It’s a gamble. And in war, gambles made with other people’s resources are always paid for by those who make them.

After more than a decade of war, the Houthis have achieved what a superpower-backed coalition spent ten years and tens of billions of dollars trying to prevent. They now sit astride the Bab al-Mandeb strait, one of the world’s critical maritime chokepoints, and they are once again raining missiles and drones on Saudi cities. And when Riyadh picked up the phone this week to ask Washington for help, the answer was no.