I mean, the war didn’t start because the North wanted to end slavery in the South…

It started because the federal government wouldn’t force northern states who had abolished slavery to return escaped slaves to Southern states.

The part about abolishing slavery nationwide didn’t come up until the war was going on, and that was more an economic sanction than anything else.

So it really did start because of state rights, it’s just it was the northern states fighting for that and the Southern States wanting a federal government that was willing to force states to do stuff.