After McCarthy and Kennedy began campaigning for the nomination, President Johnson announced that he would not be running for reelection. He was too preoccupied with peace talks in North Vietnam to campaign, and although he did not announce it at the time, was concerned for his health. In fact, Johnson died just two days after the end of what would have been his second term. McCarthy and Kennedy, the two frontrunners from the Democratic Party, competed in several primaries across the country, with Kennedy coming out ahead. Soon after Kennedy gave his victory speech after his victory in the California primary, he was shot by Sirhan Sirhan. Sirhan was a Palestinian-born Jordanian who believed Kennedy betrayed Palestine by supporting Israel a year prior. Kennedy died in the hospital the following day, just over three months after the assassination of civil rights leader Martin Luther King, Jr. With Johnson and Kennedy out of the competition, Vice President Hubert Humphrey entered the race, just before the Democratic National Convention. Humphrey, who was closely associated with Johnson's war policies, created some controversy at the convention. Antiwar protestors arrived to demonstrate against Humphrey and the war, and many were beaten by the Chicago police. Still, Kennedy's supporters were unable to unify behind a candidate in time to defeat Humphrey, and he came out of the convention with the party nomination.
The Republican nomination was between former Vice President Richard Nixon and Michigan Governor George Romney. Nixon won the nomination easily, choosing Spiro Agnew of Maryland to help him appeal to southern conservatives.
Governor George Wallace of Alabama became a candidate for the American Independent Party, which represented extreme social conservatism and the South, and supported segregation in schools.
Just before the election, President Johnson ended air attacks on North Vietnam, helping Humphrey's campaign and allowing him to gain some additional support. Election Day saw an incredibly close election in the popular vote, resulting in Nixon winning with 31.8 percent of the popular vote to Humphrey's 31.3 percent. Third party candidate, Wallace, received 13.5 percent, winning only states in the Deep South. While the popular vote was extremely close, the electoral votes showed Nixon as the clear winner with 301 votes to 191 for Humphrey. Nixon won the election and became the thirty-seventh President of the United States.