“It’s not true that Turkey is becoming less secular,” said Ezgi Yagmur Kucuk, 20, a trainee anesthetist who does not wear a veil. “Everyone can believe whatever they like.”

Others, however, see an attempt not just to promote freedom of religion, but to ensure its primacy. According to Kerem Oktem, the author of “Angry Nation,” a history of contemporary Turkey, the country is “not continuing along a process of secularization — it’s going into a post-secular context.”

Still, Turkey is not considered likely to morph into a second Iran. The country’s vexed relationship with secularism also predates Mr. Erdogan’s tenure.

Technically, mosque and state were never completely separated in Turkey, even during the days of Ataturk. Instead, religion was placed under the control of the state. The process of legitimizing Islamic thought was in part begun during the rule of Kenan Evren, the army general who took power in a coup in 1980 and who viewed Islam as a potential buffer against communism.

To add to the complexity, Mr. Erdogan’s party — the Justice and Development Party, or A.K.P. — has a confusing relationship with Islamism, or the belief in a society governed according to Islamic law. It does not call for the application of Shariah law.

Its leaders have historically denied they are Islamists, preferring instead to be known as conservatives. Unlike the political wing of Egypt’s Muslim Brotherhood, a group to which the A.K.P. has sometimes been compared, several of its female lawmakers are unveiled.

One of Mr. Erdogan’s best-known supporters, Cem Kucuk, an outspoken commentator, has even called for hard-line Islamists to be expelled from the party.