Two days after the Turkish military and allied jihadist forces took control of the Kurdish city of Afrin in northwestern Syria, Islamic State (ISIS) terrorists launched a major attack on Syrian regime forces in the eastern province of Deir Ezzor. The ISIS terrorists killed at least 25 soldiers and seized a large oil field. Around the same time, ISIS militants captured a strategic district in the suburb of Syria's capital, Damascus, where they killed more than 60 government troops. These two recent advances signal a possible return by the extremist group that only months ago was thought to be largely...