“There is a new class that has arisen in his 20 years, and their interests are overlapping with Erdogan’s,” Mr. Beki said. “It is expecting them to act against their interests to expect them to go against the A.K.P. and Mr. Erdogan.”

Mr. Erdogan’s critics note that Turkey’s gross domestic product began declining about a decade ago, and annual inflation, which surpassed 80 percent last year, has left many Turks feeling poorer. Most economists say Mr. Erdogan’s unorthodox financial policies have exacerbated the crisis.

During his years in power, the president has consolidated his control over much of the state, tilting Turkey toward autocracy, while frustrating the United States and other NATO allies by maintaining a close relationship with President Vladimir V. Putin of Russia after his invasion of Ukraine last year.

Kayseri, in central Turkey, has long been a stronghold of Mr. Erdogan, voting for him and his party, often overwhelmingly so, in every election since 2002. Recent conversations with more than two dozen voters there showed that many still admire his leadership while others simply can’t imagine anyone else in charge.

When Mr. Erdogan appeared on the national scene as a young, dynamic prime minister in 2003, he and his party promised competent governance, reliable services and economic growth.