Behind the political scenery, and on the festering subject of Israel, relations between Riyadh and Washington had recently become unprecedentedly shaky. Crown Prince Abdullah had long fumed about America's apparent complacency over the plight of the Palestinians.

That spring he had pointedly declined an invitation to the White House. Three weeks before 9/11, enraged by television footage of an Israeli soldier putting his boot on the head of a Palestinian woman, he had snapped. Bandar, the crown prince's nephew, was told to deliver an uncompromising message to President Bush.

"I reject this extraordinary, un-American bias whereby the blood of an Israeli child is more expensive and holy than the blood of a Palestinian child . . . . A time comes when peoples and nations part . . . . Starting today, you go your way and we will go our way. From now on, we will protect our national interests, regardless of where America's interests lie in the region." There was more, much more, and it rocked the Bush administration. The president responded with a placatory letter that seemed to go far toward the Saudi position of endorsing the creation of a viable Palestinian state.

Then came the shattering events of Tuesday the 11th. In Riyadh within 24 hours-himself now in turn placatory-Abdullah pulled the lever that gave his nation its only real power, the economic sword it could draw or sheathe at will. He ordered that nine million barrels of oil be dispatched to the United States over the next two weeks. The certainty of supply had the effect, it is said, of averting what had otherwise been a possibility at that time-an oil shortage that would have pushed prices through the roof and caused, on top of the economic effects of the 9/11 calamity, a major financial crisis.

Into the mix, on Wednesday the 12th, came troubling news. In a phone call that night, a C.I.A. official told Ambassador Bandar that 15 of the hijackers had been Saudis. As Bandar recalled it, he felt the world collapsing around him. "That was a disaster," Crown Prince Abdullah's foreign-affairs adviser Adel al-Jubeir has said, "because bin Laden, at that moment, had made in the minds of Americans Saudi Arabia into an enemy.

Did Saudi Arabia Attack Us on 9/11?