General Colin Powell graduated from the Command and General Staff College in 1968.
2- Westpoint college in his twenties, and an army command college right before he became the leader of the allied armies. I don't know if it counts but he became president of some other college for a while after he retired from the military.
vice president
President
Lee was Commandant at West Point prior to the Civil War. He resigned when he was offered the command of the Union Army, from President Lincoln, but took the command of the Confederate Army.
Vice President The title of the second-in-command is deputy or vice-
Vice President The title of the second-in-command is deputy or vice-
Vice President The title of the second-in-command is deputy or vice-
the president...
All of them
The Speaker Of The House
The vice-president becomes President if the President becomes incapacitated. However, the Veep does not have any presidential powers. No one is officially second in command to the President. Sometimes various members of the White House staff make decisions for the president with or without his permission.