I'd sure like to be the prosecutor who's going to have Cheney under oath.
Here's what Cheney is expected to testify about:
Libby argues that he was so busy with pressing national security crises that he forgot details of those conversations and misspoke about them. Cheney could help the defense establish that Libby was indeed at the center of a maelstrom of pressing security matters.
Yes, Libby was so busy it just slipped his mind that he outed a CIA agent whose husband exposed the fake Niger/uranium/Saddam connection that then so outraged the administration.