Senate Judiciary Committee Chairman Patrick J. Leahy (D-Vt.) yesterday invited federal Judge Jay S. Bybee to testify about his role in preparing two Justice Department memos that allowed interrogators to engage in techniques such as simulating drowning and slamming prisoners against a wall.

    Bybee, who has been a judge on the U.S. Court of Appeals for the 9th Circuit for the past six years, previously headed the department's Office of Legal Counsel (OLC). During his tenure there, he offered advice to the Bush administration about whether CIA interrogation methods would violate laws banning torture.

    His signature appears on memos from August 2002 that determined that al-Qaeda suspect Zayn al-Abidin Muhammed Hussein, better known by the nom de guerre Abu Zubaida, could be deprived of sleep for as long as 11 days and could be subjected to waterboarding.

    A year after those memos were issued, but before they became public, Bybee realized one of his long-standing professional ambitions when he was confirmed by the Senate to the federal bench.

    "There is significant concern about the legal advice provided by OLC while you were in charge, how that advice came to be generated . . . and the role played by the White House," Leahy said in his letter to the judge.

    In recent days, left-leaning activists including John Podesta, who led President Obama's transition team, have called for Bybee's impeachment.

    Bybee is one of three Bush OLC lawyers under investigation by Justice Department ethics watchdogs. The department's Office of Professional Responsibility is examining whether Bybee, John C. Yoo and Steven G. Bradbury followed professional standards when they drafted memos underpinning interrogation techniques that critics liken to torture. The ethics watchdogs have the power to make recommendations to state legal disciplinary boards.

    In a statement published in part yesterday by the New York Times, Bybee defended his conclusions. "The central question for lawyers was a narrow one; locate, under the statutory definition, the thin line between harsh treatment of a high-ranking Al Qaeda terrorist that is not torture and harsh treatment that is. I believed at the time, and continue to believe today, that the conclusions were legally correct."

    "The legal question was and is difficult," he said. "And the stakes for the country were significant no matter what our opinion. In that context, we gave our best, honest advice, based on our good-faith analysis of the law."

    According to the Times, Bybee said he was issuing a statement following reports, including in The Washington Post, that he had regrets over his part in writing the memos.

    "I've heard him express regret at the contents of the memo," said a fellow legal scholar and longtime friend who was quoted in The Post last week, speaking on the condition of anonymity. "I've heard him express regret that the memo was misused. I've heard him express regret at the lack of conte?t -- of the enormous pressure and the enormous time pressure that he was under. And anyone would have regrets simply because of the notoriety."

    Erica Chabot, a spokeswoman for Leahy, said he has not sent letters inviting testimony from Yoo and Bradbury but did not foreclose the possibility that they would be contacted. Both men have left government service.

    A lawyer for Bybee, Maureen Mahoney, had no immediate response to requests for comment on the Leahy letter.

    ---------

    Staff writer Karl Vick contributed to this report.