On 14 August Iran's foreign minister told the Gulf states that their critical infrastructure would be struck if Washington resumed large-scale operations. Three desalination plants have already been hit since March — one in Bahrain, one in Kuwait, and one on Iran's own Qeshm Island. Each time the damage was called limited and the supply held. Read the five replies to this week's threat side by side, and one of them is not reassurance. It is arithmetic
