In the past decade Pakistan has become a country of immense importance to its region, the United States, and the world. With almost 200 million people, a 500,000-man army, nuclear weapons, and a large diaspora in Britain and North America, Pakistan is central to the hopes of jihadis and the fears of their enemies. Yet the greatest short-term threat to Pakistan is not Islamist insurgency as such, but the actions of the United States, and the greatest...