Ummmmm....communism is complete governmental control of all industries. The former USSR and East Germany did not melt down due to anarchy. China of today is not in a state of anarchy. The only thing communism leads to is a lot of hunger and destitution.
Oh, and let there be a civil war...it'd be entertaining as fuck....and would be over very soon. What are a bunch of gun owners going to do against tanks and predator drones and police with miitary-grade equipment? Answer....nothing.
Which make me wonder just how much of the military would participate?