Incumbent president Lyndon B. Johnson had been the early front-runner for the Democratic Party's nomination, but withdrew from the race after narrowly winning the New Hampshire primary. Eugene McCarthy, Robert F. Kennedy, and Humphrey emerged as the three major candidates in the Democratic primaries until Kennedy was assassinated. Humphrey won the nomination, sparking numerous anti-war protests. Nixon entered the Republican primaries as the front-runner, defeating Nelson Rockefeller, Ronald Reagan, and other candidates to win his party's nomination. Alabama's Democratic governor, George Wallace ran on the American Independent Party ticket, campaigning in favor of racial segregation.