Author ORCID Identifier

Tonja Jacobi 0000-0002-5200-5765

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Third-party doctrine, Expectation of privacy, Electronic surveillance, Fourth Amendment, False-friend doctrine


Today, information is shared almost constantly. People share their DNA to track their ancestry or for individualized health information; they instruct Alexa to purchase products or provide directions; and, now more than ever, they use videoconferencing technology in their homes. According to the third-party doctrine, the government can access all such information without a warrant or without infringing on Fourth Amendment privacy protections. This exposure of vast amounts of highly personal data to government intrusion is permissible because the Supreme Court has interpreted the third-party doctrine as a per se rule. However, that interpretation rests on an improper understanding of the reasonable expectation of privacy standard developed in Katz v. United States.

There is a solution. A close reading of Katz’s logic can reorient third-party analysis from a per se rule to a tailored test of the knowledge of the sharer and the nature of the recipient, asking whether the sharer (1) knowingly exposed information (2) to the public. This interpretation allows the Fourth Amendment to better evolve with changing technology, such that the exception no longer risks swallowing the rule.

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Publication Title

Notre Dame Law Review


© 2022 Tonja Jacobi & Dustin Stonecipher.

Individuals and nonprofit institutions may reproduce and distribute copies of this Article in any format at or below cost, for educational purposes, so long as each copy identifies the authors, provides a citation to the Notre Dame Law Review, and includes this provision in the copyright notice.