The question is, on whose side will the Armed Forces intervene?
Most of the line troops might be conservative, but a lot of officers, esp. in senior ranks are commie pinko libs, thanks to the selection process.
If civil war comes, it may not be perceived as right versus left, conservative versus liberal, but as revolutionaries/bandits/terrorists/thugs versus law and order and the established way of life and governance. Whoever starts the war will be so demonized that the military will move against them without much hesitation.
In other words, for every civil war in recent history with two equally matched sides, there have been plenty of anti-terrorist, mopping-up operations, and what happens in future America might be like that. Whoever takes up arms first is likely to be considered a threat to public order, isolated from and opposed by the rest of the country.
There was a process in the Vietnam war called fragging which to care of officers with high a-hole content