Last December, Brynjar Lia, an analyst at the private Norwegian Defense Research Establishment, came across a 42-page document in Arabic on the Global Islamic Media Web site, one of many Islamist sites that he routinely surveys for his research on terrorism. Entitled "Jihadi Iraq: Hopes and Dangers" and produced by someone claiming to be part of the Mujahideen Services Center, the document outlined a strategy for breaking up the U.S.-led coalition by directing "painful strikes" at America's allies, particularly Spain. Although impressed by its sophisticated analysis of Spain's domestic politics, Lia concluded that the paper's focus on jihadist activities inside...