The assassination of President John F. Kennedy in 1963 brought to the forefront many long-standing questions about presidential succession. When the president died, did the vice president automatically become president, or only serve as acting president? What happened when the vice presidency was vacant? Who determined when the president was disabled and incapable of carrying out official duties? The Twenty-fifth Amendment, passed by Congress in 1965 and ratified in 1967, at long last answered these questions.