Soldiers and onlookers outside Mohammad Mosaddegh's damaged house in Tehran on August 19, 1953

What Happened on 28 Mordad? Iran’s 1953 Coup Explained

In Iran, 28 Mordad 1332 is shorthand for one of the most consequential days in the country’s modern history. The date corresponds to August 19, 1953, when Prime Minister Mohammad Mosaddegh was overthrown and General Fazlollah Zahedi took his place. The event strengthened Shah Mohammad Reza Pahlavi’s position and left a lasting wound in relations between Iran, the United States, and Britain.

The anniversary returns on August 19 every year, but the story is often compressed into competing slogans. One version treats it as an entirely foreign-made coup; another calls it a constitutional royal dismissal or a spontaneous Iranian uprising. Declassified records show something more complex: the CIA and British intelligence planned and supported Mosaddegh’s removal, while Iranian military officers, politicians, clerics, royalists, crowds, and Mosaddegh’s own opponents shaped what happened on the ground.

What does “28 Mordad” mean?

Mordad is the fifth month of Iran’s Solar Hijri calendar. The 28th day of Mordad in the year 1332 fell on August 19, 1953. In Persian, the event is commonly called کودتای ۲۸ مرداد—the “28 Mordad coup.” English sources spell the prime minister’s name in several ways, including Mosaddegh, Mossadegh, and Mosadeq; they all refer to Mohammad Mosaddegh.

The Foreign Relations of the United States retrospective volume, published by the U.S. State Department in 2017, organizes hundreds of declassified records around the planning and implementation of Operation TPAJAX, the American codename for the effort to remove Mosaddegh.

Why did the crisis begin with oil?

In 1951, Iran’s parliament nationalized the country’s oil industry, which had been dominated by the British-controlled Anglo-Iranian Oil Company. Mosaddegh became prime minister that spring and emerged as the leading defender of nationalization. To many Iranians, the issue was sovereignty: Iran should control a resource extracted from Iranian soil and receive a fairer share of its value.

Britain rejected the nationalization settlement, imposed economic pressure, and sought ways to remove Mosaddegh. The oil dispute sharply reduced Iranian petroleum exports and revenue. It also became entangled with the Cold War. U.S. officials increasingly feared that political and economic instability might create an opening for the Soviet Union or Iran’s communist Tudeh Party.

The Truman administration spent much of the crisis pursuing a negotiated oil agreement. The Eisenhower administration, which took office in January 1953, accepted covert action. The State Department’s official preface to the declassified record describes U.S. covert operations as culminating in the overthrow of the Mosaddegh government in August 1953.

Was Mosaddegh democratically elected?

Mosaddegh is often called Iran’s “democratically elected prime minister.” The phrase captures his parliamentary support and constitutional legitimacy, but it can be misunderstood as a modern direct nationwide election for prime minister. Under Iran’s 1906 constitutional system, the Majles nominated or approved a prime minister, and the shah formally appointed him. Mosaddegh rose through this constitutional-parliamentary process and commanded a powerful nationalist movement.

His conflict with the shah was therefore not simply “democracy versus monarchy” in a modern presidential system. It involved unresolved questions about who controlled the armed forces, how far royal authority extended, what emergency powers a prime minister could exercise, and whether the shah’s decree dismissing Mosaddegh was constitutionally valid. Those disputes became part of the coup plan itself.

What were Operation TPAJAX and Operation BOOT?

The CIA called its operation TPAJAX; the British effort is commonly associated with the codename BOOT. Plans included propaganda against Mosaddegh, efforts to persuade the shah to issue decrees dismissing him and appointing Zahedi, contacts with Iranian politicians and military officers, and attempts to build street and institutional support for a successor government.

An internal CIA history later stated that Mosaddegh’s overthrow was carried out under CIA direction as an act of U.S. foreign policy. The declassified history is available through the George Washington University National Security Archive. The State Department’s 2017 collection likewise includes an entire section titled “Planning and Implementation of Operation TPAJAX, March–August 1953.”

British interests were central because of the oil confrontation, but many British operational files have remained less accessible than the American record. That uneven archive is one reason historians can describe the broad Anglo-American role with confidence while still debating particular agents, payments, decisions, and local alliances.

