After weeks of uncertainty and foot-dragging, the Appeals Court this week made a critical ruling, setting the stage for a potential shakeup in Turkish politics that may block President Recep Tayyip Erdogan’s drive for an executive presidency. The court gave the green light for the Nationalist Action Party (MHP) to hold a convention requested by in-house dissidents seeking to remake the party, whose erosion in recent years has played directly into Erdogan’s hands. Leading the dissidents is Meral Aksener, a rare female heavyweight on Turkey’s political scene, whose fortunes may now change not only the MHP’s but also Turkey’s course.