All right, what author passes for an "historian" in your school, some neo-Confederate whitewasher or Howard Zinn?
We have a quote addressed to people who believe that slavery was not the cornerstone of the Confederacy. You might also have a look at the Confederate Constitution, article I, section 9, paragraph 4.
Yeah, it was about states' rights to protect slave owners rights. "All right, what author passes for an "historian" in your school..." Thomas DiLorenzo, no doubt.
Zinn is a bona fide historian, LX, however much you disagree with him. He is a revisionist, not a negationist or a denialist.