This is not quite right. You are forgetting Kentucky: a slave state that explicitly decided not to leave the union and fought alongside the non-slave states aga

This is not quite right. You are forgetting Kentucky: a slave state that explicitly decided not to leave the union and fought alongside the non-slave states against the Confederacy. Even Abraham Lincoln had declared himself as a non-abolitionist until the Gettysburg Address. He campaigned, and started his governing as a status-quo politician. The main thing that southern politicians railed against him was that he wanted to keep the compromise and have the "new territories" (areas that were not yet states) be kept non-slave territories. There is nuance here, but basically the Confederacy pissed him off so much that he changed his mind and decided that he would push for the abolition of slavery, starting by ending it by force in the Confederacy. He moderated after the war somewhat, and his death (at the hands of a Southern conspiracy to re-start the war and bring back slavery) almost got us to full equality, but wound up in a compromise that got us the Jim Crow laws.