dr,
Are you seriously suggesting America is on the brink of a civil war, with red staters using their guns against blue staters?
At present? No. There is some hope that American cultural schism over the past generation can be healed.
If the polarization continues without mitigation, however, I expect a civil war, or at least civil strife like a Rodney King riot X 10 in a number of large cities. I"d predict ruptures along predominantly ethnic-cultural lines. The ugliest of prospects is a multi sided, race/ethnicity based war on our soil.
The "red staters" would be less likely to slaughter the "urban elites" than such crooks already in the urban areas -- red state or blue state is irrelevant in this sense -- who have guns, and who will exploit their ability to use force if the "thin veneer" cracks. If you look at the thinly veiled racialism in the CT mindset, and the alleged appeal that holds on the storied "x % of the population" I'd say there is fertile mass psychological ground for a nasty acting out along those lines. What I can't fathom is what a catalyst, or series of catalysts, would be that line the factors up.
Hell, marksman, some street gangs already subjugate people via armed means in LA and Dallas now. Likewise in most major urban areas.
The information age seems to have had the effect of reinforcing tribal behavior -- generically -- and across the board social balkanization, an outcome at odds with the vigorous attempts to exploit the capacity to bring people closer together. The internet is a fascnating example of that dynamic in action each day.
Tipping point not yet reached in either direction, and I am not sure how far from one we are.
If civil strife turns to civil war, I suspect you'll see the US National Guard fracture the way the Iraqi National Guard and Army fracture, and dissolve as an effective fighting force. Mass desertions and AWOL counts would be the first symptom of that internal collapse. What would happen in the US regular Army would likely be what happened in the civil war: some would remain true to the colors, and some would take R. E. Lee's course, and return home.
DR