The first visit to Washington by Salman bin Abdul-Aziz Al Saud as the Saudi monarch comes as the kingdom faces multiple difficult challenges. The Sept. 4 summit will do little to address Saudi Arabia's deep problems, because they are impervious to an American solution.

Salman's top priority is to win the Saudi-led war in Yemen that Riyadh portrays as a decisive response to Iranian aggression and subversion. The king has been praised at home for developing the Salman Doctrine, which emphasizes self-reliance on security issues. The kingdom will henceforth aggressively and decisively defend its interests without depending on American leadership. The Saudis will lead coalitions of like-minded Sunni states to counter Iranian and other Shiite enemies. The doctrine is much more robust than the very cautious and risk-averse approaches characteristic of Salman's predecessors and a response to perceived American indecisiveness toward Iranian gains in Syria and Iraq.

The Saudi coalition has made significant advances after five months of engagement. The port of Aden and the city of Taiz have been captured from the Houthis and their ally, former President Ali Abdullah Saleh. Pro-Saudi Yemeni recruits are being organized into so-called Salman Decisiveness Brigades. Forces loyal to President Abed Rabbo Mansour Hadi have faced difficulties trying to stabilize the territory recovered from al-Qaeda, southern separatists and other militants. Law and order remain elusive, especially in Aden. Hadi continues to stay in Riyadh rather than return home. The Hadi forces rely heavily on Saudi air power and armor provided by the United Arab Emirates.

Hadi and the Saudis say they will seek to take Sanaa from the Houthis this fall, by far the most ambitious operation yet. The city has a population of 2 million. The United Nations reports the Yemeni civilian population is suffering catastrophic conditions, with little food, water or medical supplies. Combat in a major urban area could exacerbate the humanitarian situation drastically. The Saudis already face charges of war crimes and human rights abuses. The king will push for more US logistical and intelligence support for the war and turn a blind eye to its consequences.