Repeated endlessly, but doesn't actually work. They already had slavery. They weren't leaving to get something they already had. They were leaving to get something they didn't already have.
They launched their war to further that aim.
Because by leaving they were going to get more slavery?
If the Republican party with its platform of principles, the main feature of which is the abolition of slavery and, therefore, the destruction of the South, carries the country at the next Presidential election, shall we remain in the Union, or form a separate Confederacy? This is the great, grave issue. It is not who shall be President, it is not which party shall rule – it is a question of political and social existence.
;Alfred P. Aldrich South Carolina politician
The anti-slavery party contends that slavery is wrong in itself, and the Government is a consolidated national democracy. We of the South contend that slavery is right...
—;Laurence Massillon Keitt, Speech to the House January 1860
Then after the election, and before Lincoln was inaugurated, they kept saying it was about slavery.
Resolution to Call the Election of Abraham Lincoln A Hostile Act That this General Assembly is satisfied that Abram Lincoln has already been elected President of the United States, and that said election has been based upon principles of open and avowed hostility to the social organization and peculiar interests of the slave holding states of this Confederacy.
Resolved, that it is the sense of this General Assembly that South Carolina is now ready to dissolve her connection with the government of the United States, and earnestly desires and hereby solicits the cooperation of her sister slave-holding states in such movement.
Resolved, that the Governor be requested forth with to forward a copy of the foregoing resolutions to the Governor of each of the slave-holding states of this confederacy, with the request that it may be submitted to their respective Legislatures.
November 9, 1860
Our people have come to this on the question of slavery
— Laurence Massillon Keitt, South Carolina secession debates, (December 1860)
Heck, even the clergy in South Carolina chimed in.
Anti-slavery is essentially infidel. It wars upon the Bible, on the Church of Christ, on the truth of God, on the souls of men.
—;Southern Presbyterian of S.C., 10 November 1860
The triumphs of Christianity rest this very hour upon slavery; and slavery depends on the triumphs of the South... This war is the servant of slavery.
—;John T. Wightman, The Glory of God, the Defence of the South, (1861)
I keep looking at what the South Carolina rebels said and wrote about why they were rebelling and this darn slavery thing keeps coming up.
Works very well except for folks like you and Mr. Olive.
They already had slavery. They weren't leaving to get something they already had.
And a newly elected administration bound and determined to keep it from expanding. With every newly admitted state the power of the slave states would decline. Better to leave and establish there own country where the idea of a non-slave state wasn't something they had to worry about.
Because by leaving they were going to get more slavery?
That was one of their aims, yes.