How did the United States and Iran become such fierce enemies?

The relationship between the United States and Iran, marked by deep animosities and complex geopolitical dynamics, has its roots in historical events that have shaped the policies and perceptions of both nations toward each other.

U.S.-Iran relations have been marked by decades of tension, stemming from the 1953 CIA-backed coup, the 1979 Islamic Revolution, and ongoing disputes over Iran’s nuclear program, regional influence, and sanctions, leading to a complex and contentious dynamic.

Below, World History Edu analyzes these historical events as well as some of the major reasons why the two countries have been locked into a shadow war for decades:

The 1953 Coup and Its Aftermath

The first major event that sowed the seeds of enmity was the CIA-backed coup in 1953, which overthrew Iran’s democratically elected Prime Minister, Mohammad Mossadegh.

Mossadegh had nationalized the Iranian oil industry, which had previously been controlled by British interests under the Anglo-Iranian Oil Company.

The United States, motivated by Cold War dynamics and concerns over Soviet influence in Iran, as well as securing access to its oil, collaborated with the United Kingdom to orchestrate the coup.

The Shah of Iran, Mohammad Reza Pahlavi, was reinstalled with substantial power, which he used to modernize Iran but also to rule it with an increasingly autocratic hand. This event left a lasting scar on Iran’s collective memory, fostering a deep-seated suspicion and resentment towards the United States.

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The Shah’s Regime and Growing Discontent

Throughout the 1960s and 1970s, the Shah implemented a series of modernization and Westernization programs known as the White Revolution, which included land reforms, the expansion of women’s rights, and the rapid industrialization of the economy. Despite these reforms, the Shah’s regime was marked by autocracy, heavy reliance on the secret police (SAVAK), and suppression of political dissent, which alienated large segments of Iranian society, including religious groups, nationalists, and leftists.

The United States supported the Shah’s regime, providing military aid and economic assistance, further entrenching the perception among Iranians that the U.S. was complicit in the regime’s oppressive policies. This support was part of the broader U.S. strategy during the Cold War to counter Soviet influence in the Middle East and ensure access to oil resources.

The 1979 Islamic Revolution

The culmination of growing discontent against the Shah’s rule came in 1979 with the Islamic Revolution, led by Ayatollah Ruhollah Khomeini. The revolution was a complex social and political upheaval that resulted in the overthrow of the Shah and the establishment of the Islamic Republic of Iran.

The revolutionaries criticized the Shah’s close ties with the West, particularly the United States, and his secular policies that they felt undermined Islamic values.

The United States’ support for the Shah, especially its decision to allow him into the U.S. for medical treatment after he had been deposed, fueled suspicions that the U.S. might be plotting to reinstate him, similar to the 1953 coup. This led to one of the most defining moments in U.S.-Iran relations: the seizure of the U.S. Embassy in Tehran by Iranian students in November 1979, resulting in 52 American diplomats and citizens being held hostage for 444 days.

Undoubtedly, The hostage crisis was a traumatic event for both nations and led to the severance of diplomatic relations between the U.S. and Iran.

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The Iran-Iraq War and U.S. Involvement

The Iran-Iraq War (1980-1988) further complicated U.S.-Iran relations. Initially, the U.S. declared neutrality, but as the war progressed, it began supporting Iraq, led by Saddam Hussein, with intelligence, military equipment, and financial aid. This support was part of a broader strategy to contain the spread of Iran’s revolutionary ideology and prevent Iran from dominating the Persian Gulf region, which was vital for global oil supplies. The U.S. also engaged in direct military skirmishes with Iran in the Persian Gulf, further exacerbating tensions.

Post-War Relations and Escalating Tensions

In the decades following the Iran-Iraq War, several issues have fueled the animosity between Iran and the United States. The U.S. has accused Iran of sponsoring terrorism, pursuing nuclear weapons, and undermining peace and stability in the Middle East, particularly through its support for groups like Hezbollah in Lebanon and its involvement in the Syrian Civil War.

In response, the U.S. has imposed a series of economic sanctions on Iran, aimed at curtailing its nuclear program and limiting its regional influence.

The Iran Nuclear Deal

The nuclear issue, in particular, has been a focal point of contention. Iran’s nuclear program has raised international concerns about the potential for nuclear proliferation in the Middle East.

The 2015 Joint Comprehensive Plan of Action (JCPOA), commonly known as the Iran nuclear deal, was a landmark agreement between Iran and the P5+1 (the United States, the United Kingdom, France, Russia, China, plus Germany) that lifted economic sanctions on Iran in exchange for strict limitations on its nuclear program.

However, the U.S. withdrawal from the JCPOA under President Donald Trump in 2018, reinstating harsh sanctions, significantly heightened tensions and led to a series of confrontations in the Persian Gulf.

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Cultural and Ideological Factors

Beyond the geopolitical and strategic factors, cultural and ideological differences have also played a role in the U.S.-Iran enmity. The Islamic Republic’s ideological stance, which frames the U.S. as the “Great Satan,” and America’s portrayal of Iran as part of the “Axis of Evil,” have contributed to mutual demonization and a deep-seated mistrust between the two societies.

