I could imagine there being a war against the people who think “educated” is an insult and those who don’t. There’d have to be a pretty big spark to light that fire, though, I don’t think an assassinated Obama would do it. That would just send us into despair, not righteous anger.
Since there’s only been one US civil war, it’s hard to extract much data (so far, 100% of civil wars have been about slavery), but I don’t know if one would even be possible now. The country was smaller and didn’t have the complex and domineering military system we have now. Then it was just farmers with guns vs farmers with guns. A civil war now would be farmers with guns vs the National Guard, Army, Marines, and Air Force (the Navy could sit this one out).
This is why you don’t see many civil wars in military-industrialized countries. If anything, you see military coups. How would you get the entire military to turn against the rest of the government in the US?
I suppose if you had one president that was a real gung-ho military man and everybody with a uniform loved him, and then after him was a hippy-dippy liberal president who wanted to dismantle our entire military or something, with a decent helping of Limbaugh-fueled anti-government sentiments and that ex-president getting vocal in public opposition of the current president, he could possibly get some of the top US commanders to break from the pentagon and go (ahem) rogue.
Basically, rebels vs the empire.
Edit: To reiterate my last point, consider simply the use of the phrase, “I want my country back” and the type of people prone to saying it.