Why do some people call it the War of Northern Aggression and why do most people believe the war was only over slavery. I realize that was a large part but it also had to do with federalism and the balance of power between the federal and state governments, did it not?
While there's always more to be said, it's worth checking out our FAQ, which features two good answers in particular from u/Georgy_K_Zhukov about the causes of the Civil War and how slavery not only played the largest part, but was at the root of many of the other causes as well (e.g. conflicts over "states' rights" were really conflicts over states' rights... to allow/ban/regulate slavery).