What does the future hold?

The history of U.S.-Iran relations is a testament to how past actions, geopolitical interests, ideological divides, and mutual perceptions can intertwine to create a prolonged state of hostility between two nations.

Efforts to break this cycle have been met with challenges, both internally within each country and externally from regional dynamics. The path to reconciliation, or at least a reduction in hostilities, requires addressing the deep-rooted grievances and fears that both nations harbor, along with a realistic appraisal of each other’s strategic interests and regional security dynamics.

The fierce enmity between the United States and Iran is the product of historical grievances, strategic confrontations, and ideological differences that have evolved over decades.

Frequently Asked Questions

These questions explore the key episodes and turning points that contributed to the transformation of Iran and the United States from allies into adversaries:

How were the U.S.-Iran relations like after World War II?

In the post-World War II era, Iran’s strategic significance to U.S. foreign policy became pronounced due to its proximity to the Soviet Union and its status as a key player in an oil-rich region. Initially, U.S.-Iran relations were amicable, especially after the 1941 Allied intervention which saw the replacement of Reza Shah Pahlavi with his son, Mohammad Reza Pahlavi. The younger Pahlavi aligned closely with American interests, fostering positive relations throughout his rule until 1979.

When did U.S.-Iran relations begin to sour?

The tenure of Prime Minister Mohammad Mosaddegh in 1951 marked a turning point. Mosaddegh’s nationalist and socialist reforms, particularly the nationalization of key industries, posed a direct challenge to Western economic interests, notably the Anglo-Iranian Oil Company—a British-controlled entity that dominated Iran’s oil sector. This move not only threatened Western access to Iranian oil but also served as a nationalist assertion of Iran’s sovereignty over its natural resources.

In 1951, Prime Minister Mohammad Mosaddegh’s socialist reforms and the nationalization of industries, especially oil, angered Western powers. This led to the U.S. and UK orchestrating a coup to remove him from power in Iran. Image: Mohammad Mosaddegh as Prime Minister of Iran.

How did the West respond to Iran’s nationalization of the oil industry?

The nationalization of the Anglo-Iranian Oil Company in 1952, ratified by Iran’s parliament, was a bold step that significantly impacted the British economy and led to a British-led embargo on Iranian oil. This embargo mirrored the kind of economic sanctions that would become a recurrent tool in Western policy towards Iran in the decades to follow. The economic strain from the embargo laid the groundwork for political instability, setting the stage for foreign intervention.

The U.S., alongside the UK, perceived Mosaddegh’s policies as a potential boon for Soviet expansion in the region. In response, they orchestrated a coup in 1953 that ousted Mosaddegh, an action that reasserted the Shah’s power and ensured Iran remained aligned with Western interests. This intervention, while securing short-term American and British objectives, sowed seeds of resentment and mistrust among Iranians towards the West, particularly the U.S., which would have profound implications for future relations.

What role did the CIA play?

Under President Harry S. Truman, the U.S. initially urged Britain to moderate its response to Iran’s nationalization of the oil industry under Prime Minister Mohammad Mosaddegh. However, Mosaddegh’s actions were seen a grave threat to the U.S. and its interest in the region.

In particular, the Central Intelligence Agency (CIA) perceived Mosaddegh as a destabilizing force in a strategically critical region, fearing Iran’s potential vulnerability to Communist influence and concerned about maintaining Western access to Middle Eastern oil.

In August 1953, the CIA, in collaboration with British intelligence, orchestrated a military coup that successfully ousted Mosaddegh, reinforcing the position of the pro-U.S. Shah, Mohammad Reza Pahlavi.

This intervention was not merely a geopolitical maneuver; it also underscored a contradiction in U.S. foreign policy. While modern U.S. politicians often critique Iran’s social and political conservatism and the intertwining of religion with politics, it was the U.S. itself that had previously undermined Mosaddegh, a secular democrat who represented a potential path toward a more liberal and democratic Iran.

Can the West be blamed for the Iranian Revolution in 1979?

The U.S.’s involvement in the coup has been cited as a critical factor leading to the 1979 Iranian Revolution’s vehemently anti-American sentiment. This historical interference has provided Iranian leaders with a potent narrative of Western meddling, which they have used to rally domestic support and deflect attention from internal issues. This narrative is difficult to counter, given the clear historical precedent of U.S. intervention in Iranian affairs.

What triggered the Iranian Hostage Crisis that lasted for 444 days?

The 1979 revolution marked a pivotal moment, with the Shah being deposed and Iran transforming from a monarchy into an Islamic Republic under Ayatollah Khomeini. The subsequent U.S. decision to allow the exiled Shah into America for medical treatment ignited fears among Iranians of another U.S.-backed coup, culminating in the U.S. Embassy takeover in Tehran and the hostage crisis, which severely strained U.S.-Iran relations.

The hostage crisis led President Jimmy Carter to sever diplomatic ties with Iran, a state of affairs that has persisted. The revolution and the ensuing crisis dramatically altered the U.S.-Iran trade dynamic and initiated a period of intense hostility, symbolized by anti-American protests in Iran.

