WASHINGTON (CNN) -- During five hours of heated wrangling with frustrated Senate Democrats, Attorney General Michael Mukasey refused Wednesday to budge from his position that the controversial interrogation technique known as waterboarding is not clearly illegal.
Attorney General Michael Mukasey testifies Wednesday on Capitol Hill.
Mukasey announced on the eve of the hearing that he would not give in to demands for an answer on the issue. Waterboarding was a key issue in Mukasey's confirmation three months ago.
Waterboarding is prohibited by the U.S. military.
In 2006, the CIA and Pentagon banned the technique, which involves strapping an interrogation subject to a surface, covering the person's face with cloth and pouring water on the face to imitate the sensation of drowning.
If the Justice Department joined other nations and specifically defined waterboarding as illegal, CIA interrogators might be vulnerable to retroactive legal action in either U.S. or international courts.
Mukasey said he would not and did not need to discuss the legality of something that would only serve to provide information to the enemy. Watch more of Mukasey's testimony »
The hearing ended as it began -- with a demand from committee Chairman Patrick Leahy, D-Vermont, for an unequivocal declaration that waterboarding constitutes torture and is illegal.
"It is not enough just to say that waterboarding is not currently authorized," Leahy said. "The attorney general of the United States should be able to declare that it is wrong, it is illegal, and it is beyond the pale. It has been for over a century."
Mukasey's testimony marked his first visit to Capitol Hill since October, when he barely survived a confirmation vote after a testy confrontation on the torture issue.
In October, Mukasey insisted he could not make a declaration of legality because he had not been briefed on classified programs.
On Wednesday, he took a different approach but ended up in the same place. Now that he has been briefed, he said, he can see that reasonable people may differ.
"There are some circumstances where current law would appear clearly to prohibit the use of waterboarding. Other circumstances would present a far closer question," he testified.
That prompted Sen. Sheldon Whitehouse, D-Rhode Island, to demand Mukasey identify "reasonable people" who differ with him. When Mukasey suggested the Senate included such people, Whitehouse rejected the answer, insisting the Senate had spoken in passing a measure outlawing the technique. But Mukasey pointed to another Senate vote in which such a declaration was rejected.
On Wednesday, Sen. Edward Kennedy joined the Democratic chorus complaining of Mukasey's non-answer on the waterboarding question.
"It's like you're opposed to stealing but not quite sure that bank robbery would qualify," Kennedy said.
Mukasey is expected to face a repeat battle when he appears before the House Judiciary Committee next week. E-mail to a friend
CNN's Terry Frieden contributed to this report.