COMPANY MAN: Thirty Years of Controversy and Crisis in the CIA. By John Rizzo. Scribner. 336 pages. $28.

There is a moment in John Rizzo’s new memoir when the longtime CIA lawyer has the chance to change history. It is March 2002, and Rizzo has just been briefed on the agency’s proposals for interrogating suspected terrorists.

Rizzo walks the grounds of the CIA, smoking a cigar, thinking about waterboarding and other tactics that seem “sadistic and terrifying.”

Rizzo realizes that, on his own say-so, he can end the discussion right there. With the stroke of a pen, Rizzo, the CIA’s acting general counsel, could kill the program before it starts.

Then he thinks about what would happen if terrorists struck again. People would blame the CIA. Rizzo would blame himself. And he couldn’t deal with that.

So despite his reservations, Rizzo sends the interrogation proposal to the Justice Department, beginning a process that gave the green light to tactics the United States once considered and prosecuted as torture.

Moments like this occur again and again in the roughly six chapters Rizzo dedicates to the CIA’s post-9/11 response: People set aside nagging questions about morality (should we?) and focused instead on the legalistic question (can we?).

Rizzo’s portrayal of key meetings offers an unprecedented and sometimes startling look at how uncomfortable the enhanced-interrogation techniques made people.

Rizzo paints a revealing picture, one in which fear hung over important decisions. Fear of another attack, fear of blame, fear of political liability.

Rizzo’s book makes an important contribution to history and the debate over interrogation. And it serves as a reminder of how much fear drives decision-making in Washington.