Last time Democrats met in Philadelphia was 1948
The young mayor from Minneapolis had only minutes to make his case to Democratic National Convention delegates gathered here in 1948. He used them to deliver a speech that steered his party away from support for government-sanctioned segregation and toward an embrace of civil rights that continues to reverberate in an American political system still grappling with race.
My friends, to those who say that we are rushing this issue of civil rights, I say to them we are 172 years too late, Hubert H. Humphrey proclaimed from the floor of Philadelphias Convention Hall, in a voice that sounds confident but ragged in a scratchy 68-year-old recording.
He went on: To those who say that this civil rights program is an infringement on states rights, I say this 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.
(snip)
The fallout was immediate: The entire Mississippi delegation walked out mid-speech, as did half the group from Alabama. But those who remained approved the civil rights plank. Truman was elected that November, and Humphrey won his first term in the U.S. Senate.
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http://www.startribune.com/humphrey-speech-on-race-reverberating-as-democrats-return-to-philadelphia/388088162/
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We know how influential he was with LBJ in signing the Civil Rights Act of 1964. Which make it even more shameful that so many liberals stayed home in 1968 that ended up in Nixon winning.