Colonel Franklin Brooke Nihart, USMC, worked at Marine Corps headquarters throughout the summer of 1955, outlined his ideas in longhand and the Code of Conduct was established with the issuance of Executive Order 10631 by President Dwight D. Eisenhower on 17 August 1955, after the Korean War. It has been modified twice—once in 1977 by President Jimmy Carter in Executive Order 12017, and most recently in President Ronald Reagan's Executive Order 12633 of March 1988, which amended the code to make it gender-neutral.