I might agree with you in a very limited way. Certain slavery was a "Tripwire" issue. BUT, in the larger context there would have most certainly have been some other issue which would have brought about a sectional or regional War among the many factions within the United States.

It might have been between the East and the West instead of the North and South. But It would have happened in my opinion because it is human nature that power, especially political power, is not something that is easily shared.

Without a political settlement of such questions as, for example Secession, there would have always been the threat of secession by a state or groups of states.