American Enterprise Institute JOHN YOO is one of America's best-known conservative constitutional scholars. He is currently the Emanuel S. Heller Professor of Law at the University of California, Berkeley, a visiting fellow at the Hoover Institution, Stanford University, and a visiting scholar at the American Enterprise Institute. Previously, he served as an official in the U.S. Justice Department during the George W. Bush administration, general counsel of the U.S. Senate Judiciary Committee, and as a law clerk to U.S. Supreme Court Justice Clarence Thomas. He has written several books on American foreign policy and the power of the executive branch--including