> So why did the North go to war?
Because the South attacked the Federal troops on the Federal base at Ft. Sumter. When attacked, you either fight back, you ignore it or you roll over. Americans aren't the French, so rolling over wasn't an option. Ignoring a sizable military attack by traitors also isn't much of an option, unlike, say, a Cuban soldier taking a random pot-shot into Gitmo might be ignorable.
Had the Southerners not started their war of aggression, then the FedGuv would have had little cause to war against them... as the fact that secession had been a reality for quite some time and there had been no military attacks by the North proves. The CSA would have secceded, most likely failed as a nation, and then we'd have moved on from there in some way. Reconciling the democratic republicanism of the North with the feudal society of the South in a peaceful alternate history would have been interesting...
Good answer. Doesn't it seem strange that the only reason the South went to war was over slavery and that she went to war against a foe that was not fighting to end slavery?
Because the South attacked the Federal troops on the Federal base at Ft. Sumter.
No, because Lincoln and the Northern business interests he repped for (remember, Lincoln was a railroad lawyer, not an abolition lawyer or a civil-rights lawyer) were determined to drag the Southern States back into the Union by force.
The Northern economic-development model required a payor (street synonym: chump). The South was the payor. They couldn't leave. If they did, the Northerners would have to pay for their own development, which was a nonstarter for them.
There were no "traitors" before Ft. Sumter, so I'll trouble you to take down that word.
The entire State of South Carolina had renounced their citizenship and changed their allegiance openly to the Confederacy, by a lawful and moral procedure of popular convention. The People own the Constitution, not the other way around. They can leave the Union if they wish.
You are in the unenviable position of explaining how a People who are NOT free to abolish their Union and change their Constitution, are still "free" somehow.