When Turkey finally agreed to join U.S.-led efforts to fight Islamic State, Ankara was supposed to make the battle against the extremist group more effective. Yet within days, Turkey's president, Recep Tayyip Erdogan, bombed not just Islamic State forces but also, with even greater fervor, the one group showing some success in keeping them at bay: the Kurds.
The United States miscalculated by bringing in Erdogan. Turkey's embattled and volatile leader looks far less interested in combating Islamic State than in reclaiming his power at home. Erdogan's personal agenda, however, cannot be allowed to alienate U.S. partners and prolong the conflict.
Washington's first priority here should be to preserve its constructive alliances with Kurdish groups in the fight against Islamic State. It must also prevent Turkey from further undermining the key strategic goal of defeating the jihadists.