The Fourth Amendment In An Age Of Surveillance

Author: David Gray
Publisher: Cambridge, UK; New York: Cambridge University Press, 2017. 314p.
Reviewer: Jack E. Call | January 2018

This book is an important contribution to the growing body of literature addressing the question of how to protect society from the threat of extensive privacy invasions by the government resulting from the development of new surveillance technologies and the extensive use of stop and frisk programs. Gray’s critique of stop and frisk programs is well done, but is probably old news for some readers. On the other hand, his description of emerging technologies will greatly expand the knowledge of many readers of this book.

Most people realize that their cell phones contain a GPS program and would probably not be surprised to learn that government agencies have the capability of using these programs to track the location of its user. However, it is less well known that cell phones are in contact with cell towers within range of the phones whenever those phones are turned on, and that cell phone providers have a record of that information (called cell site location information). (The question of whether the police need a warrant to obtain a record of a particular phone’s cell site information is presently before the U.S. Supreme Court). Even more surprising is that many pieces of retail merchandise, credit cards, driver’s licenses, passports, identification cards, and other commonly carried items often contain Radio Frequency Identification (RFID) tags, which can be used to obtain the location of the item imbedded with the tag or to determine when and where the item was used.

Cell site simulators can be used to “trick” a cell phone into communicating with the simulator (rather than a cell phone tower). A user of the simulator can eavesdrop on calls made from a phone, as well as access texts on the phone and the phone’s internet usage. Drones and “Big Data” are also increasingly used by law enforcement agencies. Big Data “is an umbrella term applied to technologies and programs that aggregate, store, and analyze large amounts of information of different kinds from a variety of sources” (p. 38). The acquisition by the National Security Agency of the telephone numbers called by millions of telephones is an example of Big Data. The use of Big Data is exacerbated by the development of information-sharing environments where agencies share data from “surveillance records, flight manifests, health records, and information relating to online activities” for aggregation and analysis (p. 40).

In order to put the constitutional problems associated with this New Surveillance (my term, not Gray’s) in proper perspective, Gray provides a brief history of Supreme Court interpretation of the amendment. He concludes that the amendment is largely ineffectual in dealing with New Surveillance problems because of the Court’s decision in Katz v. U.S., where the Court decided that the key to determining whether police action is covered by the Fourth Amendment turns on whether the police intruded upon a “reasonable expectation of privacy.” The more logical and appropriate way to answer this question, Gray argues, would have been to focus on what the word “search” meant to people in the late 18th Century. That approach would call for using a practical definition of search, consistent with everyday usage: if the police are looking for something, they are searching.

The Katz approach is problematic because it led to the Court’s development of three doctrines that inhibit its ability to deal effectively with New Surveillance issues: the public observation doctrine, the third-party doctrine, and the standing doctrine. The public observation doctrine provides that the Fourth Amendment does not apply to police acquisition of information exposed to the public. It leaves many New Surveillance techniques outside Fourth Amendment review and regulation.

Under the third-party doctrine, information shared with third parties (such as banks and telephone companies) loses its Fourth Amendment protection because the person sharing the information loses a privacy interest in the information when shared with someone else. The doctrine provides an arguable constitutional justification for many of the Big Data collection programs. The standing concept permits only those persons whose privacy interests are invaded by the police to raise legal objections to the police behavior. The doctrine is problematic because people who may be affected by government surveillance have not yet been personally affected or are unable to determine if they have been personally victimized.

Gray presents five proposals for protecting persons from the dangers of the New Surveillance. A market-based approach contends that the market will develop ways of preventing government intrusions through the use of technology, such as encryption protocols. Gray argues that the market-based approach results in a technological arms race that the private sector is likely to lose.

The second proposal is the so-called mosaic theory, which focuses on how much information a particular surveillance technique acquires. Justice Alito’s concurring opinion in the GPS device case takes this approach, based on the idea that using the GPS device to track the movements of the defendant’s car for 28 days intruded upon a reasonable expectation of privacy. Gray’s concern with this approach is that it may prevent the police from engaging in many legitimate activities “including not only human surveillance, witness interviews, and the analysis of physical evidence but also public records searches, the use of confidential informants, and undercover operations” (p. 113).

The third proposal, the durational approach, focuses on how long the surveillance continues. This approach is subject to many of the same criticisms as the mosaic approach. For example, this approach might place in jeopardy long-term undercover operations.

The fourth proposal is a content-based approach, which focuses on the type of information being obtained. Gray is uncomfortable with this approach because it violates a long-standing constitutional principle of content neutrality, by requiring courts to make judgments about the relative importance of different types of information.

The final proposal, favored by Gray, is a technology-centered approach that focuses on the means and methods used by the government to obtain information. The key question is whether the means and methods used by the police provide them “an unlimited license to deploy and use modern surveillance technologies” (p. 124).

