Mr. Bush said that he consulted with his lawyers before deciding to use waterboarding on terrorism suspect Khalid Sheikh Mohammed after he was captured in March 2003.
"The first thing you do is ask what's legal?" Mr. Bush said, according to CNN. "What do the lawyers say is possible? I made the decision, within the law, to get information so I can say to myself, 'I've done what it takes to do my duty to protect the American people.' I can tell you that the information we got saved lives."
The former president also said his decision to overthrow the regime of Saddam Hussein will one day be vindicated as the establishment of democracy in the Middle East, the Detroit Free Press reported, and that "people will say, 'Thank God they never lost faith.'"
Mr. Bush, in his biggest speech since leaving the White House, echoed the sentiments of former Vice President Dick Cheney, who last week also defended the administration's interrogation practices.
Unlike Cheney, however, Mr. Bush was careful to avoid criticizing the current president's policies.
"Nothing I am saying is meant to criticize my successor," Mr. Bush said, CNN reported, speaking before the Economic Club of Southwestern Michigan. "There are plenty of people who have weighed in. Trust me, having seen it firsthand. I didn't like it when a former president criticized me, so therefore I am not going to criticize my successor. I wish him all the best."
Mr. Bush also said he remains a "free-market guy," though he insisted the Troubled Asset Relief Program was necessary in order to prevent a depression.
When asked what he wants his legacy to be, Mr. Bush said he'd like to be known as "the man showed up with a set of principles, and he was unwilling to compromise his soul for the sake of popularity."
Mr. Bush now heads to Toronto, where he will sit with Bill Clinton today for a $230-plus per ticket "conversation" at the Metro Toronto Convention Centre focusing on "challenges facing the world in the 21st century."