The CIA isn't exactly known for its openness. But for a spy agency, it's been a gusher of information over the past week when it comes to old controversies.

The CIA has now acknowledged its role in the 1953 coup that deposed Iran's left-leaning Prime Minister Mohammad Mosaddegh. Few Iranians will be surprised. They have always believed Mosaddegh was ousted by U.S. and British interests, and those suspicions are a big part of Iran's mistrust of the West to this day.

The Iran revelation was not the only one.

Last week, as Mark reported over at our Two-Way blog, a newly declassified agency report not only mentioned Area 51, but it also placed it on a map. That's the desert facility in Nevada that has generated so many fanciful claims about the government secretly keeping the bodies of space aliens.

The agency also acknowledged — after years of denial — that it kept a file on Noam Chomsky, the MIT professor and political activist.

The revelations come amid a heated debate over secrecy surrounding intelligence gathering, especially related to the National Security Agency and its operations.

Intelligence agencies are known for their opacity. So it's significant when the CIA revealed its role in Mosaddegh's ouster in Iran — even though one U.S. secretary of state and one U.S. president have previously acknowledged America's hand in the coup, and more than a few books were written about it.

"It was always known, and that's what makes it so frustrating to have to wait so long to get this kind of acknowledgment from the U.S. government," Malcolm Byrne, deputy director and director of research at the National Security Archive, told us.

His organization received the newly declassified documents after a Freedom of Information Request.

CIA officials previously said most of the records related to the 1953 coup were either destroyed or lost in the 1960s because the "safes were too full."

A previous version of the material made public this week was released in 1981. But that version made no mention of the CIA's role in the coup.

The National Security Archive says on its website:

"The explicit reference to the CIA's role appears in a copy of an internal history, The Battle for Iran, dating from the mid-1970s. The agency released a heavily excised version of the account in 1981 in response to an ACLU lawsuit, but it blacked out all references to TPAJAX, the code name for the U.S.-led operation.

"Those references appear in the latest release. Additional CIA materials posted ... include working files from Kermit Roosevelt, the senior CIA officer on the ground in Iran during the coup. They provide new specifics as well as insights into the intelligence agency's actions before and after the operation."

But material was also withheld in the current release.

"Dozens of pages, just completely," Byrne said. "I don't know what the explanation is for that. But what I suspect is that some of it, at least, has to do with information that would reveal the role of our longtime ally, the British, who are by all accounts very skittish about having this information come out in an official way."

Britain hasn't acknowledged its role in the coup. Relations between Iran and Britain have been strained for decades.

This is not the first time a U.S. government agency has acknowledged its role in a coup.

In 1954, a CIA operation deposed Guatemala's left-leaning President Jacobo Arbenz Guzman. As The New York Times noted, the overthrow of Arbenz "squashed a 10-year effort to build a democratic state. Under a succession of military rulers who took power after the coup, Guatemala descended into three decades of a brutal civil war in which as many as 200,000 people died, many of them peasants killed by security forces."

The U.S. did not acknowledge its role in the coup until 2003 when the State Department documented "the U.S. government-approved role of the Central Intelligence Agency in the ouster of Arbenz."

The CIA has also previously said it knew of plans to overthrow Chilean President Salvador Allende in 1973, but denied direct involvement in that plot.

The release this week of the Iran papers raises questions about how documents are classified: Why is a section classified one year made public in another?

"The different agencies, and even the same agency sometimes, will declassify a document in different ways," Byrne says. "It's really up to the person who's doing it and what's going on at the time that they are reviewing it. It's a very subjective process."

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