It is only very recently, as the debate over the confederate flag has been renewed, that I have come to realize just how deeply the myth that the Civil War wasn't really about slavery has taken root. I had always been under the impression that people who sported the flag were fully aware that it was popularized by 20th century segregationists, but insisted that it wasn't really about the belief that black people were property as an easy means of avoiding confrontation. But as I've looked around these last few weeks, it has become more and more clear: people really believe this stuff.
Which is strange, because the confederate states were pretty clear about the reason for their treason, and there was no "not really" about it.
Four confederate states -- Mississippi, Georgia, South Carolina and Texas -- issued declarations of secession in order to expound upon their reasons. Their causes were slavery, slavery, slavery and slavery.
Mississippi kept it simple:
Our position is thoroughly identified with the institution of slavery - the greatest material interest of the world... [The north] advocates negro equality, socially and politically, and promotes insurrection and incendiarism in our midst.
Georgia's declaration, on the other hand, managed to use various forms of the word "slave" or "slavery" 35 times. Here are just a few of the mentions:
The question of slavery was the great difficulty in the way of the formation of the Constitution. While the subordination and the political and social inequality of the African race was fully conceded by all, it was plainly apparent that slavery would soon disappear from what are now the non-slave-holding States of the original thirteen....
[The Republican Party] entered the Presidential contest again in 1860 and succeeded.
The prohibition of slavery in the Territories, hostility to it everywhere, the equality of the black and white races, disregard of all constitutional guarantees in its favor, were boldly proclaimed by its leaders and applauded by its followers.
With these principles on their banners and these utterances on their lips the majority of the people of the North demand that we shall receive them as our rulers.
The prohibition of slavery in the Territories is the cardinal principle of this organization.
South Carolina was big on property rights, and by "property," they meant "people":
The right of property in slaves was recognized by giving to free persons distinct political rights, by giving them the right to represent, and burthening them with direct taxes for three-fifths of their slaves; by authorizing the importation of slaves for twenty years; and by stipulating for the rendition of fugitives from labor.
We affirm that these ends for which this Government was instituted have been defeated, and the Government itself has been made destructive of them by the action of the non-slaveholding States. Those States have assumed the right of deciding upon the propriety of our domestic institutions; and have denied the rights of property established in fifteen of the States and recognized by the Constitution; they have denounced as sinful the institution of slavery.
Compared to Texas, the other three were just beating around the bush. Here's a little snippet of its long, frothing white supremacist diatribe, which I really do insist you read in its entirety:
[Texas] was received as a commonwealth holding, maintaining and protecting the institution known as negro slavery - the servitude of the African to the white race within her limits - a relation that had existed from the first settlement of her wilderness by the white race, and which her people intended should exist in all future time...
[Northerners proclaim] the debasing doctrine of equality of all men, irrespective of race or color - a doctrine at war with nature, in opposition to the experience of mankind, and in violation of the plainest revelations of Divine Law. They demand the abolition of negro slavery throughout the confederacy, the recognition of political equality between the white and negro races, and avow their determination to press on their crusade against us, so long as a negro slave remains in these States...
We hold as undeniable truths that the governments of the various States, and of the confederacy itself, were established exclusively by the white race, for themselves and their posterity; that the African race had no agency in their establishment; that they were rightfully held and regarded as an inferior and dependent race, and in that condition only could their existence in this country be rendered beneficial or tolerable.
So, when compelled to declare their reasons, four out of four confederate states went pretty big with the slavery angle.
Even among the states that didn't issue accompanying declarations, a few were still able to work references or allusions reaffirming slavery into their ordinances of secession. Virginia lawmakers, for example, lamented, "the oppression of the Southern slave-holding States."
Alabama was more blunt:
It is the desire and purpose of the people of Alabama to meet the slaveholding States of the South, who may approve such purpose, in order to frame a provisional as well as permanent Government.
So, if you're one of those people who goes around saying that the Civil War was fought over anything other than the belief that white men should be able to own black people... you should probably stop doing that.