Its really a police mission.
That should be handled by the locals.
Much like Iraq has been handled by the locals, fairly well so far, everything considered.
IMO, our troops should be brought home now. The Afghan government, the Taliban, and Al Queda should be placed on notice that if there are any further instances of terrorism that is traced to any group in Afghanistan the U.S. WILL NOT PLACE BOOTS ON THE GROUND, but will bomb the crap out of Afghanistan, and to hell with collateral damage.