"@Hunter: so you think The North should have let the South go?"
I'm not sure really. I think that the south had the right to leave, if that is what you are asking. The country was still very young, and I'm not sure why the North thought they had the right to keep half a nation enslaved (for lack of a better word, and the irony that comes with it. ;-)). I think that things worked out for the best in the end, minus the dead soldiers, but I don't know how things would have played out if the North let them go. We would have had a lot less destruction, and who is to say that they wouldn't have eventually made up?
If I'm allowed to use hindsight, then I think that if America had been split into 2 (maybe even more eventually) different countries, then history changes a lot. Instead of one super power, you have 3+ (Texas has always wanted to be alone. :P) countries, and that could easily affect the outcome of both World Wars, along with other important international disputes.
So, no. I don't believe the North should have let the South go, but I think that the South had the right to leave.