(JNS) Any notion that the worst days of Islamist terrorism are long behind us was brutally shattered at Kabul Airport on Thursday, as twin bombs ripped indiscriminately through Afghan civilians and U.S. and other foreign servicemen trying to complete the desperate evacuation of thousands of people for whom Taliban rule represents the most terrible fate.

Gen. H.R. McMaster, a former U.S. national security advisor who served as deputy commander of the international force in Afghanistan, put it succinctly in the hours that followed the bloodshed in Kabul. “Maybe this moment is the time that...