While I agree with the facts of the first answer to this question, I struggle to wholeheartedly blame the institution of slavery for bringing about the Civil War. It's impossible to argue with the facts presented in the prior answer to this question. Slavery was indeed the moral issue of the day; however, we must be careful not to oversimplify the underlying rift between North and South.
Southerners were, generally speaking of course, more politically conservative than Northerners. This is a trend that exists even today. The Bible Belt exists in the southern region of the U.S. and the Christian revivals that took place in the South prior to the Civil War indicate an overall devotion to faith and conservatism that was distinct from the North.
We must also not forget the largely rural setting of the South and the much more urban setting of the North as another factor. Southerners had to rely on themselves much more in their environment, and the threat of revolting slaves on farms/plantations always gave southern culture a flavor of violence. This, coupled with staunch adherence to Biblical conservatism, fostered an independent spirit that made the South antagonistic toward any type of large scale reform. Reducing the spread of slavery into newly organized territories just happened to be the reform that Southerners saw as contrary to the American spirit. The formation of the Republican party and the swift presidential rise of an obscure senator from Illinois was also, while not a reform to policy, a big enough change for the South to resist.
Another note to consider is that the Antebellum world was a world much larger than our own. Leading statesmen were more loyal to their own states than to the overall union. So when the tension over national politics reached fever pitch, Southerners opted for succession rather than continue to be part of a Union that they saw as optional.
In conclusion, we must not always be so quick to blame slavery wholeheartedly for bringing about the Civil War. Slavery just happened to be the fuse that ignited the powder keg of the Civil War, a Civil War decades in the making over differences in both character and culture between North and South. All of the factors that contributed to the divide between North and South should not go unnoticed if one wants a more complete view of US history.