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The Fourth Amendment and New Technologies: The Misapplication of Analogical Reasoning

Southern Illinois University Law Journal, Vol. 36, 2012

55 Pages Posted: 29 Feb 2012 Last revised: 18 Sep 2014

Marc Chase McAllister

Texas State University, San Marcos - College of Business Administration

Date Written: February 25, 2012


This article contains a lengthy reaction to the Supreme Court’s recent GPS tracking decision, United States v. Jones, 2012 WL 171117 (Jan. 23, 2012), along with the results of an original empirical study that impact the unresolved aspects of GPS tracking and a host of other cutting edge Fourth Amendment issues.

This article begins by uncovering a fundamental flaw in Fourth Amendment analysis. Under the Katz test, a Fourth Amendment “search” occurs only when the government conduct’s violates “a subjective expectation of privacy that society recognizes as reasonable.” The Katz test, by its very wording, hinges upon society’s actual expectations of privacy, expectations that are inherently fluid and case-specific. However, when courts analyze “search” claims, particularly in cases involving sophisticated technologies, courts often rely upon analogies to prior “search” cases. Usually, the analogized forms of surveillance are so distinct that analogies to them only confuse, rather than clarify, the analysis required by Katz. Highlighting this concern, this article argues that analogical reasoning to cases of an earlier technological era is a flawed approach for resolving Fourth Amendment claims, and that the actual privacy expectations of today’s society should instead control.

While there are multiple instances where analogical reasoning has been misapplied to resolve Katz claims, this article highlights the GPS tracking cases decided prior to Jones, and cases involving warrantless police access of certain electronic files.

In the pre-Jones GPS tracking cases, courts often relied upon analogies to investigative activities far removed from the particular form of surveillance at hand, such as trailing a car by vehicle. Yet, as the five concurring Justices in Jones recognized, an officer trailing a car turn-by-turn is fundamentally distinct from the long-term monitoring of a vehicle by GPS.

The second series of cases highlighted in this article derives from the Supreme Court’s 1979 decision, Smith v. Maryland, 442 U.S. 735 (1979), which established that society cannot reasonably expect privacy in information voluntarily disclosed to third parties. In recent years, Smith has been extended by analogy to a range of distinct forms of communication. For example, in United States v. Forrester, 512 F.3d 500 (9th Cir. 2007), the Ninth Circuit Court of Appeals invoked Smith and reasoned that individuals cannot expect privacy in websites they visit and in e-mail addresses with which they correspond because that information has been knowingly conveyed to a third-party provider.

The analogy between phone numbers dialed from a home phone, the type of information deemed unprotected in Smith, and e-mail addresses, an arguably similar type of “addressing information,” is plausible on its face. However, the analogy is flawed if it does not comport with the actual expectations of today’s society, ones that are undoubtedly shaped by factors non-existent in the pre-digital era.

In her concurrence in Jones, Justice Sotomayor highlighted this potential flaw, worrying that “[t]his approach is ill suited to the digital age” and stating 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.” To test Justice Sotomayor’s hypothesis, and to help inform future cases involving GPS tracking in the absence of a physical trespass, an issue left unresolved in Jones and potentially dependent upon Smith’s assumption of risk rationale, I designed and administered an original empirical study which seeks to uncover the actual views of society on these issues.

The results of my survey, which are set forth in Part IV of this article, are striking. First, my survey results indicate that most respondents would not permit GPS tracking in the absence of a warrant, particularly with respect to the type of suspect at issue in Jones. These results validate the unanimous Jones ruling, and empirically demonstrate that the Government’s analogy to visual observation of a vehicle in public, as argued in Jones, does not adequately resolve the issue. Second, my survey results refute Smith’s distinction between content and addressing information. Regardless of the form of communication at issue, respondents believed both content and addressing information should be protected by the Fourth Amendment. Finally, and most significantly, my survey results refute the assumption of risk rationale underlying Smith. Contrary to Smith, society does not believe that a person relinquishes any expectation of privacy in information voluntarily conveyed to third parties. This empirical evidence strongly supports Justice Sotomayor’s hypothesis, and impacts likely future cases of GPS monitoring in which the Government obtains GPS information directly from a third-party, such as a cell phone provider, an issue left unresolved in Jones. These results further highlight the dangers of simplistic analogies in Fourth Amendment analysis.

Keywords: Jones, GPS tracking, Fourth Amendment, assumption of risk, Smith, Forrester

Suggested Citation

McAllister, Marc Chase, The Fourth Amendment and New Technologies: The Misapplication of Analogical Reasoning (February 25, 2012). Southern Illinois University Law Journal, Vol. 36, 2012. Available at SSRN: or

Marc Chase McAllister (Contact Author)

Texas State University, San Marcos - College of Business Administration ( email )

San Marcos, TX 78666
United States

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