Lawyers for a former top White House aide want access to classified intelligence briefings to show that he had more pressing matters on his mind than lying about leaking the identity of a CIA operative to get even with her husband for criticizing President Bush.

In a 21-page filing in federal court Tuesday, lawyers for I. Lewis "Scooter" Libby accused prosecutors of withholding evidence they say they need to mount a defense.

Specifically, Libby's lawyers are seeking copies of the highly secretive President's Daily Brief, a summary of intelligence on threats against the United States, given to Bush from May 6, 2003, to March 24, 2004.

Libby, the former chief of staff to Vice President Dick Cheney, was indicted last year on charges that he lied to the FBI and a federal grand jury about how he learned CIA operative Valerie Plame's identity and when he subsequently told reporters.

Plame's identity was published in July 2003 by columnist Robert Novak after her husband, former U.S. Ambassador Joseph Wilson, accused the Bush administration of twisting intelligence about Iraq's efforts to buy uranium "yellowcake" in Niger. The year before, the CIA had sent Wilson to Africa to determine the accuracy of the uranium reports.

"These documents will establish that Mr. Libby was immersed throughout the relevant period in urgent and sensitive matters, some literally matters of life and death," his lawyers wrote.

"Based in part on the documents, Mr. Libby will show that, in the constant rush of more pressing matters, any errors he made in his FBI interviews or grand jury testimony, months after the conversations, were the result of confusion, mistake or faulty memory, rather than a willful intent to deceive," the lawyers argued.

The dates of the intelligence briefings are significant to Libby's case. May 6, 2003, marks the first time the media referred to Wilson's findings in Niger, and March 24, 2004, was Libby's last appearance before the grand jury.

Libby's lawyers also want a federal judge to force special prosecutor Patrick Fitzgerald to provide copies of notes that Libby took during the same time period and any security assessment made by the CIA to determine whether any damage was done by the Plame disclosure.

"It is material to the preparation of the defense to ascertain whether any damage to national security in fact resulted from the disclosure of Ms. Wilson's employment status," Libby's lawyers said.

In a Jan. 9 letter to Libby's lawyers, Fitzgerald said he believes he is obligated to turn over only documents in the FBI's possession. Fitzgerald also said he did not have -- nor did he request -- many of the documents that Libby's lawyers want.

"As you are no doubt aware, the documents referred to as the Presidential Daily Briefs are extraordinarily sensitive documents which are usually highly classified," Fitzgerald wrote. "We have never requested copies of any PDBs."

Libby's lawyers said they believe Fitzgerald should obtain the documents from the CIA and the vice president's office and turn them over to the defense team. The defense lawyers said they reserve the right to seek records kept by other government agencies, including the State Department, Office of the President and the National Security Council.