USA resident of Tehran washes "Yankee Go Home" graffiti from a wall in the capital city of Iran, Aug. 21, 1953. The new Premier Gen. Fazlollah Zahedi requested the clean-up after the coup d'etat which restored the Shah of Iran in power (AP Photo)

Tensions between the US and Iran hit a boiling point this month, but they’ve been simmering for decades.

Long before Washington killed Iranian commander Qasem Soleimani and Tehran responded with missile strikes on Iraqi bases housing US troops, the two countries have been at odds.

Points of contention have included control over Iran’s oil reserves, US political interference in Tehran, Iran’s desire for nuclear power and both countries’ growing influence in the Middle East.

It’s a long and complicated history, but let’s start in 1951 — when tensions between Iranians and foreign powers influencing the country first start to bubble.

 

Tension over British influence in Iran

Since the early 1900s, the British government has retained control over Iran’s oil reserves through the Anglo-Iranian Oil Company. By the time Mohammad Mossadegh is appointed Prime Minister, Iranians are tired of foreign involvement in their affairs, and calls for Iranians to regain control of their natural resources are growing louder.

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1953: CIA overthrows Iran’s democracy
CIA overthrows Iran’s democracy

The US helps stage a coup to overthrow Iran’s democratically elected prime minister, Mossadegh. He had moved to nationalize the country’s oil fields — a move the US and Great Britain saw as a serious blow, given their dependence on oil from the Middle East. After toppling Mossadegh, the US supports Iran’s monarch Mohammad Reza Pahlavi to rule as Shah of Iran. Iranians resent the foreign interference, fueling anti-American sentiment in the country for decades to come.

1957: Nuclear cooperation

The US signs a civil nuclear cooperation agreement with Iran. The agreement provides Iran with technology and resources that eventually become the foundation for its controversial nuclear program, which it begins developing in the 1970s with support from the US.

1979: The Iranian Revolution

The Iranian Revolution

Millions of Iranians take to the streetsin protest of the Shah’s regime, which they view as corrupt and illegitimate. Secular protesters oppose his authoritarianism, while Islamist protesters oppose his modernization agenda. On January 16, the Shah flees the country. On February 1, Ayatollah Khomeini, an Islamic scholar who had been arrested and deported by the Shah in 1964, returns from exile and becomes the supreme leader of the Islamic Republic

Iran Hostage Crisis

Iran Hostage Crisis

Iranian students storm the US embassy in Tehran and take dozens of Americans hostage. They demand the Shah, who had been admitted into the US for cancer treatment, be extradited to Iran to stand trial for “crimes against the Iranian people.” After 444 days, Iran releases the hostages in exchange for state assets being unfrozen —  minutes after President Ronald Reagan is sworn into office. During the crisis, the US cuts all diplomatic ties with Iran. Formal diplomatic relations have never been restored. The Shah dies in July 1980 in Cairo.

1980: Iran-Iraq War begins

Iran-Iraq War begins

The bad blood between the two countries is only made worse when the US backs Iraq in its invasion of neighboring Iran, prompting an eight year regional war. Qasem Soleimani, who has joined the elite Iran Revolutionary Guard Corps by this time, fights on the frontlines of this war.

1984: US declares Iran a sponsor of terrorism

US declares Iran a sponsor of terrorism

Under Reagan’s administration, the US declares the Islamic Republic a “state sponsor of terrorism.” Decades later, this designation by the US still stands.

1986: Iran-Contra Affair

Iran-Contra Affair

While the US is backing Iraq in its war with Iran, President Reagan’s administration covertly begins looking into ways to improve its relationship with Iran. The press reveals that despite an embargo on selling weapons to Iran, Reagan approved a high-profit sale in hopes that it will yield the return of Americans held hostage in Lebanon by Hezbollah, a militia with close ties to Iran.

1988: US shoots down an Iranian plane

US shoots down an Iranian plane

While American and Iranian ships are exchanging fire in the Persian Gulf, the US mistakes a civilian airliner for a fighter jet and shoots down Iran Air Flight 655. All 290 passengers and crew members on board are killed. Though the US says the attack is an accident, Iranians see it as intentional.

1997: Soleimani appointed head of the Quds Force

Soleimani appointed head of the Quds Force

Qasem Soleimani, who has been rising through the ranks of the Iran Revolutionary Guard Corps, is appointed chief commander of the Quds Force, an elite special forces unit that handles Iran’s overseas operations. He is instrumental in spreading Iran’s influence in the Middle East, and soon becomes one of the country’s most powerful leaders.

