The defence has rested after only three days in the trial of a former top aide to US Vice-President Dick Cheney.
Mr Libby did not take the stand in his own defence
The ex-aide, Lewis "Scooter" Libby, is accused of lying to investigators who were trying to find out who leaked the name of a CIA agent to the media.
No-one was ever charged over the original leak of Valerie Plame's name.
The prosecution spent three weeks making its case in a trial that revealed the inner workings of the White House after the invasion of Iraq.
Witnesses included current and former White House officials and some of Washington's top journalists.
But they did not include Mr Libby himself or his former boss Mr Cheney, despite indications last year that the defence would call them.
The case revolved around the publication in July 2003 of Ms Plame's name in the press and the subsequent investigation into who leaked it.
It is a crime knowingly to disclose the identity of an undercover CIA operative.
Former White House spokesman Ari Fleischer
Washington journalists Bob Woodward, Robert Novak and Tim Russert
FBI agent Deborah Bond
Ms Plame and her husband, the former diplomat Joseph Wilson, allege that her name was leaked by the White House in revenge for Mr Wilson's public attacks on the justification for the invasion of Iraq.
Special prosecution Patrick Fitzgerald did not charge anyone with the leak, but indicted Mr Libby on five counts of lying and obstruction.
He attempted to prove during the trial that Mr Libby knew who Ms Plame was earlier than he admits, and that he told other people about her.
The defence attempted to discredit prosecution witnesses by highlighting inconsistencies in their testimony.
A defence witness said Mr Libby had a bad memory - a key part of the strategy of claiming that any untrue statements he may have made to investigators were the innocent errors of a busy man, not an attempt to obstruct the investigation.
Closing statements are expected to begin next Tuesday.