Naubad, Afghanistan—In a wheat field in northern Afghanistan this spring, beneath the Cretaceous convulsions of the Hindu Kush mountains, a village elder named Ajab Khan shared with me the unsentimental math of his region’s farmers. An acre of wheat, Khan said, yields $400. An acre of opium poppies yields $20,000. The people of his village, Naubad, had grown exclusively poppies until 2004, when the government of Hamid Karzai asked them to stop. In return, the government promised to hook up the village’s 200 or so homes to an electric grid; build a clinic, a school, and a communal well; and, in order to help the farmers take their crop to market, pave over the tentative parallel ruts that connected Naubad to the rest of the world.