Shaken by a failed coup attempt, Turkey’s government and many of its citizens are desperate for someone to blame. Instead of undertaking a thorough investigation of the facts, though, they have accused the United States of complicity in the insurrection. This has ignited a new wave of anti-Americanism that, combined with a sweeping government crackdown against enemies real and imagined, poses a serious risk to NATO, relations with the United States and Turkey’s long-term stability.

The main culprit behind the July 15 coup, according to President Recep Tayyip Erdogan and other Turkish leaders, is Fethullah Gulen, a Muslim cleric who has lived in self-imposed exile in Pennsylvania since 1999 and has denied any involvement in the attempted overthrow. But the pro-government press, political leaders and ordinary citizens across all segments of society are also pointing fingers at Washington, which has denied any involvement.

When Gen. Joseph Votel, the top American commander in the Middle East, told a security conference last week of his concerns about the effect of the purge on Turkish officers, including some who worked with the Americans and are now jailed, Mr. Erdogan faulted him for taking “the side of the coup plotters.” On Tuesday, Mr. Erdogan kept at it, giving a speech in which he said that in standing by the putschists, the West supported “terrorism.”

Meanwhile, the pro-government newspaper Yeni Safak accused the C.I.A.; Gen. John Campbell of the Army, formerly a NATO commander in Afghanistan; and Henri Barkey, who runs the Middle East program at the Woodrow Wilson Center, of being behind the insurrection. The evidence against Mr. Barkey? When the coup erupted, he was on an island near Istanbul holding a workshop for academics. The paper called it a “secret meeting” and said he made several telephone calls, hardly a suspicious activity. It also ran a headline claiming the United States had tried to assassinate Mr. Erdogan that night.