The group has gone underground. It’s time to think about where it might show up next.
The Islamic State burst onto the world stage in 2014, capturing vast stretches of Iraq and Syria, brutally and publicly killing Western prisoners, and declaring itself a new pan-Islamic caliphate. President Obama announced an American effort to roll back and eventual defeat the Islamic State, and enlisted an international coalition of Arab and Western powers to accomplish that goal. This effort has, in turn, raised a host of new questions: about effectiveness and commitment, about international law, about presidential authority, about the interpretive limits of an out-of-date domestic authorization for the use of force, and about the general viability of American policy in the region.