Cass Robert Sunstein (born September 21, 1954) is an American legal scholar, particularly in the fields of constitutional law, administrative law, environmental law, and law and behavioral economics, who was the Administrator of the White House Office of Information and Regulatory Affairs in the Obama administration. For 27 years, Sunstein taught at the University of Chicago Law School. Sunstein is the Robert Walmsley University Professor and Felix Frankfurter Professor of Law at Harvard Law School.