... If Syria’s largest city is surrounded by government troops, the strategic situation in Syria could change very rapidly for the worse, not only for Syrians, but also for Turkish President Recep Tayyip Erdogan—and for the Obama Administration, which has banked heavily on the crumbling peace talks to end five years of civil war and an expanding presence for ISIS amid the chaos. The encirclement would also be a major strategic advance for Russian President Vladimir Putin, who has drawn his forces in Syria, but has also been helping the Assad regime conduct more focused military operations under a two-month...