even more so in the holdings of the opinion itself, Chatrie embraces privacy as the core principle of Fourth Amendment protection, unfettered by the specific rules of prior technologies. 

In the scholarship of the Fourth Amendment, an influential approach counsels proceeding by analogy to physical world contexts when applying the Fourth Amendment to digital data. Most fully explicated by Orin Kerr in his recent book The Digital Fourth Amendment, this approach would depart from non-digital paradigms only when new developments “dramatically” expand or curtail government power. Kerr attempts to translate between online data and physical space, drawing analogies between forms of digital information and their superficially similar albeit functionally different real-world predecessors. Following this analogical approach, he concludes that the contents of online communications should generally be protected while non-content data like location information or to/from message metadata should generally be unprotected. Kerr specifically addresses geofence surveillance in his book, arguing that it should not be protected to any degree by the Fourth Amendment because cellphone users voluntarily disclose their data to Google. 

The Supreme Court rejected this specific argument in Chatrie, and it has also departed from the broader approach. This is the second case in a row where the Court has extended Fourth Amendment protection to non-content metadata generated by a cellphone or app. Rather than adopting the rules of pre-internet surveillance, or cautiously expanding existing law, the Court has departed from existing paradigms in order to firmly protect privacy against new forms of surveillance. It has focused directly on privacy and the appropriate balance between it and law enforcement interests, and less on adjusting old laws while hewing closely to them. 

This is all the more remarkable given the general conservatism and affinity for tradition of the current Court. But there is a reason for it. The traditionalist paradigm struggles to effectively address the complex questions posed by modern technology, and the Supreme Court has increasingly left it behind. A more modern conception of privacy, developed in cases like Carpenter and a substantial scholarly literature, has, instead, carried the day.

--Matthew Tokson