In a 45-page filing on Monday, Libby's lawyers said reporters have "no right, under the Constitution or the common law, to deprive Mr. Libby of evidence that will help establish his innocence at trial."
Libby, 55, Vice President Dick Cheney's former chief of staff, is charged with perjury and obstruction of justice for lying to the FBI and a federal grand jury about how he learned about CIA operative Valerie Plame and what he subsequently told reporters about her.
The key to Libby's defense is whose memory is correct, Libby's or three reporters who talked with him in June and July 2003. His lawyers said they need the reporters' records to use in cross-examining them and government officials, who, the lawyers said, may be "shading" the truth to protect themselves or their bosses.
Lawyers for NBC News, The New York Times and Time Inc. want U.S. District Judge Reggie B. Walton to limit Libby's subpoenas. The media groups say the subpoenas are so broad that they threaten the integrity of their news-gathering operations by targeting all of their employees, not just the three reporters involved in the case.
Syndicated columnist Robert Novak named Plame in a column on July 14, 2003, eight days after her husband, former U.S. Ambassador Joseph Wilson, alleged in an opinion piece in The New York Times that the Bush administration had twisted prewar intelligence on Iraq to justify going to war.
The CIA sent Wilson to Niger in early 2002 to determine whether there was any truth to reports that Saddam Hussein's government had tried to buy yellowcake uranium from Niger to make a nuclear weapon. Wilson discounted the reports. But the allegation nevertheless wound up in President Bush's 2003 State of the Union address.
Libby's indictment grew out of conversations he had with NBC's Tim Russert, Time magazine's Matthew Cooper and former New York Times reporter Judith Miller in June and July 2003, a two-month period in which the White House, according to Special Counsel Patrick Fitzgerald, was mounting a campaign to undermine Wilson's charges about the Iraq war.
Generally, Libby's subpoenas seek all documents prepared or received by any employee of NBC News, The New York Times and Time that refer to Plame and her husband before Novak's column was published.
The subpoenas also seek drafts of articles, even those that were not published; communications between reporters and editors, and e-mail exchanges among any reporters about Plame or Wilson.
The defense attorneys said in Monday's filing that reporters' notes may be useful to Libby's case if they do not mention Plame. Libby argues that Plame was a "peripheral" issue and that he was focused on attacking her husband's charges on the merits, not smearing him.
Libby's lawyers want uncensored copies of Miller's notes to use to cross-examine her about discrepancies in her public statements and writings about the case. Miller spent 85 days in jail last year, refusing to name Libby as her source.
The defense team also wants NBC reporter Andrea Mitchell's records because the lawyers believe she told Russert about Plame's work at the CIA, and that Russert, in turn, told Libby.
Libby's lawyers want records generated by Cooper's colleagues because he was part of a team of six reporters who worked on the dispute between Wilson and the White House over the prewar intelligence.
Last week, Karl Rove testified for the fifth time before the panel investigating the leak.
But still, testifying is a risk for Rove, CBS News legal analyst Andrew Cohen said.
"Each time you go before a grand jury as a target or a subject or a person of interest — or anyone else other than a plain old witness — you put yourself in legal jeopardy," Cohen said.