The Democratic Party was 2 parties from the day Jefferson founded it, a New York/New Jersey/Philadelphia Gentry Party and the South. By the 1920s it was three parties, the old gentry, the immigrants ie Jews and the South. The thing was no side could win without each other so for the sake of winning each side gave ground to each other. The New York wing wanted an income tax, so did the Southern wing, the New York wing wanted The New Deal, WW1 and WW2 so did the Southern wing, Oftentimes the Southern Democratic wing was sometimes as politically liberal as the New York wing on some issues EXCEPT FOR SEGREGATION which was a conservative issue. The Northern Democrats ignored the South's politics and the Southern Democrats ignored the slow march toward Communism.
The Northern Democrats Aristocratic wing died out and was replaced completely by the Social Justice Urban and Jewish Element around the time of WWII. After the war, the New Democratic Party attacked their Southern wing on the orders of Moscow and Jewry driving the Southern Democrats either into slow extinction via death or into the Republican Party. Certain ones like Fritz Hollings Robert Byrd Richard Russell and William Fullbright remained Democrats until death, others like Strom Thurmond became Republicans.
Today the Democratic Party is the Communist Party. The Republican Party is merely the Moron Party.