Lincoln was wrong when he said secession was not legal. It was indeed legal and cannot be proven otherwise. After the war, the US wanted to go to court with their best lawyers to prove secession was illegal. They gave up.

Less than 5% of Southerners owned slaves. And slave owners where not the ones doing the fighting. The South fought because their land was invaded by an Army.

If the North really thought that the war was about freeing the slaves, why didnt they start in their own backyard.