ISTANBUL — A Turkish newspaper reported that an American academic and former State Department official had helped orchestrate a violent conspiracy to topple the Turkish government from a fancy hotel on an island in the Sea of Marmara, near Istanbul. The same newspaper, in a front-page headline, flat-out said the United States had tried to assassinate President Recep Tayyip Erdogan on the night of the failed coup.

When another pro-government newspaper asked Turks in a recent poll conducted on Twitter which part of the United States government had supported the coup plotters, the C.I.A. came in first, with 69 percent, and the White House was a distant second, with 20 percent.

These conspiracy theories are not the product of a few cranks on the fringes of Turkish society. Turkey may be a deeply polarized country, but one thing Turks across all segments of society — Islamists, secular people, liberals, nationalists — seem to have come together on is that the United States was somehow wrapped up in the failed coup, either directly or simply because the man widely suspected to be the leader of the conspiracy, the Muslim cleric Fethullah Gulen, lives in self-exile in the United States.