Nothing would happen. The people in the government now are so powerful, so criminal, so determined to crush any opposition, they would do it with weapons that no ordinary person in this country could ever hope to own.
It is functionally a tyrannocracy far more powerful then even the Communist slave states and brooks no opposition. Seen anyone thrown out of the government lately for going after Tea Party activists, or elected Representatives?
The bureaucracy now plans to wipe out any possibility of armed resistance which was considered a Right by the Revolutionaries. The Judges are bureaucrats: once appointed, they never go away - and anyone who tries to make them go away because of their acts will immediately find themselves up against a wall of grim, armed men.
The government has expanded and ossified into an organized gang that regards the citizenry as their plantation workers, good only insofar as they can produce wealth to be confiscated. This is simply Feudalism of a form and supremacy unseen in human history.
The Second Amendment was written to prevent exactly that. It is all but extinct. The next step by the Bureaucracy will be to permanently extinguish even that small glimmer of hope, and it will be done with the threat of force so horrific that no man with a peashooter would consider opposing.
No lessons learned from our experiences in Afghanistan and Iraq, I see.