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How was the U.S.-Iran relation in the 2000s?

Relations further deteriorated in the 2000s over allegations of Iran’s nuclear ambitions, leading to a stalemate that persisted until the 2015 nuclear deal, which temporarily eased tensions. However, the complex history of U.S.-Iran relations, marked by intervention, revolution, and mutual suspicion, continues to shape the interactions between these two nations, illustrating the enduring impact of historical actions on contemporary geopolitics.

How did the 2015 nuclear deal affect U.S.-Iran ties?

The 2015 nuclear deal, which lifted sanctions on Iran in exchange for limitations on its nuclear program, had appeared to signal a potential thawing of relations between Tehran and the international community, including the U.S.

However, underlying issues remained unresolved, as the deal did not address the broader spectrum of contentious issues between the U.S. and Iran, such as regional influence, support for proxy groups, and missile development. The lack of diplomatic relations since 1980, stemming from the Iranian Revolution and the subsequent U.S. Embassy hostage crisis, compounded these challenges.

The deep-seated historical grievances and strategic rivalries meant that the nuclear agreement, while significant, was perhaps too limited in scope to fundamentally transform U.S.-Iran relations, serving more as a temporary measure than a resolution to longstanding animosities.

Why did the animosity increase during the Trump Administration?

In May 2018, President Trump announced the U.S. withdrawal from the Joint Comprehensive Plan of Action (JCPOA), commonly known as the Iran nuclear deal, which had been signed in 2015 under President Obama. The deal had lifted economic sanctions on Iran in exchange for strict limits on its nuclear program. Trump’s withdrawal from the agreement, citing it as flawed and insufficient in addressing Iran’s missile program and regional behavior, led to the reinstatement of harsh U.S. sanctions on Iran.

Following the withdrawal from the JCPOA, the Trump Administration reinstated economic sanctions targeting key sectors of the Iranian economy, including oil exports, banking, and shipping. These sanctions significantly impacted Iran’s economy, contributing to a decline in its currency and increasing domestic discontent. The “maximum pressure” campaign aimed to compel Iran to renegotiate the nuclear deal on terms more favorable to the U.S. and to curb Iran’s regional influence.

On January 3, 2020, U.S. President Donald Trump’s decision to authorize the targeted killing of Qasem Soleimani, the influential commander of Iran’s Quds Force, escalated tensions in the Middle East, bringing the region to the precipice of conflict. This act was a significant provocation, given Soleimani’s role in extending Iran’s influence across the Middle East and his status within Iran.

The Trump Administration was particularly vocal about Iran’s regional activities, including its support for proxy groups in countries like Syria, Iraq, Lebanon, and Yemen. The U.S. viewed these actions as destabilizing and a threat to its interests and those of its allies in the region.

In the nutshell, the rhetoric from the Trump Administration, including hostile public statements and threats exchanged between Trump and Iranian leaders, further exacerbated tensions. The aggressive language contributed to a climate of mistrust and animosity, reducing the scope for diplomatic engagement.

In May 2018, Trump withdrew from the 2015 Iran nuclear deal. Image: Donald Trump, in 2017, serving as president of the US.

Timeline of U.S.-Iran relations

This timeline encapsulates the major milestones in U.S.-Iran relations, highlighting the complexities and shifts in their interactions over the past century.


  • Early 20th Century: Initial interactions; U.S. viewed as a neutral power.
  • 1941: Allied forces, including the Soviet Union and Britain, occupy Iran during World War II, replacing Reza Shah with his son, Mohammad Reza Pahlavi.


  • 1951: Mohammad Mosaddegh elected Prime Minister, nationalizes the oil industry.
  • 1953: U.S. and British intelligence agencies orchestrate a coup to overthrow Mosaddegh, reinstating Shah Mohammad Reza Pahlavi.


  • 1960s-1970s: Iran, under the Shah, becomes a close U.S. ally, receiving military and economic aid.
  • 1979: Islamic Revolution ousts the Shah; Ayatollah Khomeini comes to power. U.S. Embassy in Tehran is seized, and hostages are taken.


  • 1980-1988: Iran-Iraq War; U.S. supports Iraq while also secretly selling arms to Iran (Iran-Contra Affair).
  • 1988: U.S. Navy ship shoots down Iranian passenger plane, increasing tensions.


  • 1990s: Relations remain tense; U.S. imposes sanctions on Iran over its nuclear program and support for terrorism.


  • 2002: President George W. Bush labels Iran part of the “Axis of Evil.”
  • 2006-2010: International sanctions against Iran increase over its nuclear program.


  • 2015: Iran and P5+1 countries, including the U.S., sign the Joint Comprehensive Plan of Action (JCPOA) to limit Iran’s nuclear capabilities.
  • 2018: President Donald Trump withdraws the U.S. from the JCPOA, reinstating sanctions.


  • 2020: Tensions escalate with the U.S. assassination of Iranian General Qasem Soleimani.
  • 2021: Talks begin on the United States’ possible re-entry into the JCPOA under President Joe Biden, though challenges remain.

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