How would a soviet style implosion of the US work in real life? A civil war is far more likely and we already have historical precedence for that.
And your AI robot cybernetic splinter group thing sounds a lot like the biblical story of Noah than anything that's based on science or you know facts.
Chaotic coincidences,
because the empire is too large to control all of its interests.
Could have been avoided - too much money to be made in the various stages of it not being avoided.
The US and particularly its armed forces don’t look at all like the 1800s, so another civil war of that nature is not possible. Sabotage, terrorism and political violence could be a new form of civil unrest, but full out civil war without a divided military with entire divisions defecting, is very unlikely.