Three months after its “split” from al Qaeda, which in reality is simply a feint, Jabhat Fateh al Sham (JFS), formerly known as Jabhat al Nusra, may pose a more significant long-term threat to the West than the Islamic State in Iraq and Syria (ISIS). While the West targets ISIS, JFS is quietly laying the groundwork for al Qaeda's resurgence by “hunkering down,” rebuilding, and repositioning itself along several fronts. This should come as no surprise — al Qaeda and its affiliates are nothing if not resilient. With approximately 10,000 fighters, JFS is now both the largest al Qaeda franchise...