On Christmas Day, 2009, twenty-three-year-old Umar Farouk Abdulmutallab attempted to blow up Northwest Airlines Flight 253 using explosives hidden in his underwear. A string of missed opportunities and errors by government security agencies culminated in what President Obama would declare a “systemic failure.” Is scanning everyone with expensive, high-tech equipment the best use of limited resources? Or should we use the information that we have—the knowledge that, while not all Muslims are terrorists, most terrorists are Muslim.