A friend of mine spent several years in Afghanistan working as a doctor attached to the U.S. forces. He told me some pretty harrowing tales about his tour o' duty here but the thing I remember most is when he said, "Staying there is a disaster. Leaving there would be a disaster. Nothing about the country is not a disaster." I think that's proving to be the case.
I seem to recall a lot of politicians of both parties saying we should just get the hell outta there. So we tried to get the hell outta there and they're not happy about that.
The two pundit/experts I look to on this kind of topic are Daniel Larison and Fred Kaplan. You can read what each has to say.