It started with a small protest over the decision to pave over a small park in Istanbul. But that decision and the Ankara government's heavy-handed reaction has sparked the most violent riots that Turkey has experienced in decades. Turkish Prime Minister Tayyip Erdogan, for years applauded as a moderate Muslim and pragmatist who has overseen his country's economic resurgence, is now widely seen as having lost touch with the masses of Turkish people and is feared to have embraced an intolerant and authoritarian agenda.

Mr. Erdogan has been in power for over a decade, leading the Islamic-based AK Party (AKP) to an ever-increasing share of the vote in three national elections. Throughout that time, opponents have tried to raise fears that his Muslim roots would clash with modern Turkey's secular constitution. He has, until now, turned back those criticisms quite successfully.

Instead, Mr. Erdogan practiced a moderate, practical political program that aimed to consolidate democracy — read: trim the power of the military, a powerful force in Turkey, which engineered four coups in the second half of the 20th century — and create political stability.