During the 1960s, the Democratic Party began to lose support because of its civil rights policies, its conduct of the Vietnam War, and the growing costs associated with both.

In 1963, President Kennedy proposed legislation barring discrimination in public accommodations. In July 1964, a few months before the presidential election, President Johnson signed the Civil Rights Act into law, after which he said to his aide, ”I think we just delivered the South to the Republican Party for a long time to come.” In 1965, Johnson signed the Voting Rights Act. Civil rights became a political issue clearly associated with the Democratic Party.

The Vietnam War also caused divisions within the Democratic Party. During the 1964 presidential campaign, President Johnson pledged, "We are not about to send American boys nine or ten thousand miles away from home to do what Asian boys ought to be doing for themselves." Johnson, however, implemented a draft system in 1965 and dramatically escalated U.S. involvement in Vietnam. The American people strongly preferred a negotiated settlement or treaty rather than a major U.S. military commitment. Antiwar activists began to demonstrate publicly against the United States’ involvement in the conflict. Eugene McCarthy, a Democrat, announced his intention to run against Johnson in the 1968 election on an anti–Vietnam War platform, reflecting the widening rift within the Democratic party.