[Angus]

Unfortunately, having now poked our noses into their country and interfered with their politics and culture, we can't just withdraw overnight, since there would be absolute mayhem (of our making) being wreaked on innocent Afghans by the Taliban and other insurgents. It is in the interests of future stability in the Middle East to make sure that the radicals and terrorists do not gain control of Afghanistan since this would be extremely dangerous for the West. We created the mess, so we have to clean it up before we leave, that's the problem and the reason for a five year time line.