The US has no business being in Afghanistan. It is of little geographic or economic importance. Iraq would be valuable with it's oil reserves, but an impoverished country in the mountains is not worth anything. The only reason I can see that the war is justified is because of the WTC bombings.
An idea that I present is that like Vietnam, Afghanistan is an unpopular, and protested against, war. Even though Big Stick policy was carried on in ways by Obama, he also knows that the media turned that war on its head, and the soldiers should return. Pursuing diplomatic interests with Afghanistan is possible.