The Yemen war has come to you in just two phone calls on a Thursday. Saudi Crown Prince Mohammed bin Salman called Donald Trump twice that day, urging him to send U.S. weapons to back a campaign against the Houthis. The president rejected the strikes, but agreed to a more limited kind of assistance: intelligence and targeting support provided by the approximately 200 non-combat US personnel already deployed in the kingdom. The exchange confirmed independently to Reuters, Axios, CBS News and CNBC by officials from both sides is the biggest sign yet a war Riyadh once said it could manage on its own is beyond the kingdom's means.

The backstory matters. The Houthis and Saudi warplanes had interrupted their four-year truce in July last year when they fired shots at each other over an Iranian passenger plane attempting to land in Sanaa. Saudi leaders at the time told Washington they had this and no need for American troops or bombs for Tehran, just more economic pressure. But that confidence has been lost, in a matter of weeks. Houthi forces have since advanced down the Red Sea coast, capturing the port city of Mokha and then the island of Zuqar and subsequently Perim Island and the final unclaimed islands within the Bab el-Mandeb strait itself. The internationally recognised Yemen government has confirmed that the group has now seized control of both sides of the chokepoint. The UN's migration agency estimates that at least 500 people have been killed in this latest wave of migration, as well as some 46,000 people displaced. This is in addition to a decade-long civil war.

The scheduling of the trip to Saudi Arabia by Admiral Brad Cooper, head of the U.S. Central Command, on the same day the crown prince was talking to Trump belays any notion this is a distraction for Washington. But the White House's public words have been toned down to avoid committing itself. The United States is “in continuous dialogue” with Riyadh and Yemen's government, but the mission is to “empower our regional partners to take the lead,” a top administration official told reporters, without revealing any specifics. The framing here is working hard. The US is already seven months in to the shooting war with Iran, which started way back in late February, and already caused one oil spike to $126 a barrel. While performing a quiet arms sale and sharing intelligence with the Saudi campaign against Iran's most battle-toughened proxy, Washington has no wish to formally continue the conflict in Yemen.

The economic factors are more telling than any diplomatic pronouncement. The port of Bab el-Mandeb handles between 10 and 12 percent of all global seaborne crude and about the same amount of container traffic between Asia and Europe. The loss of the Red Sea route will cut off the oil market of its main shortcuts and the Strait of Hormuz has already been closed by the US-Iran war. Brent already is above $105 a barrel this week and retail diesel fuel in the United States rose to a record $6 a gallon directly on trucking costs and food prices and not incidentally on Trump's approval ratings ahead of the upcoming midterm elections.

Xeneta freight analysts estimate that vessel transits through the strait have dropped by around 60 to 70 percent since the Houthis began to target shipping in late 2023, after increasing the frequency of attacks in recent days, resulting in a 46 percent decline in the last few days alone. The unobtrusive players here are insurers: even the threat of danger is enough to push the rate of shipping goods far enough to make the longer route around the Cape of Good Hope more attractive to the carriers twice as long as going through the Suez Canal, which is the shorter route.

The exposure for Saudi Arabia is not abstract but real. The crown of the world's biggest oil exporter, Riyadh, has been trying to divert shipments of crude oil via the Red Sea around the contested Hormuz straits, creating a pincer for the kingdom with both of its major maritime passages being tested. The reason is that Mohammed bin Salman must have been pretty serious about it as he decided to call Trump twice within a day instead of the regular contact. It also explains Saudi Arabia's public condemnation of the Houthis for threatening its ships and promising all necessary measures to prevent them from being attacked on the battlefield, which has not yet happened.

The impact is felt far beyond the Gulf. The blockade imposed by the Houthis on Saudi vessels since July is set to become more stringent, and India, which relies on the same shipping route for oil imports and exports to Europe, is preparing for higher shipping prices and rising crude costs. While a member of the Houthis' politburo assured this week that "freedom of navigation and international trade is safe and orderly," the fellow admitted that the Houthis' blockade of Saudi shipping is already a reality on the ground.