Cass Sunstein
American legal scholar, the Robert Walmsley University Professor at Harvard Law School and founder of its Program on Behavioral Economics and Public Policy — by wide citation counts the most-cited legal scholar alive. Co-author, with Richard Thaler, of Nudge: Improving Decisions about Health, Wealth, and Happiness (2008), the book that put choice architecture and libertarian paternalism into mainstream policy debate; author of dozens of further books spanning constitutional law, behavioural economics, and regulation, including The Cost-Benefit Revolution (2018), On Freedom (2019), Noise (2021, with Daniel Kahneman and Olivier Sibony), and On Liberalism: In Defense of Freedom (2025).
Sunstein served as Administrator of the White House Office of Information and Regulatory Affairs under President Obama (2009–2012), where he applied cost-benefit analysis and behavioural insights directly to federal rulemaking, and later worked on regulatory policy and border operations at the Department of Homeland Security under President Biden. He clerked for Justice Thurgood Marshall and taught for decades at the University of Chicago Law School before moving to Harvard in 2008.
Core positions
Sunstein’s defining intellectual move is pairing rigorous legal doctrine with an empirical, behavioural-economics account of how people actually decide — treating law and psychology as complementary tools for the same problem rather than separate disciplines. In Nudge, this yields libertarian paternalism: government and institutions can steer choices through defaults and framing (choice architecture) without removing options, on the ground that people’s actual decisions often diverge from their own considered preferences.
On free speech and the First Amendment, he holds a doctrinally conservative but behaviourally informed position: speech protections attach to persons, not to the technologies — printing presses, film, or now AI — that carry their words, and the strength of a restriction turns on whether it targets content (presumptively invalid) or is content-neutral (permissible with justification). On liberalism itself, his 2025 book argues the threat to liberal societies is predominantly external — illiberal and anti-liberal forces — rather than self-undermining, though liberalism carries no particular resources to replenish the norms of cooperation and mutual support that a flourishing society also needs.
He has proposed extending legal protection into newer territory: a right not to be manipulated (distinct from a right against falsehood), grounded in the same instinct that produced privacy law a century ago, and a cheaper libel remedy for merely negligent falsehoods that currently fall outside the New York Times v. Sullivan actual-malice standard.
In the wiki
- Cass Sunstein on Liberalism and Rights in the Age of AI — Conversations with Tyler, Ep. 262: liberalism’s durability, AI and the First Amendment, a proposed right not to be manipulated, AI-run trials
- Daniel Kahneman — co-author on Noise (2021); Sunstein invokes Kahneman’s method here on the limits of exotic-hypothetical reasoning
- Enlightenment — Sunstein’s account of why liberalism does not self-maintain extends this concept page’s open question about what maintaining liberal norms requires