Automation and the Fourth Amendment

67 Pages Posted: 10 Sep 2009 Last revised: 20 Mar 2024

See all articles by Matthew Tokson

Matthew Tokson

University of Utah - S.J. Quinney College of Law

Date Written: September 10, 2009


The Supreme Court has held that an individual relinquishes any Fourth Amendment interest in information that he or she voluntarily discloses to a third party. Known as the “Third Party Doctrine,” this controversial rule is increasingly problematic in an age where a large proportion of personal communications and transactions are carried out over the Internet. Internet users expose virtually all of the information they generate online - emails, web surfing histories, search terms, and more - to online entities and service providers. As such, many scholars have assumed that Internet information will be unprotected by the Fourth Amendment.

Yet the information disclosed to these online third parties is generally not exposed to human beings at all; rather, it is processed entirely by automated equipment. Neither courts nor scholars have squarely addressed whether disclosure to these automated third parties is sufficient to eliminate Fourth Amendment protection. However courts have, without discussing the issue, already begun to treat automated Internet systems as the equivalent of human beings.

This Article examines how this emerging body of law threatens to deprive personal information on the Internet of effective legal protection. It offers a novel theoretical and legal analysis of information disclosure to automated Internet systems, and concludes that individuals whose information is exposed only to automated systems incur no cognizable loss of privacy. It then examines available data about the behavior and privacy expectations of Internet users that reveals that they sharply distinguish between disclosure to humans and disclosure to automated systems, even if courts thus far have not. These relatively intuitive concepts have been widely overlooked, and they have potentially enormous implications in several areas of law and theory. This Article explores these implications, challenging existing privacy market theories and conceptions of user behavior, and proposing a new model of Fourth Amendment privacy on the Internet.

Keywords: Fourth Amendment, automation, privacy, internet, smith, technology, computer, karo, kyllo, privacy market, cloud, email, URL, IP address, third party doctrine

JEL Classification: K14

Suggested Citation

Tokson, Matthew J., Automation and the Fourth Amendment (September 10, 2009). 96 Iowa L. Rev. 581 (2011), Available at SSRN:

Matthew J. Tokson (Contact Author)

University of Utah - S.J. Quinney College of Law ( email )

383 S. University Street
Salt Lake City, UT 84112-0730
United States

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