I must respectfully disagree. I think that the matter is a little more complicated.
First, the Southern Democratic candidate in the 1860 election was John C Breckinridge of Kentucky. He had become a fervent States Rights advocate in the 1850s, but he owned no slaves (Bell of Tennessee, the candidate of the Constitutional Union Party, who owned slaves, attempted to make an issue of this fact, arguing that he could protect slavery better than someone who did not own any). If slavery is the only reason, then why are the Southern Democrats nominating someone who doesn’t own any?
Second, Virginia, at a secession convention, voted by a 2-to-1 margin on April 4, 1961, to not to secede. Fort Sumter is fired upon on April 12. Lincoln called for troops to be furnished by the non-seceded states on Apirl 15, and on April 17, the secesion convention voted to secede, subject to a state-wide referendum, which approved secession in May.
The status of slavery had not changed between April 4 and April 17. Virginia’s actions indicate that, while the central question, slavery in itself was not the only issue.
Right.
And I think you're blowing smoke. All the nuancing in the world will not cause me to ignore the obvious.