Elizabeth Joh

Elizabeth E. Joh is an American legal scholar and the Martin Luther King Jr. Professor of Law at the University of California, Davis School of Law. She is a leading expert on policing, surveillance technology, and constitutional law. Joh is the co-host of the podcast What Trump Can Teach Us About Con Law (informally Trump Con Law), co-created with podcaster Roman Mars, a series noted by media critics for its "civic mediation" in translating complex legal theory into public discourse.

Elizabeth E. Joh
Occupations	Legal scholar, professor
Employer	University of California, Davis School of Law
Awards	UC Davis School of Law Distinguished Teaching Award (2017)
Academic background
Alma mater	Yale University (BA) New York University (JD, PhD)
Academic work
Discipline	Constitutional law, Criminal law, Policing, Surveillance
Notable works	What Trump Can Teach Us About Con Law (podcast)

Education and career

Joh earned her Bachelor of Arts from Yale University and both her Juris Doctor and PhD in Law and Society from New York University. Following law school, she served as a law clerk for Judge Stephen Reinhardt of the United States Court of Appeals for the Ninth Circuit.

She joined the faculty at the UC Davis School of Law in 2003. She is an elected member of the American Law Institute and was appointed to the University of California Presidential Working Group on Artificial Intelligence in 2020.

Research and scholarship

Joh's research focuses on the intersection of technology and the Fourth Amendment, with particular emphasis on "high-tech policing" and surveillance discretion. Her scholarship has been widely cited for identifying how automated tools change the environment of policing and judicial oversight.

Genetic surveillance and "abandoned DNA"

Joh is a prominent critic of "genetic surveillance" and the use of genealogy databases by law enforcement. Long before the 2018 arrest of the Golden State Killer, Joh argued that the legal doctrine of "abandoned DNA"—genetic material left on items like coffee cups or trash—created a privacy loophole that the Fourth Amendment failed to address. She presented this thesis at Stanford Law School in 2008, warning that without regulation, the government could inevitably mine public trash to build a universal genetic database.

Following the rise of forensic genealogy, her legal analysis was featured in national media. She argued that the use of sites like GEDmatch by police effectively opted the entire population into genetic surveillance without their direct consent, a concept she termed "shared genetic privacy."

Robotic policing and AI

Joh has written extensively on the legal and ethical implications of "robotic policing." In her analysis of the San Francisco Police Department's 2022 proposal to deploy robots with lethal force capabilities, she argued that current laws treat robots as "neither people nor property," leaving a regulatory vacuum regarding their use of force. Her scholarship predicts that "fallible human judgment" will increasingly be delegated to machines, a shift she argues requires new "use of force" protocols specifically for AI. This work has been cited by regulatory bodies and the Los Angeles Times during debates over the deployment of the "Digidog" robot by the LAPD.

Consumer surveillance and the "Gig Economy"

Joh has identified a phenomenon she calls the "Gig Surveillance Economy," where consumer devices like Ring doorbells and apps like Citizen conscript private citizens into the state's surveillance apparatus. She argues that these technologies create "networked engines of suspicion" that bypass traditional police oversight by relying on private contracts and user agreements rather than public law. In 2018, media analysis highlighted her related argument that police access to data from "smart" cars and home devices often bypasses traditional warrant requirements.

Key publications

Her primary academic contributions in major law reviews include:

• California Law Review: Her 2007 article explored "discretionless policing," examining how automated surveillance technologies could fundamentally shift the traditional exercise of police discretion.
• Stanford Law Review: In 2009, Joh published a frequently-cited analysis of undercover policing and the legal rules governing authorized criminal activity by agents.
• Harvard Law Review Forum: Joh analyzed the "new deceptive capabilities" of police in a 2015 essay, focusing on how digital technology has enhanced the use of baits and ruses in criminal investigations.

Podcasting and public engagement

In June 2017, Joh began co-hosting the podcast What Trump Can Teach Us About Con Law with Roman Mars. The show uses contemporary executive actions and the "chaos" of modern headlines as a pedagogical "syllabus" to explain 200 years of constitutional jurisprudence to a lay audience.

The podcast received critical acclaim for making constitutional law accessible; The A.V. Club listed it as a top recommendation, noting Joh's ability to provide "sober, rational analysis" during a period of political turbulence.

Following a production hiatus, the show resumed in June 2025 with a new monthly format and under the title The 99% Invisible Breakdown: The Constitution, which features a chronological, "book club-style" analysis of the document's text.