Follow along with this bit of twisted logic, the only way that we keep the Taliban and Al Queda forces fighting is for them to be alive. The local Afghanis will turn at the drop of a hat, however Osama's boys will not. Using sat intell and on the ground intell we have followed them around the country. We have observed their troop deployments and using a newly armed N.A. went after them. We used our air power to turn the locals as we did in Desert Storm ie they see us and can't surrender fast enough. We deplete their forces with a minimum of ground action taking place. We've been herding them into a central location making it easier for us to take out the guys that we're really after and pretty much insulating the populace from total warfare (see winning hearts and minds).
After only a couple of weeks we have the terrorists and their handlers in two places, Kunduz and Khandahar. Now we don't have to go into every nook and cranny looking for them. Meanwhile, the peaceniks, the bleeding hearts, and the Arabs can't go off the deep end screaming stop and build any momentum against the war.
You've now managed to put your opposition in a box, and can prosecute the war on your terms with little or no loss of political capital. When the time is right, you strike the fatal blow (we went after Omar yesterday, Osama can't be too far off). Take out the remaining terrorist forces, the remaining Taliban, and finally Osama. Game, set, and match in Afghanistan. Time to aquire the next target.