Which of these U.S. Presidents served in the military?

Richard Milhous Nixon (January 9, 1913 – April 22, 1994) was the 37th president of the United States, serving from 1969 until 1974. His five years in the White House saw the conclusion of the U.S. involvement in the Vietnam War, and the establishment of the Environmental Protection Agency. Nixon's historic visit to China in 1972 eventually led to diplomatic relations between the two nations. He also presided over the Apollo 11 moon landing, which signaled the end of the moon race. In 1974, because of the Watergate scandal, he was forced to resign in the face of almost certain impeachment and removal from office—the only time an American president has done so.

During World War II, Richard Nixon applied to join the United States Navy. His application was successful, and he was appointed a lieutenant junior grade in the U.S Naval Reserve (U.S. Navy Reserve) on June 15, 1942.

In October 1942, he was assigned as aide to the commander of the Naval Air Station Ottumwa in Iowa until May 1943. He received a Navy Letter of Commendation (awarded a Navy Commendation Ribbon which was later updated to the Navy and Marine Corps Commendation Medal) from his commanding officer for "meritorious and efficient performance of duty as Officer in Charge of the South Pacific Combat Air Transport Command". On October 3, 1945, he was promoted to lieutenant commander. He retired from the U.S. Naval Reserve on June 6, 1966.