Seven decades of mistrust.

The story of US-Iran enmity begins paradoxically with a period of close cooperation. In the early Cold War, Washington saw Iran as a crucial bulwark against Soviet expansion and a key supplier of oil. The turning point came in 1953, when Prime Minister Mohammad Mossadegh moved to nationalise the Anglo-Iranian Oil Company, threatening Western energy interests.

In response, US and British intelligence orchestrated a covert operation to topple Mossadegh and restore full authority to Shah Mohammad Reza Pahlavi. The coup succeeded, and the Shah's regime became a pillar of US strategy in the Middle East, receiving weapons, economic aid and political backing. But for many Iranians, the 1953 intervention became a symbol of foreign meddling and stolen democracy, a grievance that would fuel anti-American sentiment for decades.

Throughout the 1960s and 1970s, the Shah modernised and militarised Iran with US support. American presidents hosted him at the White House, and Washington sold advanced aircraft and weapons systems to Tehran. Officially, the two governments were partners. Under the surface, however, discontent with the Shah's authoritarian rule, inequality and perceived cultural Westernisation was growing.

The 1980-1988 Iran-Iraq War pushed the US and Iran into direct but undeclared confrontation. Washington supported Saddam Hussein's Iraq as a counterweight to revolutionary Iran, providing intelligence and facilitating arms sales, while Iran sought to break Iraq's back through mass mobilisation and attacks on Gulf shipping.

In the mid-1980s, the Tanker War saw Iranian and Iraqi forces target oil tankers and merchant ships in the Gulf. The US reflagged Kuwaiti tankers and deployed naval forces to protect them. Clashes culminated in 1988 when the US Navy engaged Iranian vessels and accidentally shot down Iran Air Flight 655, killing 290 civilians, a trauma still cited in Iran as evidence of US hostility.

After the Cold War, the US fought two major wars next door in Iraq, in 1991 and 2003, further entrenching its military presence around Iran. From Tehran's perspective, US bases in the Gulf, the invasion of Iraq and talk of regime change after President George W. Bush called Iran part of an axis of evil confirmed fears that Washington ultimately sought to topple the Islamic Republic.

Beyond direct US-Iran contacts, much of the conflict plays out via proxies. Iran has built a network of allied militias and political movements across the Middle East, including Hezbollah in Lebanon, armed groups in Iraq and Syria, the Houthis in Yemen, and others, forming what it calls the Axis of Resistance.

From Washington's perspective, these groups are instruments of Iranian power projection, used to attack US troops, threaten allies such as Israel and Saudi Arabia, and destabilise states where the US has interests. American forces in Iraq and Syria have repeatedly come under rocket and drone fire from militias linked to Iran's Revolutionary Guard Corps, triggering US retaliatory strikes.

This proxy dimension makes de-escalation harder. Even when Washington and Tehran signal a desire to avoid full-scale war, local commanders, militias or third parties can launch attacks that drag both sides into new cycles of retaliation. The killing of Iranian General Qasem Soleimani by a US drone in Baghdad in 2020, and Iran's subsequent missile strikes on bases hosting US troops, illustrated how quickly the conflict can jump from covert operations to overt military exchanges.

For US policymakers, Iran represents a combination of risks: potential nuclear breakout, ballistic-missile expansion, support for groups that threaten US troops and allies, and the ability to disrupt oil flows and global markets. Iran's human-rights record and anti-Israel rhetoric add political pressure in Washington to stay tough.

For Iran's leaders, the United States is the pre-eminent external threat: a superpower that toppled governments in the region, invaded Iraq, overthrew Libya's regime and repeatedly talked of all options on the table for Iran itself. The memory of the 1953 coup and decades of sanctions reinforce the belief that Washington ultimately seeks to weaken or replace the Islamic Republic.

The US and Iran are locked in conflict not just because of one issue, but because of layered traumas and incompatible security narratives. 1953, 1979, the hostage crisis, the tanker war, the axis of evil, the nuclear standoff and proxy clashes have created a story on each side in which the other is the primary villain.

Diplomacy, from backchannel talks in Oman to the JCPOA, has shown that compromise is possible. But each time, domestic politics, regional shocks or trust deficits have pulled the two capitals back toward confrontation. As long as Washington fears a nuclear-armed, missile-rich Iran and Tehran fears regime-change pressure from a ring of US bases, the relationship is likely to remain a managed confrontation rather than a genuine peace.