We are experiencing the sort of failure there that others have before us. It is not at all clear that dealing with Al Qaeda is getting done--witness the training and related terrorist activities coming out of Yemen, a supposed ally. Ft. Hood, XMas airplane bomber, to name but two.
This stuff is very difficult and complex, but I think that we just have to let go of Afghanistan and deal with these challenges another way. Since it appears that what there is of Al Qaeda in that part of the world is actually on our supposed ally Pakistan's side of the border, it calls into question just why we are putting so much effort next door.
There are many dysfunctional countries in this world.
Terrorists are a threat, and need to be shut down to the extent that is humanly possible.
More and more, I do not see US military initiatives as the means to protect this country from the types of terrorists who threaten our safety.