We remember the 54th anniversary of President Kennedy's assassination this week. There is something about President Kennedy's legacy, as Alan Brinkley wrote a few years ago: President Kennedy spent less than three years in the White House. His first year was a disaster, as he himself acknowledged. The Bay of Pigs invasion of Communist Cuba was only the first in a series of failed efforts to undo Fidel Castro’s regime. His 1961 summit meeting in Vienna with the Soviet leader Nikita Khrushchev was a humiliating experience. Most of his legislative proposals died on Capitol Hill. Yet he was also responsible...