re: #356 Belafon
Actually, it was Truman: todayinclh.com
So, if want an exact date for when the Democratic party started to split, it was June 29, 1947.
Part of the reason why HappyWarrior was my username was his (Hubert Humphrey) 1948 DNC speech where he urged the Dems to leave the darkness of states rights and enter the sunshine of human rights. It caused Thurmond and the other Dixiecrats to leave. Funnily enough Joe Biden served in the Senate with both men.