McCain at least put on the uniform. Remember Willard’s assertion that his healthy adult sons working on his campaign was equivalent to military service ? We have yet to ascertain what was the last member of his immediate family who has put on the uniform back to the 1800s.
I realize it's not like actually serving in the military, but don't sell George Romney's war contribution short:
In 1940, as World War II raged overseas, Romney helped start the Automotive Committee for Air Defense, which coordinated planning between the automobile and aircraft industries. Immediately following the December 1941 attack on Pearl Harbor that drew the U.S. into the war, Romney helped turn that committee into, and became managing director of, the Automotive Council for War Production. This organization established a cooperative arrangement in which companies could share production improvements, thus maximizing the industry's contribution to the war production effort.