Edit: Seriously though, while Lincoln had no intention to emancipate the slaves where slavery already existed, he did intend to restrict slavery to where it already existed. That and the nullification of the fugitive slave laws by northern states, and Lincoln's hint that he wouldn't enforce those laws, helped drive secession. And yes, tariffs were an issue, but tariffs were at historic lows when Lincoln was elected and he wouldn't have had the votes to raise tariffs but for the resignation of southern senators after their states seceded. The civil war was really a grudge match between greedy northern industrialists and greedy southern planters. The working class of both sides really didn't want a fight, that's why both sides (starting with the South) instituted a draft.