|Caro talks about a lot of things in his C-Span interview, among them the Civil Rights bills that Johnson got passed over the years. One episode that I had completely forgotten about that actually had nothing to do with Johnson, but a lot to do with civil rights as well as split conventions (relevant today), was on Hubert Humphrey at the 1948 Democratic convention. Wiki's account of it is interesting--a little history lesson that once again demonstrates that unintended consequences are the rule in human affairs, not the exception.|
The national Democratic Party of 1948 was split between liberals, who thought the federal government should actively protect civil rights for racial minorities, and southern conservatives, who believed that states should be able to enforce racial segregation and infringe on the rights of non-white citizens.
At the 1948 Democratic National Convention, the party platform reflected this division and contained only platitudes in favor of civil rights. The incumbent president, Harry S Truman, had already issued a detailed 10-point Civil Rights Program that called for aggressive federal action on the issue of civil rights. He, however, supported the party establishment's platform that was a replication of the 1944 Democratic National Convention plank on civil rights.
A diverse coalition opposed this tepid platform, including anti-communist liberals like Humphrey, Paul Douglas and John Shelley, all of whom would later become known as leading progressives in the Democratic Party. These liberals proposed adding a "minority plank" to the party platform that would commit the Democratic Party to a more aggressive opposition to racial segregation. The minority plank called for federal legislation against lynching, an end to legalized school segregation in the South, and ending job discrimination based on skin color. Also strongly backing the liberal civil rights plank were Democratic urban bosses like Ed Flynn of the Bronx, who promised the votes of northeastern delegates to Humphrey's platform, Jacob Arvey of Chicago, and David Lawrence of Pittsburgh. Although viewed as being conservatives, these urban bosses believed that Northern Democrats could gain many black votes by supporting civil rights, and that losses among anti-civil rights Southern Democrats would be relatively small. Though many scholars have suggested that labor unions were leading figures in this coalition, no significant labor leaders attended the convention, with the exception of the heads of the Congress of Industrial Organizations Political Action Committee (CIOPAC), Jack Kroll and A.F. Whitney.
Despite aggressive pressure by Truman's aides to avoid forcing the issue on the Convention floor, Humphrey chose to speak on behalf of the minority plank. In a renowned speech,  Humphrey passionately told the Convention, "To those who say, 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! To those who say, 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 walk forthrightly into the bright sunshine of human rights!" Humphrey and his allies succeeded; the pro-civil-rights plank was narrowly adopted.
As a result of the Convention's vote, the Mississippi and one half of the Alabama delegation walked out of the hall. Many Southern Democrats were so enraged at this affront to their "way of life" that they formed the Dixiecrat party and nominated their own presidential candidate, Governor Strom Thurmond of South Carolina. The goal of the Dixiecrats was to take Southern states away from Truman and thus cause his defeat. The Southern Democrats reasoned that after such a defeat the national Democratic Party would never again aggressively pursue a pro-civil rights agenda. However, the move backfired. Although the strong civil rights plank adopted at the Convention cost Truman the support of the Dixiecrats, it gained him many votes from blacks, especially in large northern cities. As a result Truman won a stunning upset victory over his Republican opponent, Thomas E. Dewey. Truman's victory demonstrated that the Democratic Party could win presidential elections without the "Solid South", and thus weakened Southern Democrats instead of strengthening their position. Pulitzer Prize-winning historian David McCullough has written that Humphrey probably did more to get Truman elected in 1948 than anyone other than Truman himself