Let's say the states actually do (secede?) break away from the rest of the country and begin inciting violence. Will the Military have to intervene and kill their own people, like what is going on in Syria? If that does come to that, I bet you the rest of the world, who already don't think very well of us, will see that we are just a bunch of hypocrites.
If you're a solider who was deployed to a state that rebelled and you are ordered shoot to kill. Would you shoot and kill your countrymen or disobey orders and face a court martial?