As US and Israeli jets descended to deliver the opening salvos of the war in Iran, Donald Trump’s back-of-the-envelope plan for regime change in Tehran was about to run into the reality of the largest US intervention in the Middle East since the start of the Iraq war in 2003.

That reality came quickly.

One hundred and seventy-five people were killed when a US Tomahawk missile slammed into a girls’ school, apparently because the Pentagon used outdated targeting data for the strike. Hundreds of air-defence missiles were expended as Iran’s initial missile counterattack was mostly parried – but one drone smashed into a makeshift command centre in Kuwait, killing six US troops and wounding dozens more.