A bit of an aside, but it seems like the South would've had a lot fewer able-bodied, young men to fight the war especially since they weren't inclined to arm black soldiers. Given that the south was primarily agrarian with fewer urban areas to draw from - the population was more sparse. How did the confederacy think they could win given that difference?
* They had more military experience and a stronger military tradition
* They were more motivated
* There were a not-insignificant number of Northerners who weren't particularly in favor of fighting a war against slavery (which, despite the "states' rights" commentators, was the real cause of the war)
* They expected recognition from the British government due to their supposed dependence of southern cotton
I just finished the book _Battle Cry of Freedom_ a couple of weeks ago. It's a fantastic and very readable single-volume history of the war and the ~20 years leading up to it, and I think every American should read it for a clear understanding of why exactly the US Civil War happened