Pulling out now would be utter madness. We won the Vietnam war, the Tet Offensive was a total total failure. But we gave up and left. The Vet Con were finished. The NVA was in full retreat. We effectively surrendered and left.
We can't make that mistake again.
This is why The US deserves a lot of respect from the outside world. American has got the experience in helping and developing democracy and liberty in countries where you could never predict democracy as a solution. This is the repertoire of American and British soldiers, we should be proud of participating in Afghanistan.