In November 1960, at the age of 43, John F. Kennedy became the youngest man ever elected president of the United States. Theodore Roosevelt had become president at 42 when President William McKinley was assassinated, but he was not elected at that age. On Nov. 22, 1963, Kennedy was shot to death in Dallas, Tex., the fourth United States president to die by an assassin's bullet. Kennedy was the nation's first Roman Catholic president. He was inaugurated in January 1961, succeeding Republican President Dwight D. Eisenhower. He defeated the Repub ....