The Iran war is escalating again after peace talks collapsed, and the worst-case ending is not a nuclear bomb but the destruction of the Gulf's water plants — which would be catastrophic for tens of millions of people.

• Gulf countries drink water made from seawater: Qatar and Bahrain get all of it that way, Kuwait and Oman almost all, the UAE most, Saudi Arabia half.
• These plants are big, open, easy to break, and sit close to Iran's coast, with only a few days of backup water behind them.
• Both sides have already hit each other's plants — Iran struck one in Kuwait, the US struck one on Iran's coast — so the threat is live, not theoretical.
• A full attack could leave tens of millions of people days from running out of drinking water, needing an evacuation ten times bigger than anything ever attempted.
• Iran's real leverage would be the Gulf itself: it controls who sails through, so it could hold a rescue operation hostage.

Outlook: Both sides are climbing the escalation ladder with no deal in sight, so expect more tit-for-tat strikes near water and energy infrastructure before either backs down.