The U.S. Department of State has blocked the publication of a long-awaited documentary history of U.S. covert action in Iran in the 1950s out of concern that its release could adversely affect ongoing negotiations over Iran’s nuclear program.

The controversial Iran history volume, part of the official Foreign Relations of the United States (FRUS) series, had been slated for release last summer. (“History of 1953 CIA Covert Action in Iran to be Published,” Secrecy News, April 16, 2014).

But senior State Department officials “decided to delay publication because of ongoing negotiations with Iran,” according to the minutes of a September 8, 2014 meeting of the Advisory Committee on Historical Diplomatic Documentation that were posted on the Department of State website this week.

Dr. Stephen P. Randolph, the Historian of the State Department, confirmed yesterday that the status of the Iran volume “remains as it was in September” and that no new publication date has been set. The subject was also discussed at an Advisory Committee meeting this week.

The suppression of this history has been a source of frustration for decades, at least since the Department published a notorious 1989 volume on U.S. policy towards Iran that made no mention of CIA covert action.

But the latest move is also an indirect affirmation of the enduring significance of the withheld records, which date back even further than the U.S. rupture with Cuba that is now on the mend.