John Choon Yoo (born July 10, 1967) is a Korean-American attorney, law professor, and author. He served as a political appointee, the Deputy Assistant U.S. Attorney General in the Office of Legal Counsel, Department of Justice (OLC), during the George W. Bush administration. He is best known for his opinions concerning the Geneva Conventions that legitimized the War on Terror by the United States. He also authored the so-called Torture Memos, which concerned the use of what the Central Intelligence Agency called enhanced interrogation techniques including waterboarding.