John Fitzgerald "Jack" Kennedy (May 29, 1917 – November 22, 1963), often referred to by his initials JFK, was the thirty-fifth President of the United States, serving from 1961 until his assassination in 1963. After Kennedy's military service as commander of the Motor Torpedo Boat PT-109 during World War II in the South Pacific, his aspirations turned political, with the encouragement and grooming of his father. Kennedy represented the state of Massachusetts in the U.S. House of Representatives from 1947 to 1953 as a Democrat, and in the U.S. Senate from 1953 until 1960. Kennedy defeated then Vice President and Republican candidate Richard Nixon in the 1960 U.S. presidential election, one of the closest in American history. He is the youngest man and the only practicing Roman Catholic to be elected president.