History may teach us a lot of things, of which, not all those things are actually correct, and sometimes what is being taught is deliberately deceptive. When it comes to the Civil war which cost the lives of 620,000 men and untold millions of dollars wasted on all the killing and infrastructure destroyed, it is a crying shame, that so few, could cause the destruction and loss of life for so many.
One basic theory about the Civil war is such was fought over slavery and to thereby keep the Union together, for a house divided against its very self, cannot stand. So too, it was said, it was about State rights, that a State had the right to secede from the union, or to nullify Federal law. There are a lot of theories about the Civil war, of which, basically none of the mainstream theories of our Civil war, really gets it right.
That is to say, the most appropriate way of looking upon our Civil war, is not ever to see it as a war of State rights, for States did not then, nor did they ever, have the right to secede from the Union, for this Union of States, is permanent, and allows no exceptions or exemption to its unity. So too, while a house divided will not stand, the Northern States were amendable to slavery in the sense, that they did not believe that the Constitution as it stood, and without amendment, permitted the abolition of slavery; but once those States so seceded and created their own rival government, with its own authority, then it was the right and the sacred duty of those Northern States to put down that rebellion directed against the Union, especially in consideration of who it was that actually fomented such a rebellion.
In point of fact, the southern rebellion primarily was generated by those that were in authority in those States that pushed so strongly for disunion, and those that were most interested in rebellion, were those that had the most to risk and quite obviously the most to lose, if the present system, built around slave labor was somehow to become illegal or dissolved. In the south, the power was held solely and exclusively in the hands of the plantation elite. That is, those that own the best, most plentiful, and most productive lands also owned the greatest amount of slaves, and in an era in which agriculture was truly sweat labor, having those that labored that were considered to be property of those that owned such, was extremely lucrative and beneficial for those owners.
Because the plantation owners held the most property, as well as holding the lion's share of material assets, they made it a point to be in full control of the legislative, judicial, extrajudicial, press, and any other pertinent phase of that State's political process. So too, for the most part, this meant that free white men, did not dare bite the hand that fed them, for in the class hierarchy of the south, being white, brought a certain degree of courtesy, respect, and status, reserved for those simply born white, even if they were to a large extent, uneducated, uncouth, and exploited.
The southern white men that suited up and went to battle to defend the "honor" of the south were hoodwinked into doing so, for they did the fighting and they did the dying. The defeat of the south was the one-time opportunity to put a sword to those great plantation estates, the landed elite, and to bring true democracy, freedom, and opportunity to the south. The fact that in the aftermath of this great Civil war, the southern aristocracy was able to rise up again, same as it ever was, is something that even present day Americans must still contend with and is a cancer upon this republic.