In fashioning this sensitive policy in the midst of an impeachment crisis that lasted into early 1999, Clinton's national security adviser, Samuel R. "Sandy" Berger, struggled to forge a consensus within the White House national security team. Among other things, he had to keep on board a skeptical Attorney General Janet Reno and her Justice Department colleagues, who were deeply invested in law enforcement approaches to terrorism, according to senior officials involved.

As the months passed, Clinton signed new memos in which the language, while still ambiguous, made the use of lethal force by the CIA's Afghan agents more likely, according to officials involved. At first the CIA was permitted to use lethal force only in the course of a legitimate attempt to make an arrest. Later the memos allowed for a pure lethal attack if an arrest was not possible. Still, the CIA was required to plan all its agent missions with an arrest in mind.

Some CIA managers chafed at the White House instructions. The CIA received "no written word nor verbal order to conduct a lethal action" against bin Laden before Sept. 11, one official involved recalled. "The objective was to render this guy to law enforcement." In these operations, the CIA had to recruit agents "to grab [bin Laden] and bring him to a secure place where we can turn him over to the FBI. . . . If they had said 'lethal action' it would have been a whole different kettle of fish, and much easier."

* al Qaeda and Saddam Hussein: Rumsfeld changed the rules of fighting against terrorists, focusing on one primary goal-killing them. Rumsfeld streamlined rules of engagement allowing soldiers on the ground to act quickly on new information. Rumsfeld also moved new special operations units under the control of the Pentagon. The book reveals how one such unit, the secret Grey Fox, could turn on cell phones without the enemy knowing it, allowing the CIA Predator to use the phone signal for a missile strike.