Afghanistan: for what?

Once again today the story is the same: Canadian troops killed by a roadside bomb in Afghanistan.

Except it's not the same, this time they were in the Nyala, a vehicle that was supposed to be best-in-class for protecting against IEDs and the like. They had Scott Taylor of Esprit de Corps on the radio this afternoon and he opined that Afghanistan is not a place were we can "win" in any conventional military sense. He then went on to say that this recent attack had occured in any area that had been pacified last fall and was thought to be friendly to NATO forces.

While the supposed aims for any NATO mission sound noble I just cannot believe that we can accomplish them in any meaningful fashion. So what good are we doing if the Taliban (or whoever else dislikes us) can operate with impunity outside the perimeter of NATO's bases?