One bridge or one power plant — that is the price Donald Trump set Wednesday for every Iranian attack on a ship in the Strait of Hormuz. Writing in capitals on social media, the US president said any missile, rocket, drone, or other device fired at a vessel would trigger an American strike on Iranian civil infrastructure. The announcement came hours after a fresh wave of US air strikes hit Iran overnight and air-defence systems lit up the skies above Tehran. Iran did not back down.

Foreign Minister Seyed Abbas Araghchi posted on X that any aggression against Iranian infrastructure "will compel a powerful and decisive response," framing the country's new posture as an eye-for-an-eye doctrine. Iran has already been striking back: it has targeted energy facilities and desalination plants — the source of drinking water for millions across the parched Gulf — in neighbouring countries. Tehran also launched a missile strike on a Jordanian city near the Israeli border, and alerts were issued in both Bahrain and Saudi Arabia within hours. The spiral is being felt far beyond the region.

The Strait of Hormuz, through which roughly one fifth of all the world's traded oil and gas flowed in peacetime, has been largely closed by Iranian attacks, driving fuel prices higher just as Americans approach midterm elections this autumn. Now Iran-backed Houthi rebels in Yemen are threatening Saudi shipping in the Red Sea, putting a second global trade chokepoint in their crosshairs. UN Secretary-General António Guterres condemned attacks on civilian infrastructure as "unacceptable" on Tuesday — a judgment that, under international law, applies to both sides.