...Among other lessons of 9/11, we have learned the cost of squeamishness that prevented closer scrutiny of young Arab men entering the country even when their behavior raised suspicions.... [A]n airline ticket-taker recalls being stunned by the strange look on the face of customer Mohamed Atta--particularly the unsettling fury the man exuded. Still, he could not bring himself to raise any alarm: indeed, when he heard later that the plane Atta was on had been one of those that crashed in the terror attacks, the agent felt terrible. Terrible because he had been suspicious of the passenger and thought he...