Bruce:
You open a larger can of worms than I am prepared to address at the time: the whole fate of the American experiment as a result of the secession, the War that followed, and all that has come since the War. I have sought to address the narrower questions, as I understand them, of slavery, union, and the War. What you seek to address is the entirety of the American scene since then. That's a huge question and while we have many points of agreement, I think that it's considerably more complex than you are suggesting. I think before we can most successfully address them we need to have a real handle on nineteenth century American history, including religious history. As I said, I appreciate much of what you are saying but would demur at points.
The question, for example, of whether the South not only had the right to secede but was right in seceding under the circumstances that it did is a huge one. I may be unconvinced that the South rightly seceded constitutionally, but I am not interested in making that argument here, which is a political and not a biblical argument. The issue of the use of force is not simply a matter for Lincoln but for Davis (those were federal forts, not state properties, that were the proximate cause of the war). These are exceedingly complex matters, the most difficult in our whole history, and need lengthy treatment, so I am reluctant even to raise them.
PBers should feel no need to come to definitive conclusions about these exceedingly thorny issues and should be wary of me or anyone else who offers dogmatic answers. We can be dogmatic about theology because we have a divinely inspired book from which we derive it. The same is not true of history, about which we who agree theologically may differ sharply. This is why we want clearly to distinguish the theological from other enterprises. Rable, in God's Almost Chosen Peoples, as does Noll (as did Lincoln in the Second Inaugural Address) well shows orthodox men on both sides seeking to justify their actions by appeal to heaven.
I agree, as Edward said, that we don't need to approach these questions merely from a 21st century approach. We need to approach them from the 18th and 19th centuries in the American context, having in view the whole situation and not simply taking the word, as it were, of the partisans of the conflict on either side. I think that there is more than one way to read back into these events. Much of our 21st c. conservative/libertarian approach is quite different from the feel and thought of the nineteenth century. I suppose that I've said too much already and will leave it there.