Well, the Klan was founded by Confederate veterans.
The Klan was founded by democrats who not only happened to be Confederate War veterans, but also supported slavery before the war and built a political system to perpetuate it, and when they were thwarted on the filed of battle, built another political system--Jim Crow--to perpetuate their racial hatred.
In every case, it was a certain subset of people--democrats--who had their hand in all these things.