1. It was Because of the extreme clouding of everyone's view points.
1.1. The election of 1860
1.1.1. Not a reason, just an example
1.1.2. The North and South were very seperated not only in belief and opinion, but also just geography, economy, and like always, slavery.
1.1.3. This would cause each side to be unable to see or truly understand the other's idea. Without understanding or acceptance a conclusion can never be peacefully sought out.
1.2. The Fugitive Slave Acts
1.2.1. Both a reason and example
1.2.2. Even with federal law backing their side, the South didn't manage to get the North to follow the law. The North didn't follow the laws because it went against their beliefs.
1.2.3. This would most likely be why they wanted stronger state government, because the federal couldn't enforce.
1.2.4. Also the fact that, when the Slave Acts were started, the North didn't even honor the laws meant that the North most likely wouldn't agree to it unless it is not in the South's favor what so ever.
1.3. The multiple homocides By Nat Turner, John Brown, and more.
1.3.1. Not an example, just a reason
1.3.2. These multiple homocides showed that there were already fascists willing to kill for their beliefs before the war even started!
1.3.3. This would obviously spark tensions early on and because of so many other things as well, to release the tensions an explosion needed to happen.