ISTANBUL — The shocking rebuke of Turkey’s governing party in Sunday’s mayoral election in Istanbul resonated as more than a yearning for new leadership in the nation’s largest city. It signaled mounting despair over the economic disaster that has befallen the nation under the strongman rule of President Recep Tayyip Erdogan.

Through the course of a 16-year run as Turkey’s supreme leader, Mr. Erdogan has time and again delivered on his promises of potent economic growth. Yet not unlike an athlete who puts up record-shattering numbers through performance-enhancing drugs, he has produced expansion by resorting aggressively to debt. He has unleashed credit to his cronies in the real estate and construction industries, who have filled the horizons with monumental infrastructure projects.

The bill has come due. Over the last two years, financiers have taken note of the staggering debt burdens confronting Turkey’s major companies and grown fearful of the increasingly dubious prospects for full repayment. Investors have yanked their money out of the country, sending the value of Turkey’s currency, the lira, plunging by more than 40 percent against the American dollar.

The result is inflation running at an annual rate of about 19 percent, besieging ordinary people and companies alike. Farmers are stuck paying sharply higher prices for imported fertilizer and fuel for their tractors. Families are paying more for vegetables and eggs. Factories are paying extra for imported components like electronics and parts. The official unemployment rate exceeds 14 percent.