A History of US-Iran Relations: From 1953 to Today

Few bilateral relationships have shaped the modern Middle East as deeply as the one between Washington and Tehran. The history of US-Iran relations runs from close Cold War partnership to decades of open hostility, with a covert coup, a hostage crisis, and a contested nuclear program marking the major turning points. This is a factual walk through those events, drawn from reputable historical and news sources.

The 1953 Coup and Its Long Shadow

The relationship’s modern friction traces back to August 1953. According to Encyclopaedia Britannica and the National Security Archive, Iran’s parliament had voted in 1951 to nationalize the country’s oil industry under Prime Minister Mohammad Mosaddegh, a move that threatened British interests held through the Anglo-Iranian Oil Company, now part of BP.

Britain and the United States responded with a covert operation. The CIA called it TP-AJAX, or Operation Ajax, while British intelligence used the name Operation Boot. On 19 August 1953, Mosaddegh was removed from power and Mohammad Reza Shah Pahlavi was restored as Iran’s ruler. Britannica notes the operation was led on the American side by CIA officer Kermit Roosevelt Jr., a grandson of President Theodore Roosevelt. In 2013 the US government formally acknowledged its role by declassifying a large set of documents, the National Security Archive reported.

Historians widely view the coup as a root cause of later Iranian resentment toward Washington. It entrenched the Shah’s increasingly autocratic rule and tied his throne closely to American support, a perception that resurfaced powerfully during the 1979 revolution.

The Pahlavi Era: A Close Partnership

For roughly a quarter century after 1953, Iran was one of America’s closest allies in the region. The Shah modernized the economy and military with extensive US backing, and Iran served as a key Cold War partner bordering the Soviet Union. Washington supplied advanced weaponry and saw Tehran as a pillar of regional stability.

That partnership had costs at home. The Shah’s security services suppressed political opposition, and discontent grew across religious, nationalist, and leftist groups. By the late 1970s, mass protests had spread across Iran. The Shah left the country in January 1979, and the monarchy collapsed.

The 1979 Revolution and the Hostage Crisis

The Iranian Revolution brought Ayatollah Ruhollah Khomeini to power and established the Islamic Republic. Relations with the United States deteriorated quickly. The breaking point came on 4 November 1979.

According to the US State Department’s Office of the Historian and the National Archives, militant students stormed the US Embassy in Tehran and took American personnel hostage. They were angered that the Carter administration had admitted the ousted Shah to the United States for cancer treatment. Sixty-six Americans were initially seized, and 52 were held for 444 days. The National Archives records that the crisis ended on 20 January 1981, the day Ronald Reagan was inaugurated, when the hostages were released. A US-brokered agreement also freed billions of dollars in frozen Iranian assets.

The two countries severed diplomatic ties in 1980, and they have remained broken ever since. Switzerland has long served as the protecting power representing US interests in Iran.

Key Timeline of US-Iran Relations

1953 Operation Ajax removes Prime Minister Mosaddegh and restores the Shah.
1953 to 1979 Iran serves as a close US ally under the Pahlavi monarchy.
1979 The Iranian Revolution topples the Shah and creates the Islamic Republic.
1979 to 1981 The Tehran embassy hostage crisis lasts 444 days.
1980 The United States and Iran cut diplomatic relations.
2015 The JCPOA nuclear agreement is concluded.
2018 The United States withdraws from the JCPOA.
2020 A US drone strike kills General Qassem Soleimani.
2025 A 12-day Israel-Iran war draws in direct US strikes, followed by a ceasefire.

The Nuclear Deal: Diplomacy and Withdrawal

The next major chapter centered on Iran’s nuclear program. In July 2015, Iran reached the Joint Comprehensive Plan of Action with China, the European Union, France, Germany, Russia, the United Kingdom, and the United States. The Council on Foreign Relations summarizes the deal as limiting Iran’s nuclear activities in exchange for relief from sanctions. The agreement reduced Iran’s uranium enrichment capacity and required it to dilute or sell most of its enriched uranium stockpile, with verification by the International Atomic Energy Agency.

On 8 May 2018, the first Trump administration announced the United States would withdraw from the agreement, NPR reported. President Trump described the deal as flawed, arguing it failed to address Iran’s missile program and regional activities. The IAEA had reported that Iran was complying with the JCPOA at the time of the US withdrawal. After Washington reimposed sanctions, Iran gradually expanded its nuclear activities beyond the deal’s limits.

From the Soleimani Strike to the 2025 War

Tensions turned to direct confrontation in early 2020. On 3 January 2020, a US drone strike ordered by President Trump killed General Qassem Soleimani near Baghdad International Airport. Soleimani commanded the Quds Force of Iran’s Islamic Revolutionary Guard Corps and was widely regarded as one of Iran’s most powerful figures. The Pentagon said the strike was meant to disrupt attacks being planned against US personnel. Iran promised retaliation and launched missiles at bases in Iraq housing American troops days later.

The relationship entered another dangerous phase in 2025. According to PBS NewsHour and the Council on Foreign Relations, the United States and Iran began a new round of nuclear negotiations in April 2025 after an exchange of letters between President Trump and Supreme Leader Ali Khamenei. The talks stalled over US demands that Iran end uranium enrichment entirely, which Tehran rejected. Israel launched strikes on Iranian nuclear and military sites on 13 June 2025, beginning a 12-day conflict. The United States struck three Iranian nuclear sites on 22 June, Iran targeted a US base in Qatar on 23 June, and a ceasefire was announced on 24 June. As of mid-2026, the standoff over enrichment and IAEA inspections remained unresolved.

Frequently Asked Questions

Why did the United States and Iran break off diplomatic relations?

The two countries severed formal ties in 1980 following the seizure of the US Embassy in Tehran and the 444-day hostage crisis that began in November 1979. Diplomatic relations have not been restored, and Switzerland represents US interests in Iran.

What was the 1953 coup in Iran?

It was a covert operation by US and British intelligence, known as Operation Ajax, that removed Prime Minister Mohammad Mosaddegh in August 1953 and restored the Shah. The dispute centered on Iran’s nationalization of its oil industry. The US government formally acknowledged its role in 2013.

Is the 2015 nuclear deal still in effect?

The United States withdrew from the JCPOA in 2018 and reimposed sanctions. Iran later exceeded the deal’s limits on enrichment. Subsequent talks, including negotiations in 2025, did not produce a new agreement, and the nuclear question remains a central source of dispute.

Conclusion

The arc from 1953 to today shows a relationship that moved from alliance to estrangement and, at times, to open conflict. The coup, the revolution, the hostage crisis, and the nuclear dispute each left lasting marks on how Washington and Tehran view one another. Understanding these events helps explain why a durable settlement has remained out of reach for more than four decades.