In the last two decades the United States wasted trillions of dollars and much political capital on its War on Terror. George W. Bush, Tony Blair, Barack Obama, and their administrations can argue with some justification that by hounding terrorists they forced them to think more about survival than about acquiring nuclear bombs. They might thereby have saved the world from a nuclear 9/11. Since this is a counterfactual claim—“if we hadn’t launched the War on Terror, al-Qaeda would have acquired nuclear weapons”—it is difficult to judge whether it is true or not.
