God I hope not. I really really hope not. The 19th century US Civil War was an exception because it was economic, so while it was gory it wasn't barbaric.
Tribal civil wars are barbaric. They are not fought with weapons, they are fought with genocide, torture, slavery, and mass rape. Humans in a state of a true civil war are not rational any longer, they are pure id.
Two things about that. (1) Mass suffering on a scale only China, Russia, and Africa have ever seen. (2) Who says we win? US territory commands a nuclear arsenal and the good guys are all concentrated in a handful of cities. The Morlocks are perfectly capable, technologically and psychologically, of killing 50M of us by pressing a button. They'll just tell themselves God told them to. Even if the Eloi could do that psychologically (and I'll bet we could -- it's to save women and minorities from misogyny and racism WE HAVE NO CHOICE ARGLE BARGLE!!!!) there is no way to mass murder the rurals -- they are too spread out, and their females 12-52 are mindless larvae-extruding meat sacks so they just make more.