Gray believes that the Supreme Court, in Riley v. California, has already moved in this direction, by requiring the police to obtain a warrant before examining the contents of a cell phone seized during a search incident to arrest. The Court recognized that “features of cellular phones . . . distinguish them as a technology from items and areas usually covered by the search incident to arrest rule” (p. 127). Gray uses this “means and methods” approach as the basis for his specific proposals in Chapter 6 for controlling the New Surveillance.

The next two chapters set up Gray’s proposals. Chapter 4 returns to the original understanding of the words in the Fourth Amendment to argue that the proper definition of search is “examining, seeking, or trying to find a person, exploring a house, looking through papers, or examining personal property” (p. 158). The chapter also develops an argument that the Fourth Amendment “guarantees a collective right to prospective remedies [to protect] against threats of unreasonable search and seizure” (p. 134).

Chapter 5 discusses Miranda v. Arizona, the Fourth Amendment warrant requirement, and the exclusionary rule as examples of remedial measures established by the Supreme Court to control the pervasive police presence that began to develop in the late 19th century. Gray introduces the concepts of effectiveness, enforceability, and parsimony as criteria for evaluating the usefulness of prospective remedies. Effectiveness and enforceability are relatively straightforward. Parsimony refers to the need to give the police only the authority necessary to carry out their responsibilities effectively, and balances that need against the equally important need to protect people’s privacy.

The first five chapters lay the foundation for Gray’s conclusion that, in determining whether the Fourth Amendment (or other legal structures) should be used to regulate searches, the question should be “whether leaving [contemporary surveillance technologies] to the unfettered discretion of law enforcement would threaten the right of the people to be secure against unreasonable searches and seizures” (p. 251). Gray applies this approach to the New Surveillance technologies and techniques discussed in previous chapters to determine if each of them is a search and, if so, how best to regulate their use by government.

Gray concludes that all the New Surveillance techniques are searches under the Fourth Amendment. In regulating the use of tracking technologies, drones and cell site simulators, Gray looks to the Wiretap Act of 1968 for guidance. That regulatory model requires (1) court orders based on probable cause that a crime has or is occurring and the action authorized by the court order will likely yield evidence relevant to that crime; (2) demonstration by the police that other less intrusive means of obtaining the evidence are not available; (3) police procedures designed to minimize the capture of unrelated, private information; and (4) a requirement that police report back regularly to the judge issuing the order on the progress of the operation. Special considerations concerning each technology require some differences in the way the Wiretap Act model would apply to each surveillance technique, but the model provides the basic approach.

Regulation of Big Data poses special challenges because the need for control varies with the operational stage at which the data is collected or utilized. Each of these eight stages – deployment, data gathering, data aggregation, data storage, data access, data analysis, accessing the results of data analysis, and uses of data analysis – calls for somewhat different control measures. The warrant model of the Wiretap Act does not work well in this setting. Common features of the measures Gray proposes are controlling who has access to the data and requiring regular audit reports to protect against abuses. The challenges for control of big data suggest a need for a comprehensive approach for which courts are not well-suited; consequently, a legislative system of control measures would be more appropriate.

Finally, Gray addresses stops and frisks. He cites statistics from New York City and Baltimore to suggest that the use of stop and frisk by the police is currently out of control. He attributes this situation to a lax approach to the reasonable suspicion standard by the courts (which allows references by the police to “furtive movements,” “inappropriate attire,” or “a suspicious bulge” to establish reasonable suspicion) and the standing rule (which makes it difficult to obtain injunctions against overly aggressive stop and frisk programs). The primary solution to this problem lies in changing the standing rule to recognize that freedom from improper stops of people is a collective right. Extending standing to any one, whether or not the person has personally been stopped or frisked, would permit groups with more resources than individual litigants to challenge excessive stop and frisk programs. It would also make injunctive relief easier to obtain and shift the focus to “the means, methods, and practices [of the police] rather than on the isolated facts of individual cases” (p. 283).

This book might have benefited from focusing solely on the 4th Amendment implications of new technologies and omitting the discussion of stops and frisks. Gray is right, of course, that pervasive stop and frisk programs are a troublesome type of surveillance. However, there is much discussion in the legal literature of the problems associated with intensive stop and frisk programs, and Gray’s proposals do not break new ground. In addition, the stop and frisk issues are qualitatively different from the new technology issues. His discussion of new technologies and the legal problems they pose represent an important contribution to the literature. That discussion could have been expanded and enhanced if the stop and frisk issues had not been included. That criticism aside, it is difficult to imagine any reader of this book who would not come away with a greater appreciation of the threat the New Surveillance poses to our privacy rights, and the difficulties our legal system has had in responding to date.


Katz v. U.S., 389 U.S. 347 (1967).
Miranda v. Arizona, 384 U.S. 436 (1966).
Riley v. California, 134 S.Ct. 2473 (2014).

Jack E. Call, Professor of Criminal Justice, Radford University

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