U.S.-backed forces in Syria have expelled the Islamic State from its last outpost, and proclaimed the defeat of ISIS. The self-declared caliphate at one point controlled a territory the size of Portugal, home to 7.7 million civilians. The Syrian Democratic Forces (a Kurdish and Arab coalition backed by the U.S.) announced that anti-ISIS fighters had accomplished the "total elimination of so-called caliphate and 100 [percent] territorial defeat of ISIS." But ISIS's territorial defeat does not mean the group has been totally eliminated as jihadist fighters are still active in the region, and defense forces must remain diligent to prevent a resurgence.