Some of the briefs again reminded Mr. Bush that the attack timing was flexible, and that, despite any perceived delay, the planned assault was on track.

Yet, the White House failed to take significant action. Officials at the Counterterrorism Center of the C.I.A. grew apoplectic. On July 9, at a meeting of the counterterrorism group, one official suggested that the staff put in for a transfer so that somebody else would be responsible when the attack took place, two people who were there told me in interviews. The suggestion was batted down, they said, because there would be no time to train anyone else.

That same day in Chechnya, according to intelligence I reviewed, Ibn Al-Khattab, an extremist who was known for his brutality and his links to Al Qaeda, told his followers that there would soon be very big news. Within 48 hours, an intelligence official told me, that information was conveyed to the White House, providing more data supporting the C.I.A.’s warnings. Still, the alarm bells didn’t sound.