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Fourth Amendment Regulation of Information Processing

35 Pages Posted: 10 Jun 2014  

Babak Siavoshy

Non-Resident Fellow, Georgetown University - Center on National Security and the Law

Date Written: May 4, 2013


This Essay examines the Fourth Amendment implications of information processing by the government. It starts with an overview of the main challenge to regulating information processing under the Fourth Amendment: the conventional wisdom that the Fourth Amendment regulates the government’s initial access to physical evidence, but not the subsequent processing or analysis of that evidence. The distinction between “acquisition” and “analysis” of evidence underpins many familiar doctrines in Fourth Amendment jurisprudence, from plain view to the third party doctrine. The common thread in these doctrines is that the only privacy the Fourth Amendment protects is privacy at the point of collection. As one Fourth Amendment scholar has put it, once evidence is collected or exposed “the work of the Fourth Amendment is done,” regardless of whether further intrusions into privacy are possible. While it has some grounding in the case law, the conventional wisdom is wrong, at least as a categorical rule of Fourth Amendment jurisprudence. The Fourth Amendment reaches information processing, and for good reason.

One need look no further than the Court’s classic Fourth Amendment cases to see the error in the conventional wisdom. In cases like Kyllo v. United States, Skinner v. Railway Executive Labor Association, U.S. v. Jones, United States v. Jacobsen, and even Katz v. United States, the Court has reached information processing, albeit without a guiding theory. Taken together, these cases belie the conventional distinction between “acquisition” and “analysis” of evidence. They demonstrate that in a world of enhanced police technologies, traditional spatial and temporal doctrinal categories are no longer effective proxies for protecting Fourth Amendment interests. Recognizing this fact, the Supreme Court in these cases has been willing to depart from those traditional categories in order to reach information processing conduct.

If the conventional wisdom is flawed, what is the alternative? Building upon the trends already immanent in the Court’s Fourth Amendment jurisprudence, this Essay argues for reaching information processing where necessary to protect the practical privacy protected by the “right of the people to be secure in their persons, houses, papers, and effects” against enhanced police technologies. It proposes three guidelines for courts evaluating information processing under the Fourth Amendment. First, courts should adopt a contextual, rather than categorical, approach to Fourth Amendment analysis, to account for the way technology changes the meaning of government conduct. Considered in a vacuum, collecting a single piece of “exposed” evidence (Jones) is no harm to privacy, anymore than is standing in front of a house (Kyllo) or manipulating a discarded blood or urine sample (Skinner). It is only the added context of the government’s aggregation and analysis of that information that raises privacy — and Fourth Amendment — concerns.

Second, Courts should use the “practical privacy” of the past as a key measure of the reasonableness of privacy expectations today. As the Supreme Court and legal scholars have recognized, the ‘right to be secure’ is a pre-existing right, and one that is informed, in part, by the practical privacy from government intrusion that existed at the time the Fourth Amendment was enacted. Courts should account for technology’s ability to peel back this practical privacy, and where possible should “assur[e] preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted.” While practical privacy is only the starting point of the Fourth Amendment analysis, it is an important one in the regulation of enhanced technologies.

The third principle is one of judicial minimalism. Fourth Amendment regulation of enhanced technologies involves ever-changing facts and increased risks of error. Courts regulating information processing should therefore seek to apply flexible standards to draw narrow rules. This minimalist approach has two virtues: it reduces the risk of significant harm that can result from broad, categorical judgments about new surveillance technologies (see, e.g., Olmstead v. United States), while allowing judges the flexibility to make the nuanced distinctions required to solve the Fourth Amendment problems raised by a host of information processing conduct, from the imaging and analysis of smartphones to biometrics tracking and DNA analysis.

Keywords: Fourth Amendment, Information Processing, Use Restrictions, Surveillance, Analysis

Suggested Citation

Siavoshy, Babak, Fourth Amendment Regulation of Information Processing (May 4, 2013). Available at SSRN: or

Babak Siavoshy (Contact Author)

Non-Resident Fellow, Georgetown University - Center on National Security and the Law ( email )

600 New Jersey Avenue N.W.
Washington, DC 20001
United States

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