Dean Acheson, secretary of state to the former United States president, Harry Truman, liked to quote a friend who said that being in government made him scared, but that being out of it made him worried. To those of us not privy to the hidden complexities of NATO’s military intervention in Afghanistan, the situation in the country – and indeed across Central Asia – is extremely worrisome.

As Afghan President Hamid Karzai is said by his critics to be on the verge of casting his lot with Pakistan and the Taliban, the Pentagon has signaled its fear...