Yemen is descending into a prolonged, uncontrollable war. The Saudi-led coalition fighting the country’s Houthi rebels has intensified its campaign since 60 of its soldiers were killed in a single attack on September 4th. Their bombs have rained on the capital, Sana’a. Qatar has sent 1,000 troops. Bahrain’s king has said his two sons will join the battle. Not that any of this guarantees success. Though their coalition has routed the Houthis from the port city of Aden, its progress has slowed around Taiz and the oil-rich province of Marib, scene of Friday’s attack. And the escalation puts paid to the latest attempt at negotiating peace. The Gulf states, where a generation of young, ambitious royals is coming to the fore, seem bent on annihilating the Houthis—whatever the cost. Nearly 5,000 people have died already. Many more deaths may follow.