Oh come on. You all lost the war and 143 years later you're still pissed. Why do you think the North would have been any more adult about losing? A separation as a result of the war would have left two hostile countried staring at each other. And most likely would have led to future wars.
The south would have been forced to deal with an end to slavery, cause that genie was out of the box never to return.
With all due respect I think that's nonsense. Having fought a costly war to create a country where slave ownership was protected, I don't see the South rushing to get rid of it. What would they have replaced it with?
The U.S. without the south's stabilizing influence to offset the communist tendency's of the Northeast goes beyond my poor ability's to imagine.
So you see a drift towards socialism in the North, and I think the South's rush towards totalitarian fascism would have been rapid and irreversable. Not a pretty picture in either case.