In a moment of brazen hubris in the Oval Office last year, US President Donald Trump railed at Ukrainian President Volodymyr Zelensky. He accused Zelensky of not being thankful for US support in Ukraine’s existential struggle against invading Russian forces, and famously told him: “You don’t have the cards”.

Now, more than a year later, it is Trump who doesn’t have a winning hand in his standoff with Iran.

Iran may be no match for the United States militarily, but it’s been very successful in exerting what leverage it does have over the Strait of Hormuz. Trump can declare the strait open to commercial shipping as much as he wants, but he cannot make it so.

The US has resumed bombing Iran this week to try to wrest control of the strait from Iran, but Trump could go even further if he finds himself backed into a corner.

How Iran is wielding its leverage

Iran’s leverage over the strait comes down to playing a spoiling role – one of the key tactics in asymmetric warfare.

The longer it can keep the strait closed, the more pressure it places on the US and its partners in the Persian Gulf to end the war. Some 20% of the world’s oil and gas and large supplies of sulphur, ammonia, urea and helium transit through the narrow passageway every day.

And as evidenced by its actions over the last week, the Islamic Revolutionary Guard Corps (IRGC) can threaten commercial traffic with drones or missile strikes anytime it likes. Despite heavy US bombardments since the........

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