Washington ? I. Lewis “Scooter” Libby on Tuesday abandoned plans to testify in his own defense and decided against calling his former boss, Vice President Dick Cheney, to help defend him in the CIA leak trial.

The announcement in U.S. District Court by defense attorney Theodore Wells came after several days in which Libby’s attorneys had inched in that direction.

The formal reversal in their announced tactics prompted Judge Reggie Walton to advise them the decision would limit how far they could go in using memory flaws as Libby’s defense to perjury and obstruction charges.

Defense attorneys put in nearly two hours of testimony Tuesday from Cheney’s current national security adviser, John Hannah, about how busy Libby was in 2003 with the war in Iraq and other pressing national security issues while serving Cheney as both national security adviser and chief of staff.

Informed of Libby’s decision, Walton said, “I understood the defense was going to be that these issues were of such significance that they so overwhelmed him so it was reasonable for him to forget” when he first learned that war critic Joseph Wilson’s wife, Valerie Plame, worked for the CIA.

Libby is charged with lying to the FBI and a grand jury about his talks with reporters concerning Plame and obstructing the investigation of how her identity leaked in 2003. Libby says his memory failed him.