Authored by Bethany Allen-Ebrahimian via ForeignPolicy.com,

Declassified documents released last week shed light on the Central Intelligence Agency’s central role in the 1953 coup that brought down Iranian Prime Minister Muhammad Mossadegh, fueling a surge of nationalism which culminated in the 1979 Iranian Revolution and poisoning U.S.-Iran relations into the 21st century.

The approximately 1,000 pages of documents also reveal for the first time the details of how the CIA attempted to call off the failing coup — only to be salvaged at the last minute by an insubordinate spy on the ground.

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 Great Britain 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. General Fazlollah Zahedi, a top conspirator, went into hiding, and the shah fled the country. 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 August 18, 1953. “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. “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 known. 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 a 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.) Operation Ajax has long been a bogeyman for conservatives in Iran — but also for liberals. The coup fanned the flames of anti-Western sentiment, which reached a crescendo in 1979 with the U.S. hostage crisis, the final overthrow of the shah, and the creation of the Islamic Republic to counter the “Great Satan.” The coup alienated liberals in Iran as well. Mossadegh is widely considered to be the closest thing Iran has ever had to a democratic leader. He openly championed democratic values and hoped to establish a democracy in Iran. The elected parliament selected him as prime minister, a position he used to reduce the power of the shah, thus bringing Iran closer in line with the political traditions that had developed in Europe. But any further democratic development was stymied on August 19. The U.S government long denied involvement in the coup. The State Department first released coup-related documents in 1989, but edited out any reference to CIA involvement. Public outrage coaxed a government promise to release a more complete edition, and some material came out in 2013. Two years later, the full installment of declassified material was scheduled — but might have interfered with Iran nuclear talks and were delayed again, Byrne said. They were finally released last week, though numerous original CIA telegrams from that period are known to have disappeared or been destroyed long ago.