the American system is too compartmentalized to be a simple "us vs them" rebellion, the various divisions and departments would inevitably side with one faction or the other, the military at large would probably be split with the higher ranking "men of piece" that obtained their rank through politics siding with the government, and a majority of the lower ranking fighting force siding with the rebels. neutrality would be impossible as at some point they would be ordered to attack U.S. citizens, at which point they would be forced to choose one or the other.
this is assuming this rebellion is a normal regimented rebellion like we have seen in the Arab spring, which would be unlikely. a more likely form for any rebellion would be a more tech savvy one, focusing on cyber attacks and assassinations. this would wind up being more of a duel between ever more fierce anti-terrorist crack-down with more and more freedom and rights being rescinded for "national security" and more and more citizens inevitably joining the resistance as fewer and fewer options are available. Obama has already set a precedent for using combat drones to kill U.S. citizens without trial, and the national defense act he amended declared the U.S. a battle ground, meaning that it is legal for him to order the army to perform military action on American soil, which always holds the potential for being used against U.S. citizens. honestly i don't see it as all that far off, the pieces are in place, all that's missing is something to motivate the people to action.
it would be long and bloody, and by the end of it any and all freedoms would have long faded away in order to crack down on the growing resistance. it would effectively end in an eternal cycle of unorganized cyber attacks, then organization of a movement, then the capture and execution of its leaders, and then more disorganized cyber attacks, with bombings sprinkled here and there. eventually one of the other super-powers would side with one of the sides and use them to set up a puppet government, and since most of the other superpowers that would want to do such a thing are communists they would probably side with the government, since it would already be a socialist dictatorship by then, sculpted by the Occupy movement, lobbyists, corrupt officials and your standard "soccer mom" crowd that believes that anything not covered in pillows or containing more than a single grain of sugar should be illegal for our own good.
despite what many seem to think, there is absolutely no chance of any dictatorship forming from the right wing for the simple reason that they actually want the citizens to have access to fire arms, which is the biggest mistake any potential dictator could make. any party that supports rendering me defenseless against the government, however, has me worried, especially when they think the answer to every problem is "more government, more regulation, more red tape"
