Haha, citizens are going to rise up against the government, yeah that train has left the station about 150 years ago. Look at how quick any protest is squashed. They'll put up with it for a little bit so the people can left off steam and feel like they have rights but once they've had enough the hammer is coming down.
That's stupid, look at Vietnam or Iraq. Guerrilla warfare... On top of that, the citizens of the United States are armed 10x better than the Vietcong or Al Qaeda. That fact alone helps keep tyranny in check.
Plus, the military would almost entirely fight on the side of the people...
The second amendment is just as relevant now (if not more so) then it was then.
I would never ever feel secure living in a society where only those that would do others harm were armed.