The 1953 Coup

On 19 August 1953, Iranian prime minister Mohammad Mosaddeq was overthrown and General Fazlollah Zahedi emerged as his replacement. The event is also known by its Iranian calendar date, 28 Mordad 1332. It followed the confrontation over oil nationalization and intensified conflict within Iranian politics. s1

Foreign involvement is documented rather than merely alleged. Declassified material identifies a covert operation involving the United States’ Central Intelligence Agency, or CIA, and British intelligence. The American operation carried the code name TPAJAX. A documentary collection published by the National Security Archive includes operational correspondence, propaganda material, and internal CIA histories acknowledging the agency’s participation. s2

Mosaddeq’s original coalition had fractured. Former allies disagreed with his appointments and request for emergency powers, while Zahedi and other opponents organized against him. Foreign planners sought cooperation from Shah Mohammad Reza Pahlavi, military officers, and political intermediaries. The shah signed decrees dismissing Mosaddeq and appointing Zahedi. s1

The records also show that intervention was neither perfectly coordinated nor certain to succeed. A later internal CIA history records doubts about the shah’s willingness to support the chosen replacement and about whether the army would act without his cooperation. National Security Archive editors emphasize the participation of Iranian actors alongside the intelligence agencies. Recognizing Iranian agency does not erase foreign intervention; it explains the political and military channels through which it operated. s3

The initial attempt unraveled on the night of 15 August, when Colonel Nematollah Nassiri, who delivered the dismissal decree, was arrested. The shah left Iran. Coup organizers then continued their efforts rather than abandoning the operation. s1

On 19 August, pro-Zahedi forces gained support from military units and seized important sites, including Radio Tehran. Fighting reached Mosaddeq’s residence; he escaped initially and surrendered the next day. He was subsequently imprisoned and then held under house arrest until his death in 1967. s1

The main phases of the August crisis

The diagram distinguishes the failed initial attempt from the later overthrow. It presents the principal sequence without assigning every participant or action to a single chain of command.

A particularly revealing record is a proposed public statement prepared before the overthrow. As described in the National Security Archive’s document guide, its language credited the Iranian people under the shah’s leadership, obscuring the covert role behind the anticipated outcome. Other documents concern propaganda and commendations for personnel supporting the operation. Such records help distinguish contemporary public explanations from private planning. s2

The archive remains incomplete. The National Security Archive reports that much internal CIA correspondence was destroyed in 1962, and released histories contain substantial omissions. Internal histories are also retrospective accounts produced by an institution involved in the event. They should be compared with other evidence rather than treated as an exhaustive or disinterested narrative. s3

The central evidentiary distinction is between establishing participation and measuring its precise causal weight. The surviving documents support the conclusion that foreign agencies helped plan and implement Mosaddeq’s removal. They do not make every detail of the operation transparent or reduce Iranian participants to instruments without their own aims. A careful account preserves both conclusions and identifies uncertainty at the level where it remains. s2s3