US-Iran Relations Timeline

After Iran nationalized its oil industry in 1951, British and American intelligence services orchestrated a coup to overthrow Prime Minister Mohammad Mosaddegh and reinstall the pro-Western Shah. This covert operation, known as Operation Ajax, aimed to retain access to cheap oil and prevent communist expansion, but would fuel anti-American sentiment for decades.

The US signed an agreement to support Iran's use of nuclear energy for civilian purposes under President Eisenhower's "Atoms for Peace" program. A decade later, Americans provided Iran with a 5-megawatt nuclear research reactor and enriched uranium fuel.

Both the US and Iran were among the initial signatories of the Treaty on the Non-Proliferation of Nuclear Weapons, which entered into force in 1970. This bedrock agreement aimed to limit nuclear weapon spread while promoting peaceful atomic technologies.

President Nixon visited Tehran promising to sell the Shah any American arms Iran wanted, short of nuclear weapons, in exchange for protecting US interests in the Middle East. By the late 1970s, the Shah had purchased over $16 billion in arms, including F-14 fighter jets.

The Islamic Revolution led by Ayatollah Khomeini transformed Iran from a pro-West monarchy to an anti-West theocracy. When the US allowed the Shah entry for cancer treatment, Iranian students stormed the American embassy, taking 52 Americans hostage for 444 days.

After a failed rescue mission (Operation Eagle Claw) that killed eight US servicemen, President Carter cut diplomatic ties with Iran and suspended oil imports. Formal relations have never been restored. The Iran-Iraq War also began, with the US backing Iraq despite its use of chemical weapons.

After 444 days, US embassy hostages were released on January 19, minutes after Carter's term ended and Reagan was sworn in. Under the Algiers Accords, the US agreed to release frozen Iranian assets and not interfere in Iran politically or militarily.

The US designated Iran as a state sponsor of terrorism and imposed sanctions, including a weapons embargo. This followed the 1983 bombing of a multinational military barracks in Beirut that killed 241 American service members, believed to be perpetrated by Iranian-linked militants.

Despite the arms embargo, the Reagan administration secretly sold weapons to Iran to secure American hostages in Lebanon. Officials used proceeds to illegally fund Nicaraguan Contras, leading to the Iran-Contra scandal when exposed in 1986.

USS Vincennes shot down an Iranian passenger jet over the Strait of Hormuz, killing all 290 people aboard. The US said the plane was mistaken for a fighter jet and called the downing of Iran Air Flight 655 a "tragic and regrettable accident."

President Clinton imposed broader sanctions including an oil embargo and banned US trade and investment in Iran. The Iran and Libya Sanctions Act of 1996 penalized non-American companies investing in Iran's oil and gas sector.

President Bush described Iran as part of an "axis of evil" alongside North Korea and Iraq, claiming Iran "aggressively pursues weapons of mass destruction." This outraged Iran, which had been assisting the US against the Taliban. Secret nuclear sites at Natanz and Arak were revealed by Iranian dissidents.

Iran notified the IAEA it would suspend all uranium enrichment activity and agreed to stricter inspections. US intelligence later concluded that Iran had halted its nuclear weapons program (the Amad Plan) in 2003.

US, French, and UK leaders publicly revealed Iran's secret uranium-enrichment facility at Fordow, built deep into a mountain. Obama said the facility's "size and configuration" was "inconsistent with a peaceful program."

President Obama spoke by phone to Iranian President Hassan Rouhani - the first top-level contact in over 30 years. This led to the Joint Plan of Action in November, an initial nuclear deal that paved the way for broader negotiations.

The landmark Joint Comprehensive Plan of Action was signed. In exchange for sanctions relief, Iran pledged not to enrich uranium beyond 3.7% for 15 years and limited its stockpile to 300 kilograms. This represented a major diplomatic breakthrough.

President Trump unilaterally withdrew the US from the JCPOA, calling it the "worst deal ever." He restored sanctions and pursued "maximum pressure" to drive Iran's oil exports to zero. Iran began exceeding uranium enrichment limits, reaching 60% purity.

A US drone strike in Baghdad killed Iran's most powerful military commander, General Qassem Soleimani. Trump said he was "responsible for the death of millions." Iran retaliated by launching missiles at US military bases in Iraq.

The Biden administration began indirect talks in Vienna to restore the JCPOA but failed to reach agreement. In 2023, a prisoner exchange was arranged through intermediaries, with the US releasing $6 billion in frozen Iranian funds for humanitarian purposes.

After failed negotiations and an Israeli airstrike on Iran's nuclear program, the US joined Israel's offensive, striking key Iranian nuclear facilities including Fordow and Natanz with "bunker-buster" bombs. Iran retaliated by bombing a US base in Qatar, marking a dangerous escalation in the decades-long conflict.