Slavery wasn't the only issue discussed in those secession conventions, not by a long shot. Since the North wasn't fighting to end slavery and since the South could have maintained their peculiar institution by remaining in the Union...you know what that means, right?
It was by far the single most important reason for the Southern rebellion to the exclusion of almost everything else.
Since the North wasn't fighting to end slavery and since the South could have maintained their peculiar institution by remaining in the Union...you know what that means, right?
It means your ignoring history. The South was not interested in remaining in a Union that wanted to limit the expansion of slavery. Safeguarding slavery were it existed was only part of the loaf, the South wanted the right to take their slaves into every state and every territory as Taney ruled in Dred Scott. They ensured that right was protected in their own Constitution.