A couple of points:
From CNN: Bush further declares that the new techniques proved effective, yielding information on al Qaeda’s structure and operations, and leading to the capture of Ramzi bin al Shibh, the logistical planner of the 9/11 attacks who was captured on the first anniversary of the attacks. And if there were any lingering doubts or conflict about the use of waterboarding, Bush discloses that he received reassurance from an unlikely source: terror suspect Abu Zubaydah.
The former president writes, “His understanding of Islam was that he had to resist interrogation only up to a certain point. Waterboarding was the technique that allowed him to reach that threshold, fulfill his religious duty, and then cooperate.”
Bush elaborates that Zubaydah gave him a direct instruction, “‘You must do this for all the brothers.'”