These people have a history exponentially longer than the existence of the US of fighting invaders. They wont quit, they live there. Doesnt matter how many you kill, how many McDonalds you set up for them to work in, they are religious and tribal zealots who will not stop fighting. Its in their culture to oppose that which is being forced upon them. They do not want democracy, and the only way to control them is to be as vicious as Saddam was and be prepared to use that tactic for the length of whatever "government" you desire to be in place. You cannot stop a determined insurgency by trying to kill all the insurgents. Once again THEY LIVE THERE.