The Democrats that fought a civil war to defend slavery and afterwards started the Ku Klux Klan❓ 😂 You are free to believe as you wish.
The war was not about slavery. Just ask Mr Lincoln. He said so.
Both sides of the Civil War had serious problems.
The South wanted real freedom for themselves even as they practiced slavery for others.
The North and especially the Republican party were full of actual communists who had fled failed revolutions in Europe and sought to establish the tyrannical federal empire that became what we have today.
The soldiers of the south fought for states rights. It was the north that decided the specific issue. As far as slavery the south decision was to phase it out. Which the confederate constitution set a law to not import any new slaves.