For four decades, the threat to close the Strait of Hormuz was a match Iran never lit. Even during the Iran-Iraq war in the 1980s, when more than 400 vessels were attacked in the Gulf, Tehran showed restraint. It did not attempt to seal the strait even after the USS Vincennes mistakenly shot down an Iranian passenger plane in 1988, killing 290 people. That restraint has now ended.
US forces have struck hundreds of Iranian targets over three consecutive nights, including in the southern port city of Bandar Abbas, as President Donald Trump seeks to reassert control over the vital waterway. Trump has declared the US the “guardian” of the strait, revived a naval blockade of Iranian ports, and briefly demanded a 20% toll on all cargo passing through—a move his own secretary of state, Marco Rubio, had ruled out just two weeks earlier.
Iran has responded by striking two tankers in the strait, killing a crew member, and hitting US bases across the Gulf. Tehran’s decision to target commercial vessels represents a brazen attempt to frustrate the US and, by extension, the global economy. But the key question is why Iran has chosen to act now, when it has possessed the capacity to menace the strait for decades.
A Shift in Risk Perception
The answer lies not in material capability but in a psychological shift within Iran’s leadership. Political scientist Caitlin Talmadge argued in 2008 that closing the strait would be “the military equivalent of cutting off its nose to spite its face,” because it would undermine Iran’s own oil revenue and invite retaliation. That logic held through every round of escalation prior to 2026. In 2011, Iran’s vice-president at the time, Mohammad Reza Rahimi, threatened that “not a drop of oil will pass through the Strait of Hormuz” if Western sanctions went ahead, yet Tehran ultimately acquiesced.
Prospect theory offers a compelling explanation for the reversal. Decision-makers are less likely to accept risk when they perceive themselves in a position of gain, preferring the certainty of what they hold. But when leaders view their situation as one of loss, they become more willing to gamble to recover those losses. Iran’s new Supreme Leader, Mojtaba Khamenei, has framed the conflict in exactly these terms.
In a March 12 statement, two weeks after the assassination of his predecessor, Ali Khamenei, he declared: “The revenge we have in mind is not just because of the martyrdom of the illustrious leader of the revolution. Every member of the nation martyred by the enemy is a separate case that demands we seek revenge … the leverage of closing the Strait of Hormuz must definitely continue to be utilised.”
This narrative has been echoed beyond Tehran. In mid-April, Iranian cleric Hojjat al-Islam Jafar Rastakhiz, addressing the strait itself, stated: “For 47 years the criminal America has sanctioned us … the Strait of Hormuz, because of the atrocities of America, has been closed.” The regime has portrayed Iran as a state burdened by an accumulation of military, political, and symbolic losses that demand recovery. Ali Khamenei’s funeral, which drew mass processions across Iran, turned these losses into a public ritual, with mourners chanting: “Our word is one! Revenge! Revenge!”
This rhetoric reveals how the regime now narrates its own position. It has created the conditions under which greater risk acceptance becomes conceivable. For the US, there is an uncomfortable implication: Trump’s decision to commit to further strikes on Iran, while defending commercial vessels in the strait, may be subsidizing the psychological conditions that sustain Tehran’s risky behavior. Effective deterrence presumes an adversary weighing what it stands to lose. But against a regime that believes it has already lost, each strike simply deepens the deficit it is gambling to recover.
The fight is now being waged on ground that Tehran has defined. As Iran drags the US into a protracted conflict over the Strait of Hormuz, the region watches closely. For more on this dynamic, see our analysis of how Iran is defying Trump's wishes and the limits of US military force alone in securing the waterway.
