Truth be told, there's not much we can do to stop Al-Qaeda from setting up shop in places like Yemen, Sudan or Somalia. In the case of Yemen we're working with the government there to shut down terrorist cells, albeit fairly discretely. When you're dealing with a mess like Somalia, well then I don't know. Still, if the terrorists decide to play whack-a-mole with us and a mole pops up in Afghanistan....we don't have much choice but to whack it. Well, I don't know. But a lot of experts seem convinced that although we can't stay in Afghanistan forever, we still haven't hit rock bottom yet and that it's important to keep trying while we can still make a difference. One thing on our side is that the Taliban are hugely unpopular with Afghans, and as time goes by more institutions and infrastructure will rise up to allow them to resist the Taliban.