If we want to look for reasons behind the Civil War, we should probably go back to the time of colonization and to the American Revolution again. There had been no singular scheme for establishing a colony on the American continent; each one had its own very distinct properties, depending on the founders and the founding principles, depending on the climatic situation, depending on the parameters set for immigration, land acquisition, business, general liberties etc.
The division between North and South separated slave states from non-slave states, more or less. The states of Missouri, Kentucky, West Virginia, Maryland and Delaware did have slaves also - but under Union pressure they did not secede, also did some Northern states have had slaves in the past, too, and racism surely was not just a problem of the South - this can also be seen from the Abolitionist plan to deport the freed slaves back to Africa, to Liberia, a plan also illustrated in Uncle Tom's Cabin, and a plan which was also turned into practice. Abolitionists didn't necessarily believe in the equality of the races; also was the Emancipation Proclamation not declared until 1863 - which makes it seem rather like an instrument of propaganda and warfare than of a true fight for freedom and equality.
Maybe the secession took place between an America divided into those hiding their racism behind indifference or abolitionist propaganda, and others who made use of it in the peculiar institution. But it is not mind-sets which directly enslave others, they may lie beneath, but to take action or not is still the much more eminent, and much more harmful way. And the hard fact remains, that - while racism may have been universal, and slavery was also supported by the constitution - it has been the South to actually engage in the ongoing enslavement of others.
Slavery was the prevaling issue of the dissension between the two parts, but the military conflict, the Civil War, was about preserving the Union.
The differences caused by the partition into slave-holding and non-enslaving states could be seen as a manifestation of a Chimera-like state created in the American Revolution, of two opposing parts fused together. Yet this is not the case, at least not in such a drastic way. North and South had more in common than what made them different, and also, there is neither "the North" nor "the South". Each state is different, so the only thing you could say is that probably Maine has more in common with Vermont, and Alabama more in common with Mississippi. Differences are mostly gradual, not abrupt, and the opposing pair created through secession was perhaps quite artificial also.
Perhaps the system is chaotic indeed, and it only needed so much friction as to incite sufficient change for both the Secession and the ensuing war to take place. If that drastically abstract level were to be upheld, this would imply that the yearning for stability is nothing more than a myth, and that the future may not be as predictable as it could seem today.