Why the US still fears a full-scale war with Iran

The spectre of a US–Iran war has long hovered over the Middle East, occasionally erupting in tanker attacks, assassinations, dramatic standoffs in the Strait of Hormuz or covert sabotage. In June 2025, that spectre edged uncomfortably close to reality, before retreating behind the blurry lines of a ceasefire.

It’s an uneasy truce, brokered under intense pressure from Washington. Masoud Pezeshkian, the Iranian president, claimed a “historic victory”, while Israeli defence minister Katz said Israel “will respect the ceasefire — as long as the other side does”.

Meanwhile, Trump faced a fierce backlash back home. While the Democrat-led push to impeach him for ordering the airstrike on Iran without Congressional approval failed, the political spectacle underscores how divided the US is over risking a war that could spiral into the region’s most dangerous conflict in a generation.

Why does Washington, despite its unrivalled military might, recoil from taking this confrontation to ‘the logical conclusion’ — a regime change or total defeat of Iran’s military capability?

The answer lies in a tangled history spanning 70 years and an enduring lesson: Iran has never been an easy enemy to conquer or control, and the cost of trying to do so has always been judged too high.

In 1953, when the CIA and MI6 orchestrated the overthrow of democratically elected prime minister Mohammad Mosaddegh — who wanted to nationalise the Iranian oil industry and was feared to be pulling towards the Soviet Union — to restore the Shah to power, Washington planted the seeds of deep Iranian suspicion and resentment.

That resentment exploded in late 1979 when students stormed the US embassy in Tehran and kept 52 Americans hostage for 444 days.

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President Jimmy Carter, already weakened by the Shah’s fall, watched his presidency disintegrate under the weight of the crisis and a failed rescue mission that left helicopters burning in the Iranian desert.

This episode left a scar on America’s foreign policy establishment, which has been wary ever since of the use of brute force in the context of Iran. US presidents have threatened, sanctioned, bombed by proxy but rarely dared a full-scale invasion.

George W. Bush, who was the US president during and after 9/11, had famously labelled Iran a part of the ‘Axis of Evil’. His administration toppled regimes in Afghanistan and Iraq with breathtaking speed. Many hawks in his circle believed Tehran would be next.

But the insurgency in Iraq had already claimed thousands of American lives and cost billions of dollars, and the same advisors warned that a war with Iran — a country three times the size of Iraq, crisscrossed by mountains, capable of mobilising not just its own forces but a web of loyal militias from Lebanon to Yemen — would be far worse.

This sobering reality only grew clearer in the Obama years. Faced with intelligence reports that Iran was advancing its nuclear enrichment capabilities, Barack Obama chose the path of diplomacy instead of bombing. His critics called the Iran nuclear deal naïve, but for Obama, the alternative was a military operation, which might have set back Iran’s programme but couldn’t possibly destroy it, and almost certainly would have forced America into a war involving ground troops.

Trump, during his first term, took the opposite approach. He tore up the nuclear agreement, doubled down on ‘maximum pressure’ sanctions and ordered audacious strikes, including the 2020 assassination of Qassem Soleimani, Iran’s most powerful general. Yet even Trump, faced with Iran’s retaliatory missile barrage that injured dozens of US troops, stopped short of launching a sustained bombing campaign or committing to a ground invasion.

This time round, Trump edged closer to a direct conflict, yet the same caution reigns once again. American airpower bombed Iranian nuclear sites, struck Iranian command nodes and proxy bases to back Israel and deter a broader missile war in the Gulf. But the US still shunned a massive ground commitment that could ignite an oil crisis and plunge the fragile global economy into recession.

After Iran launched missile attacks on the US military base in Qatar, Trump’s unusual public “thanks” to Iran for providing advance warning signalled what both sides understood: neither truly wanted to open the gates of hell.

Iran, on its part, has demonstrated again why it is so difficult to confront decisively, given its geography, nationalism and the asymmetric arsenal of proxies.

Its Revolutionary Guard Corps cannot match America’s conventional firepower — but can bleed it slowly through militias in Lebanon, Yemen, Iraq, Syria and beyond. A full-scale war risks ensnaring Gulf monarchies, closing the Strait of Hormuz, and sending oil prices soaring.

The nuclear question remains the ultimate nightmare. Even after the strikes on three suspected nuclear sites, one can safely assume Iran’s programme has not been destroyed for good. Tehran could rebuild deeper underground or make a dash for a bomb — the scenario Washington dreads.

For now, an uneasy ceasefire holds, as Iran signals its openness to ‘resolve issues’ with Washington and Israel pledges restraint if Iran does the same. The pattern is familiar: forceful blows and sabre-rattling, calibrated to stop short of a regime-toppling invasion.

Iran’s leaders play the game expertly: enough provocation to inflict pain and raise costs, but not enough to justify an invasion that America has learned painfully it does not want.

If history teaches anything about the US–Iran standoff, it is this: overthrowing regimes can be swift, but stabilising what follows drains generations.

From the Shah’s fall to the hostage crisis, from the insurgencies in Baghdad to today’s ceasefire, the pattern repeats. America can punish Iran — but will not find victory worth the price of conquest.

The recent airstrikes, missile attacks and sudden truce have breached lines once considered unthinkable. Yet inside the White House and the Pentagon, the same cold truth shapes every move towards a strike or ceasefire — a war with Iran might begin on America’s terms but it will not end on those terms. It will end with oil tankers burning, embassies being stormed, prices spiking and US troops slogging and perishing in terrain that has humbled empires for centuries.

Views are personal. ASHOK SWAIN is a professor of peace and conflict research at Uppsala University, Sweden. More of his writing may be read here

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