The Bush administration lawyer who wrote the legal justification for the CIA’s use of harsh interrogation tactics against Al-Qaeda detainees said Friday they were used even though it wasn’t clear whether there would be lasting effects on individuals subjected to them.

John Yoo, the Deputy Assistant U.S. Attorney General early in the Bush administration, questioned the fairness of the newly released Senate Intelligence Committee report on the CIA’s interrogation program after the Sept. 11, 2001, attacks, but agreed with its finding that he and other administration officials did not know if so-called “enhanced interrogation techniques, including waterboarding,” would cause permanent damage to detainees.

“We did not examine this question of how long you could use the methods for, or what’s their cumulative effect,” Yoo said in an interview for C-SPAN’s ‘Newsmakers’ program that included Checkpoint and will air on television Sunday morning. “Quite frankly, we didn’t examine them at that time because in the rush of events, we were just focusing on one person, Abu Zubaida, and the use of these methods we hoped would be one or very few times.”

The detainee Yoo referenced was a test-case for the tactics used by the CIA, as the Senate report outlined. Zubaida was waterboarded dozens of times at a “black site” prison in Thailand beginning in August 2002, after being captured in Pakistan earlier that year. 

Some of the methods used by the CIA were adapted from U.S. military training, as Checkpoint noted earlier this week, One source was the U.S. Air Force Survival, Evasion, Resistance and Escape school, which is designed, in part, to prepare U.S. troops “for the conditions and treatment to which they might be subjected if taken prisoner by countries that do not adhere to the Geneva Conventions,” the report says.

The Navy also uses waterboarding in training, but only in a single training exercise. It did not have information about whether there would be any cumulative effect if done repeatedly, the report adds. The use of waterboarding has been widely condemned as torture, including by President Obama.

Yoo said the repeated use of techniques such as sleep deprivation or waterboarding could be considered torture, even if individual instances were not.

“Of course, if you didn’t let someone sleep for many, many days that would probably cross a line,” Yoo said. “It depends when, and a lot of this is factually dependent. It depends on the person.”

Yoo said that he began working on the question of what the CIA could do legally to extract information in March 2002, around the time Zubaida was captured. The Justice Department approved a list of interrogation techniques in in August 2002.

“We basically worked on this issue all the time, around the clock for all of those months,” Yoo said. “And even then, I would be the first to admit that I wish we had more time. I wish we’d have had more people and more time.”

Yoo is now a law professor at the University of California at Berkeley. Critics have tried to have him fired because of his involvement in enabling the CIA tactics, but he laughed it off on Friday when asked if he was concerned about his personal safety or terrorists.

“I don’t worry about it,” he said, “but maybe that’s because I’ve been living in Berkeley so long I’m used to being surrounded by a sea of Marxists.”