what the first Civil War was fought over Slaves. Literal human resources were right up their with land as far as property value and ability to continue to earn future value. Enshrining slaves as property forever is virtually the only difference in the confederate constitution.

Lincoln was the first presidential ticket with a northern pres and vp at a time when we deliberately had an equal number of southern and northern states and a bunch of territories to be brought into the union out west. Previously it was possible for a southern pres or vp to enforce this fake equality that couldn’t last because the pres could veto and the vp could vote to break a tie. Once you break that tie you can’t put it back you can now add more northern states without issue.

What were they worried about losing as they lost ground in the house and senate again? Their property and future earnings from that property. It’s popular to quote Lincoln saying he would free none or all of the slaves if he could save the union but that doesn’t tell you what the war was about. They went to war so they could keep their slaves and We went the war so we could keep the southern states instead of having an enemy on our doorstep.