I truly hope none of this ever becomes more than a debate and discussion online. I have two sons that I hope will die of old age in 50+ years.
That said, in my job I have contact with people all along the political spectrum. It seems to me only those on the far ends of both sides are so far apart that it appears to 've approaching battle lines. By far and away, most of us seem to be in the middle, living our lives, caring for our families, and while we may disagree about things, we aren't looking for that kind of fight.
If blood is spilled, where the lines would 've drawn would prove interesting. I know a lot of serious Democrat card carrying union brothers and sisters who have serious firepower in their safes, and no intention of giving it up because libs say so. I also know a lot of LEOs at local, state, and federal level who truly believe Molon Labe, 2A, and would hand in their badge if those lines were drawn.
Strategically, the centers of lib population are spread way out. Makes supporting each other pretty difficult. Especially if the Patriots in flyover country blow train tracks, highway bridges, etc. That all said, what about the rest of the world? If USA becomes the former United States, China has a whole lot of money invested in us staying United, making money, and paying them. Whole lot of other countries would sit up and take notice, maybe even choose a side. It wouldn't likely stay a domestic issue for long.