Iran spent years and billions of dollars building up the network of allies and proxies that Iran called ‘the axis of resistance’ that included Hezbollah in Lebanon and Hamas in Gaza and the West Bank to threaten and deter Israel. The Israelis have hit it very hard and effectively since the Gaza war started with the Hamas attacks of 7 October 2023.

But Iran is now demonstrating that a geographical feature, the narrow Strait of Hormuz, can be an even more effective deterrent and threat than its ruinously expensive system of military alliances. Iran can enforce its control of the Strait with cheap drones that can be launched from hundreds of kilometres away in Iran’s mountainous interior.

Allies get killed. Geography stays the same. Short of capturing and occupying the cliffs on either side of the Strait, and big stretch of Iranian land beyond them, the US and Israel – and the rest of the world – are discovering that the Iranian regime will demand a big say in the reopening the Strait of Hormuz.

As the former deputy commander of NATO, General Sir Richard Shirreff observed on the BBC’s Today Programme, any war game working through the consequences of an attack on Iran would have shown that the Islamic Revolutionary Guard Corps would close the Strait of Hormuz.

That gets back to the importance of planning how to start a war, how to end it and how to deal with the day after. Donald Trump and his inner circle, flushed with the prospect of a quick and easy victory, seem to have skipped those steps.

The ‘axis of resistance’ also includes the Houthis in Yemen. On Friday they fired a barrage of missiles at Israel for the first time since this war started with the airstrikes on Iran on 28 February. If the Houthis resume their attacks on shipping in the Red Sea, Saudi Arabia would lose its western sea route for oil exports to Asia.

The Red Sea has its own choke point, the Bab al Mandab strait, as important for world trade as the Strait of Hormuz. If the Houthis decide to escalate by attacking shipping in Bab al Mandab and further south, as they did during the Gaza war, they would cut off the route from Asia to Europe through the Suez Canal.

That would create an even worse global economic emergency.