64 Years Later, CIA Finally Releases Details of Iranian Coup

On August 19, 1953, the democratically elected Prime Minister of Iran Mohammad Mosaddegh was overthrown in a coup orchestrated by the United Kingdom and the United States.
An excerpt from an older article:

"Known as Operation Ajax, the CIA plot was ultimately about oil. Western firms had for decades controlled the region’s oil wealth, whether Arabian-American Oil Company in Saudi Arabia, or the Anglo-Iranian Oil Company in Iran. When the U.S. firm in Saudi Arabia bowed to pressure in late 1950 and agreed to share oil revenues evenly with Riyadh, the British concession in Iran came under intense pressure to follow suit. But London adamantly refused.

So in early 1951, amid great popular acclaim, Mossadegh nationalized Iran’s oil industry. A fuming United Kingdom began conspiring with U.S. intelligence services to overthrow Mossadegh and restore the monarchy under the shah. (Though some in the U.S. State Department, the newly released cables show, blamed British intransigence for the tensions and sought to work with Mossadegh.)

The coup attempt began on August 15 but was swiftly thwarted. Mossadegh made dozens of arrests. Gen. Fazlollah Zahedi, a top conspirator, went into hiding, and the shah fled the country.

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The CIA, believing the coup to have failed, called it off.

“Operation has been tried and failed and we should not participate in any operation against Mossadegh which could be traced back to US,” CIA headquarters wrote to its station chief in Iran in a newly declassified cable sent on Aug. 18, 1953. “Operations against Mossadegh should be discontinued.”

“Operations against Mossadegh should be discontinued.”
That is the cable which Kermit Roosevelt, top CIA officer in Iran, purportedly and famously ignored, according to Malcolm Byrne, who directs the U.S.-Iran Relations Project at the National Security Archive at George Washington University.

At least “one guy was in the room with Kermit Roosevelt when he got this cable,” Byrne told Foreign Policy. “[Roosevelt] said no — we’re not done here.” It was already known that Roosevelt had not carried out an order from Langley to cease and desist. But the cable itself and its contents were not previously published.

The consequences of his decision were momentous. The next day, on August 19, 1953, with the aid of “rented” crowds widely believed to have been arranged with CIA assistance, the coup succeeded. Iran’s nationalist hero was jailed, the monarchy restored under the Western-friendly shah, and Anglo-Iranian oil — renamed British Petroleum — tried to get its fields back. (But didn’t really: Despite the coup, nationalist pushback against a return to foreign control of oil was too much, leaving BP and other majors to share Iran’s oil wealth with Tehran.)"