China had been engulfed by civil wars more than once and each time coalesced back into the Empire. The trick is, empires show better survivability in such modes, while the US hasn't yet completed transformation from the defective Republic into the ailing, but sane, Empire. Possibly it never will, because the world history knows examples of states that failed irreversibly during uncomplete structural transformations, e.g., Carthage, Golden Horde, Burgundy, or more recently Yugoslavia and Ukraine.