Wrong again Jorge. That the under laying cause of the War Between the States was in fact slavery and the attendant economics of slavery in the cotton industry is argued against by only a few. It was the basic argument which drove the discussion regarding the right of the individual states to make certain determinations. It was the driving motivation for the compromises. The southern states realized that they had to maintain a balance of slave versus non-slave states in order to preserve the "peculiar institution" of slavery.
CSA soldiers fought for a myriad of reasons, peer pressure, states rights, repelling invasion, excitement, the desire to "see the elephant," economic, etc. But, the institution of slavery drove the politics that led to secession and then to war. The Northern anti-slave side controlled the pre-election discussions and debates. Strong anti-slavery newspapers disparaged the slave holding states. The threat to the economy in the south, should slavery not be allowed, insured that those in power there, almost all wealthy slaveholders, their wealth totally dependent on slavery, drove the debate in the south.
Much as today, many business people believe Americans will not perform work for low wages so they work to insure a continuing influx of people across our southern border. Little has changed over the past years. Even the chambers of commerce champion, more or less, open borders so as to insure sufficient workers for cheap labor jobs. The south learned after the war that cotton and tobacco could still be profitable, especially with the arrival of certain mechanical inventions.
While the end of slavery, not racial discrimination (we're still working on that wrinkle), was a grand result of the fighting, the greatest impact was to turn the United States in a true union of states as opposed to a confederation of states. Rightly or wrongly, America became a country with a supreme, central government. Without that result we would not be the country we are today. Whether or not one likes what the country has evolved into the "late unpleasantness" was the impetus for our strong central government and subservient state government. And, slavery and the abhorrence of slavery drove the debate, the politics, and the people to the war. "States rights' was a consideration only in so far as the wealthy land owners in the southern states wanted slavery to continue, while the majority in the north did not.
The Federal government, at the point of a gun, established that the individual states had no such power to secede. Far as I know, Texas is the only state that can leave the Union. That right was agreed to by the governments of both countries when it was agreed to admit Texas as a state. If, in fact the right of secession did exist, that right was lost due to the inability of the Confederacy to defend that right.
I suppose if you want to get to one single cause for the war, it would be . . . economics. The southern land owners wanted to preserve their life style, which certain people found against the laws of God. That's an oversimplification of course, but it's very true.