The United States has not employed waterboarding since 2003, though George W. Bush's decision to allow the controversial, and arguably illegal, tactic has continued to draw criticism and scrutiny.
According to interrogation memos uncovered in 2009, Al Qaeda operative Abu Zubaydah was subjected to waterboarding 83 times in Aug. 2002, and 9/11 mastermind Khalid Sheikh Mohamed was subjected to waterboarding 183 times in March 2003.
In his new memoir, Mr. Bush defends the use of waterboarding: "At my direction, Department of Justice and CIA lawyers conducted a careful legal review. The enhanced interrogation program complied with the Constitution and all applicable laws, including those that ban torture.
"There were two that I felt went too far, even if they were legal. I directed the CIA not to use them. Another technique was waterboarding, a process of simulated drowning. No doubt the procedure was tough, but medical experts assured the CIA that it did no lasting harm."
Bush writes that he has no regrets. "We only used the technique on three people," he says. "We gained valuable information to protect the country, and it was the right thing to do, as far as I'm concerned."
On NPR's politics blog, Frank James highlights that "just because something is legal doesn't necessarily make it the moral choice... Put plainly, the question for the ex-president is, as a Christian, does he believe Jesus would approve waterboarding?"
President Obama banned the controversial tactic on his second day in the Oval Office. Attorney General Eric Holder said during his confirmation hearings that "waterboarding is torture."