Preemptively, unfiltered, even crossing such a threshold, it would not be possible even to imagine that martial law, union vise, or separable by state would not preceede such state of affairs. After that failing, would-could the above scenarios be envisioned to seek more drastic resolution.
An objective issue would need to be raised, such as slavery, without which no one would rally expressly to either side. This question predominates before.
The simplified version is, could civil war actually break out even with the effects that an application of martial law, that would be applied to any effort on part of individual states threatening to ceceede, by virtue of such fragmented issues as : immigration, white nationalism, economic inequality, diversively widening differences between the rich and the poor, etc.
If after all this failing, could national guarding of national unity guarantee successfully prevention of a civil war? These intervening questions need resolution, and if failing, the questions could become viable
Just a note : I am tempted to answer the pointed questions. and I can see that the assumption is that all failed, however it was compelling to insert the above variables, in order to indicate the relationship between such scenarios as necessarily based on the idea and the constitutive force between them. In my nind at least, they are a sine quo non.
In addition, could the historically new method of dealing with national strife. be exported into an international theatre, which was not available in Lincon’s time prefigure? (Wag the dog)
And the news of the new Iranian clouding came after this prefiguration. That is most expedient, in this age of op ed via pop psych. Who could ever know the Real facts out there?