Johnson had been stalled by the anti-Vietnam War candidacy of Senator Eugene Mc Carthy of Minnesota, who along with Senator Robert F.
Kennedy of New York, became the main opponents for Humphrey.
He delayed meetings with Indiana Governor Roger Branigin to arrange a favorite son "stand in" for the campaign, and neglected to hire the campaign's 1964 campaign manager Larry O'Brien, despite Humphrey's insistence.
But Humphrey was able to convince Johnson to speak to the influential National Farmers Union in Minneapolis, ahead of the Wisconsin Primary.
Humphrey experienced a surge in the polls in the days prior to the election, largely due to incremental progress in the peace process in Vietnam and a break with the Johnson war policy, but was defeated by Nixon on Election Day.
Hubert Humphrey was first elected to public office in 1945 as Mayor of Minneapolis.
As Vice President, Humphrey oversaw turbulent times in America, including race riots and growing frustration and anger over the large number of casualties in the Vietnam War.
President Johnson's popularity had plummeted as the election grew closer.
The main cause of the division was the Vietnam War, which intensified during Humphrey's tenure as Vice President and grew increasingly unpopular.
He served two, two-year terms, and gained a reputation as an anti-Communist and ardent supporter of the Civil Rights Movement.
He gave a rousing speech at the 1948 Democratic National Convention arguing for the adoption of a pro-Civil Rights plank, exclaiming "The time has arrived in America for the Democratic Party to get out of the shadow of states' rights and to walk forthrightly into the bright sunshine of human rights." That same year, he was elected to the United States Senate, where he worked closely with Senate Majority Leader Lyndon Johnson.
His aides Max Kampelman and Bill Connell began to set up an organization and held meetings with Humphrey and his advisors, encouraging him to start a campaign.
Humphrey set up offices for preparation, and unsuccessfully courted Larry O'Brien as campaign manager.