Libby Lawyers Grill NBC's Russert

Tim Russert, Washington bureau chief of NBC News, uses crutches to walk into U.S. Federal Court in Washington, Wednesday, Feb. 7, 2007 for the I. Lewis "Scooter" Libby perjury trial. (AP Photo/Pablo Martinez Monsivais) (Pablo Martinez Monsivais - AP)

WASHINGTON -- NBC's Tim Russert deflected criticism of his ethics and credibility as he completed a heated second day of cross-examination Thursday in the trial of former White House aide I. Lewis "Scooter Libby.

Russert, who testified that he never discussed outed CIA operative Valerie Plame with Libby, was the final prosecution witness before Special Prosecutor Patrick Fitzgerald rested his three-week perjury and obstruction case. Libby's attorneys will begin calling witnesses Monday.

The journalist was subjected to the kind of interrogation he usually gives guests on his Sunday television show "Meet the Press," as attorneys flashed excerpts of his previous statements on a video monitor and asked him to explain inconsistencies.

A law school graduate, Russert avoided several traps defense attorneys laid before him. He seemed uncomfortable at times, however, as they asked him to explain why he willingly told an FBI agent about a July 2003 conversation with Libby, then gave a sworn statement saying he would not testify about that conversation because it was confidential.

"Did you disclose in the affidavit to the court that you had already disclosed the contents of your conversation with Mr. Libby," asked Theodore Wells, one of Libby's attorneys.

"As I've said, sir ... "Russert began.

"It's a yes or no question," Wells interrupted.

"I'd like to answer it to the best of my ability," Russert said.

"This is a very simple question. Either it's in the affidavit or it's not?" Wells asked. "Did you disclose to the court that you had already communicated to the FBI the fact that you had communicated with Mr. Libby?"

"No," Russert said.

Wells wants to cast Russert as someone who cannot be believed, who publicly championed the sanctity of off-the-record conversations but privately revealed that information to investigators. Russert said he viewed the FBI conversation and testimony to prosecutors differently.

Russert's credibility is under fire because he and Libby tell very different stories about a July 2003 phone call that is at the heart of the case. The question of which to believe could be a critical jury room issue.