The failed attempt of August 15–16

The operation did not succeed on its first try. Late on August 15, Colonel Nematollah Nassiri attempted to deliver a royal decree dismissing Mosaddegh. Forces loyal to the prime minister arrested him, and the planned military action unraveled. The shah left Iran, first for Baghdad and then Rome.

At that moment, the operation appeared defeated. A later CIA study described how the signed royal decrees changed the campaign’s strategy: organizers could present Zahedi as the shah’s lawful choice and Mosaddegh as defying royal authority. The National Security Archive’s discussion of the declassified study, “Zendebad, Shah!”, emphasizes that the August 19 outcome became a rapidly improvised political and psychological campaign rather than a simple replay of the failed military plan.

What happened on August 19?

On the morning of August 19, pro-shah crowds moved through Tehran. They were joined by police and military elements, and attacks targeted pro-Mosaddegh organizations, newspapers, government sites, and the offices of the Tudeh Party. Radio Tehran became a decisive prize because control of broadcasting could make Zahedi’s victory appear national and irreversible.

Fighting reached Mosaddegh’s residence, which was shelled and looted. Mosaddegh escaped over a wall but surrendered the following day. Zahedi emerged as prime minister, and the shah returned to Iran.

The crowds were not one uniform body. Some participants were mobilized through networks connected to the covert operation; others were royalists, military supporters, religious or political opponents of Mosaddegh, opportunists, or people responding to a fast-changing situation. The surviving documentary record supports a major CIA role without reducing every Iranian actor to a paid foreign agent. As the declassified CIA analysis itself acknowledges, internal forces and local decisions mattered—and their exact weight remains debated.

Was it a coup or a constitutional dismissal?

Supporters of the shah have sometimes argued that Mosaddegh was lawfully removed by royal decree and that August 19 was a popular uprising restoring constitutional order. Critics answer that a secretly organized foreign operation used those decrees as political cover to overthrow a government that retained constitutional and popular legitimacy.

“Coup” remains the standard term in most modern scholarship and in the U.S. government’s own retrospective documentary collection. The constitutional decrees are still important evidence, but they do not erase covert planning, propaganda, financing, military coordination, or the failed first attempt. A careful account can recognize the constitutional dispute without treating TPAJAX as imaginary.

What happened to Mosaddegh and the shah afterward?

Mosaddegh was tried by a military court, imprisoned for three years, and then confined to house arrest in Ahmadabad until his death in 1967. Zahedi’s government secured American support and reached a new oil arrangement. The shah’s authority grew substantially over the following decades, while political opposition faced increasing restrictions.

The coup did not instantly create every feature of Iran’s later monarchy, but it altered the political balance. It weakened a major parliamentary-nationalist movement, tied the shah more closely to Western backing, and provided opponents of the monarchy with a durable example of foreign intervention. When revolution came in 1979, memories of 1953 remained politically potent.

Why 28 Mordad still matters

The event continues to shape how many Iranians interpret foreign pressure, regime change, oil politics, and American intentions. It also complicates diaspora conversations. Some Iranians remember the Pahlavi period through modernization, secular public life, and national symbolism; others center political repression and the destruction of constitutional possibilities. Many hold elements of both views at once.

Remembering 28 Mordad responsibly means resisting a simple hero-and-villain script. Mosaddegh’s government had internal conflicts and made controversial decisions. The shah had a constitutional role, but foreign intelligence services helped transform a domestic power struggle. Iranian actors possessed agency, but the covert operation was real. The most reliable history holds those facts together.

Explore related Iranian history

For more context on the monarch whose position was strengthened after 1953, read Who Was Mohammad Reza Pahlavi? Iran’s Last Shah Explained. Readers interested in the era’s visual symbols can also explore the active Pahlavi Iran Flag with Lion and Sun and the Mohammad Reza Pahlavi T-Shirt. These objects reflect how Pahlavi imagery remains visible in Iranian memory and diaspora identity; linking them here is historical context, not a judgment on the coup.

Sources

Image credit: Soldiers and onlookers outside Mohammad Mosaddegh’s damaged residence in Tehran, August 19, 1953. Photograph by Stephen Langlie, USAF/MAAG. Held in the Stephen Langlie Collection, Middle East Centre Archive, St. Antony’s College, Oxford; public domain as a work created by a U.S. Air Force employee in the course of official duties.

Retour au blog