In my view, you have been arguing the reason for Southern secession, not the War. Clearly, the question of slavery and the political, economic and public safety aspects of slavery and/or its abolition were key determinants in the South's decision to secede. However, it had always been the South's intention to secede peacefully and pay just compensation to the Federal authorities for any debts owed.
Originally Posted by firstmdes
Similarly, Lincoln had made several public overtures, claiming it was not his intention to interfere with the institution of slavery but rather preserve the Union. If we are to accept his statements, slavery would have continued unimpeded. Had the South not seceded, we infer from Lincoln's commentary that slavery would have been protected.
Accordingly, the cause of the war is obviously divergent views over consolidated (Union) government versus the rights of states to secede from what they considered to be a voluntary compact.
Terry from Occupied Baltimore
"As I stood upon the very scene of that conflict, I could not but contrast my position with his, forty-seven years before. The flag which he had then so proudly hailed, I saw waving at the same place over the victims of as vulgar and brutal a despotism as modern times have witnessed."
Francis Key Howard, Ft. McHenry 1861