2002: George Bush declares Iran part of an ‘Axis of Evil’

George Bush declares Iran part of an ‘Axis of Evil’

After the 9/11 attacks, Iran quietly helps the US in its war against the Taliban, a mutual enemy of both countries. But in a State of the Union address, President George Bush refers to Iran, along with Iraq and North Korea, as part of an “Axis of Evil.” The speech incites anger in Iran.

Iran nuclear threat

Iran nuclear threat

As the US voices concerns that Iran is attempting to develop nuclear weapons, inspectors from the International Atomic Energy Agency announce they’ve found traces of highly-enriched uranium at a nuclear plant in Iran. Tehran agrees to suspend production of enriched uranium and allow stricter inspections of its nuclear sites, but this is short-lived. President Mahmoud Ahmadinejad would come into power a few years later and restart Iran’s production of enriched uranium, prompting years of international sanctions against the country.

2013: Iran nuclear deal is signed

Iran nuclear deal is signed

After years of negotiations with President Barack Obama’s administration, six nations and Tehran reach a landmark agreement that slows Iran’s nuclear development program in exchange for lifting some sanctions that caused the country’s economy to stagnate. It’s a huge breakthrough for the US and Iran, which have long been at odds.

2017: Trump takes office
Trump takes office

A week after his inauguration, President Donald Trump signs an executive order banning nationals from seven Muslim-majority nations, including Iran, from entering the US for 90 days. Iran calls the ban “an obvious insult to the Islamic world” and responds by conducting a ballistic missile test. The back-and-forth marks a sudden escalation in tensions between the two countries, raising concerns about the future of the Iran nuclear deal.

2018: May: Trump quits the Iran nuclear deal

May: Trump quits the Iran nuclear deal

Trump fulfills a campaign promise and announces he is withdrawing the US from the Iran nuclear deal, which he viewed as “one-sided.” He also says he will place new sanctions on the regime. Critics warn the move could lead Iran to restart its atomic program and set the stage for more conflict in the Middle East.

2019: April: US labels IRGC a terrorist organization

April: US labels IRGC a terrorist organization

President Trump announces that the US will formally designate the Iran Revolutionary Guard Corps, Tehran’s most powerful military institution, as a foreign terrorist organization. The move is unprecedented, marking the first time that the US designated a part of another government as a terror group. Iran responds by declaring the US a “state sponsor of terrorism.”

June: Iran blamed for attacks in the Gulf

June: Iran blamed for attacks in the Gulf

Tensions further escalate after attacks on oil tankers in the Persian Gulf and oil facilities in Saudi Arabia, as well as the downing of a US drone, which Washington and its allies blame on Iran. American officials repeatedly stress that threats to the freedom of navigation in the Gulf and the oil trade are unacceptable, but the Trump administration takes no action.

June: Iran reduces commitments to nuclear deal

June: Iran reduces commitments to nuclear deal

After the US imposes several rounds of sanctions on Iran that were originally lifted under the Iran nuclear deal, Iran announces it will ramp up enrichment of low-grade uranium. This breaks the stockpile limit it agreed to in 2015, and brings the country one step closer to being able to build a nuclear bomb.

December: US strikes facilities in Iraq and Syria

December: US strikes facilities in Iraq and Syria

US forces conduct airstrikes on facilities in Iraq and Syria, which the Pentagon claims are linked to pro-Iranian militias responsible for attacking US service personnel in Iraq. At least 25 people are killed, an Iran-backed militia says. Days later, hundreds of pro-Iranian demonstrators attempt to storm the US embassy in Baghdad, scaling the walls and forcing the gates open, in protest of the US airstrikes.

2020: January: US kills Soleimani, and Iran responds

January: US kills Soleimani, and Iran responds

Sabah Arar/Getty Images

Trump says he ordered an airstrike in Iraq to kill Iran’s top general, Qasem Soleimani — a move that previous US presidents had considered far too provocative. Thousands of people flood the streets of Iran to mourn him. Iran is furious and vows retaliation, ultimately firing missiles at Iraqi bases that house American troops a few days later. No lives are lost, and Trump responds by promising more sanctions.

As tensions rise, Iran mistakenly shoots down a Ukrainian passenger jet, attributing it to a fear of US aggression. All 176 people on board are killed.

Trump’s decision to respond diplomatically to Iran’s missile attack and not militarily signals that tensions may cool off — at least for now.

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