Leaders at the top of al Qaeda's hierarchy, the evidence shows, completed plans and obtained the materials required to manufacture two biological toxins - botulinum and salmonella - and the chemical poison cyanide.

Among all the upheavals of war with al Qaeda, the surest indicator of the historic stakes is the ongoing rotation of top U.S. government managers - scores at a time - into a bunker deep underground and far from Washington.

The gravest risks from al Qaeda combine its affinity for big targets and its announced desire for weapons of mass destruction.

Barton Gellman Quotes