There you go again Lampster. The hell it was about any idea of Southern independence. It was about the right to base an economic system based on the use of slave labor and it started a war to achieve that end. war , by the way, it had every intention of winning.
That is exactly what it was about. They had slavery while they were in the Union. Lincoln was going to guarantee that they could keep slavery as far as the eye could see, if they just remained in the Union.
The issue was about them remaining in the Union, not whether or not they would continue having slavery.
Independence was in dispute. The Continued legality of slavery was not in dispute.