Iranian Foreign Minister Mohammad Javad Zarif speaks to the media on April 22 in New York. (Frank Franklin II/Associated Press)

AT THE heart of the Obama administration’s diplomatic engagement with Iran is the notion that the regime is divided among hard-liners who foment its terrorism and regional aggression and more moderate forces who are open to cooperation with the West. The embodiment of the latter is said to be Foreign Minister Mohammad Javad Zarif, an English-speaking favorite of many Western journalists and, even more so, Secretary of State John F. Kerry.

However, if there really is a gulf between Mr. Zarif and the supposed hard-liners, he often does a good job of disguising it. During the 18-month imprisonment of The Post’s Jason Rezaian, for example, Mr. Zarif offered public support for the absurd and mendacious claim that Mr. Rezaian was guilty of espionage. The foreign minister suggested Mr. Rezaian had been taken “advantage” of by an “overzealous low-level operative” of the U.S. government.

More recently, Mr. Zarif was asked to explain why Iran is sponsoring a cartoon festival beginning this Saturday on the theme of the Holocaust. It’s the second time the regime has staged such a event; the first, a poisonous orgy of anti-Semitism, was held in 2006 under President Mahmoud Ahmadinejad — one of the “hard-liners,” according to Obama administration theory.

Mr. Zarif’s response to interviewer Robin Wright of the New Yorker was a form of denialism: He claimed the Rouhani administration had nothing to do with the exhibition. The sponsor is a nongovernmental organization “that is not controlled by the Iranian government,” he said. Moreover, he said, the organization had not needed government permission to stage the event. It was, he said, comparable to the activity in the United States of the Ku Klux Klan. “Is the government of the United States responsible for the fact the there are racially hateful organizations in the United States?” he demanded.

Naturally, it didn’t take long for this dissembling to be challenged. What was interesting is that some of the pushback came from Mr. Zarif’s own government. A spokesman for the Ministry of Culture and Islamic Guidance confirmed that the ministry supports the exhibition, along with other programs that “enlighten people about the Holocaust.” A festival official also reported that it was cooperating with the ministry.

The U.S. Holocaust Memorial Museum reports that one of the organizations staging the festival, the Owj Media and Cultural Institute, is funded by the Iranian Revolutionary Guard Corps; another, the Sarcheshmeh Cultural Complex, is backed by the Islamic Development Organization, whose budget is approved by the Iranian parliament. As for whether a public exhibition can be held in Tehran without official approval, we’ll believe that as soon as the first festival of liberal democracy takes place.

Mr. Zarif claimed that “people who have preached racial hatred and violence” would not be issued visas to attend the cartoon conference. We’ll soon see if that’s the case. In the meantime, it’s worth considering the response Ms. Wright got when she asked the foreign minister about President Obama’s recent reference to “the more reasonable forces in Iran.”

“That’s what I do not believe — that dividing Iran into ‘reasonable’ and ‘unreasonable’ forces is either correct, conducive, or anybody’s business,” said Mr. Zarif. “When the United States exercised that practice in the past, it didn’t produce results.”

On that, we’ll take Mr. Zarif at his word.