Carter graduated from the United States Naval Academy in 1946, served on submarines and was selected to serve in the nuclear submarine program.Presidents who served.
Dems
Rosevelt - nope
Truman - yes
Kennedy - yes
Johnson - yes
Carter - nope
Clinton - nope
Republicans
Reagan - nope
Bush I - yes
Bush II - nope
Reagan was commissioned as a reserve cavalry officer in in 1935. After the attack on Pearl Harbor, he was assigned to the First Motion Picture Unit in the United States Army Air Force where he made training and education films.
Bush 43 was in the Texas Air National Guard between 1968 and 1973 (although he was AWOL during some of that period).