Richard Nixon(R) cracked open some of the Dixie states in the 1960s. Until then it had mostly been a solid lock for Democrats.
The major racist acts by elected officials (school segregationists) in that region were perpetrated by Democrats. Truth be told, Rosa Parks was probably told to go to the back of the bus by a Democrat.
Most of the folks who had segregationist diners and other businesses were also Democrats.
Confederates were hunting down minority adults and children. And those Confederates were mostly Democrats. After the war they were KKK members.
During the 1948 baseball preseason, the Brooklyn Dodgers went on a barnstorming tour of the South. During that tour, Jackie Robinson and Roy Campanella were told to stay in the bus and eat their dinners there while the rest of the Dodger players and personnel were allowed to use the racially segregated restaurants that their Democrat proprietors did not allow blacks like Robinson and Campanella to eat in.