Turkish President Recep Tayyip Erdogan Murat Kaynak | Anadolu Agency | Getty Images

In Western capitals a decade ago, Turkey’s now-paramount leader, Recep Tayyip Erdogan, held promise as a potential beacon of democracy for a region rife with religious conflict. Turkey was a stalwart NATO ally bridging Europe and the volatile Middle East. As Mr. Erdogan sought to secure a place for his country in the ranks of the European Union, he presented himself as a moderate and modernizing Muslim leader for the post-9/11 age. He catered to perceptions that Turkey was becoming a liberal society governed by tolerance and the rule of law. But that was before Mr. Erdogan began amassing supreme powers, and before his brutal crackdown on dissent following an attempted coup two years ago. It was before Turkey descended into a financial crisis delivered in no small measure by his authoritarian proclivities and unorthodox stewardship of the economy. Whatever was left of the notion that Mr. Erdogan was a liberalizing force has been wholly extinguished. For the West, Mr. Erdogan has devolved from a righteous hope — would-be proof that Islam and democracy can peacefully coexist — into another autocrat whose populism, bombast and contempt for the ledger books have yielded calamity. Regional experts contend that visions of Turkey’s leader as an agent of liberal progress were always fantastical. Mr. Erdogan — who served as Turkey’s prime minister for 11 years before becoming its president in 2014 — forged his political career as an Islamist intent on challenging the strictures of Turkey’s state-imposed secularism. His early democratic reforms and assertion of civilian control over the military were largely about winning the welcome of the European bloc while enabling Turkey’s Muslim populace to practice its religion free of state interference. “For us, democracy is a means to an end,” Mr. Erdogan once declared. History is full of examples of Western nations — especially the United States — projecting their aspirations and values onto foreign leaders with their own objectives. In its effort to prevent China from falling under the control of Communists, Washington backed the Chinese Nationalist general Chiang Kai-shek, celebrating him as a courageous hero even as he brutalized opponents and profited on the spoils of American support. In Vietnam, Afghanistan and elsewhere, the United States cast flawed figures as veritable George Washingtons before writing them off as corrupt tyrants.

“This is a classical case of populism.It can get you growth for some time, but there’s a bill that comes due. And when the bill comes due, populists tend to get more authoritarian and oppressive.” Jacob F. Kirkegaard a senior fellow at the Peterson Institute for International Economics