He graduated from Harvard University in 1940, before joining the U.S. Naval Reserve the following year. During World War II, he commanded a series of PT boats in the Pacific theater and earned the Navy and Marine Corps Medal for his service. Vice President Lyndon B. Johnson assumed the presidency upon Kennedy's death. Marxist and former U.S. Marine Lee Harvey Oswald was arrested for the state crime, but he was shot and killed by Jack Ruby two days later. 'We can learn our jobs together', he stated.