Charles Oliver, writing for Reason, reviews Charles Adams‘ book When in the Course of Human Events: Arguing the Case for Southern Secession:
Openly partisan to the South, Adams believes that the Civil War truly was one of Northern aggression. He believes that the Southern states had the right to secede and he believes that the war's true legacy is the centralization of power in Washington and the deification of the "tyrant" Abraham Lincoln. To this end, he collects all the damaging evidence he can find against Lincoln and the North. And he omits things that might tarnish his image of the South as a small-government wonderland.
Thus, we hear of Lincoln's use of federal troops to make sure that Maryland didn't secede. We don't learn that Confederate troops occupied eastern Tennessee to keep it from splitting from the rest of the state. Adams tells us of Union Gen. William Sherman's actions against civilians, which he persuasively argues were war crimes. But he doesn't tell us of Confederate troops capturing free blacks in Pennsylvania and sending them south to slavery. Nor does he mention the Confederate policy of killing captured black Union soldiers. He tells us that Lincoln suspended habeas corpus; he doesn't mention that the Confederacy did also.
Before and during the war, almost every Southern political leader explicitly said the Southern states seceded to protect slavery. Perhaps the most famous statement came from Confederate Vice President Alexander H. Stephens. In 1861, in Savannah, Georgia, Stephens bluntly declared that slavery was "the immediate cause of the late rupture and the present revolution." He said the United States had been founded on the false belief that all men are created equal. The Confederacy, in contrast, had been "founded upon exactly the opposite idea; its foundations are laid, its cornerstone rests, upon the great truth that the Negro is not equal to the white man; that slavery, subordination to the superior race, is his natural moral condition."
Well, Adams says in effect, Stephens was lying. Southern leaders knew that people couldn't be roused to fight over something so unappealing as tariffs. So they whipped up a fear that slavery was at stake. "Men will not willingly, and with zeal, die for an economic purpose, but they will die for some 'cause' that has a noble purpose," writes Adams, neglecting to lay out precisely why slavery was so noble. Indeed, Adams' thesis is a completely unsatisfying one. Even if true, he can't answer an important question: Given that most Southerners didn't own slaves, why was this a more attractive issue for raising fighting passions than tariffs? Why would so many die with "zeal" for a "noble" purpose from which they were excluded? After all, less than one third of Southerners owned slaves.
Why do people try to deny the importance of slavery to the Civil War? In the past, it might have been racism in many cases — but probably not as often now. More common motives might be to whitewash the South (if South was defending something less immoral than slavery, then they don’t look so bad) or perhaps to vindicate the South’s alleged motives. In this case, the cause of “states’ rights” is often invoked as the reason the South seceded and went to war. Arguing that as the “real” cause can allow a person to argue that states’ rights should be considered more important that they currently are. By framing the North as the “anti-states’ rights villains,” not only does the South look better but the causes of states’ rights does as well.