Start using overwhelming force and we will have victory. You can't defeat your enemy with a shove. Blunt force trauma is necessary.
They painted themselves into a corner though. Aggressive campaigning could win the war militarily if coupled with other strategies (including dissolving the Iraqi government and installing a military governor), but it would show the raison d'etre of the war, establishing a democracy in Iraq, to be bunk. Bush made the mistake of justifying the war by gimmicks before it was won on the ground. We'd lose just as much face doing what we have to do to win as we would by letting it go.
If only they had crushed the rioting after the fall of Saddam. But they didn't, and it showed the Iraqis that we did not have what it takes to undergo a successful occupation and pacification of a large country.
Amazing that people actually think you can win a war without using overwhelming force.