WASHINGTON - A federal judge ordered the CIA on Friday to turn over highly classified intelligence briefings to Vice President Dick Cheney's former top aide to use in preparing the aide's defense against perjury charges.

U.S. District Judge Reggie B. Walton rejected CIA warnings that the nation's security would be imperiled if the presidential-level documents were disclosed to lawyers for I. Lewis "Scooter" Libby, Cheney's former chief of staff.

The judge said the CIA can either delete highly classified portions from the briefing material and provide what amounts to a "table of contents" of what Libby and Cheney received six days a week. Or, Walton said, the CIA can produce "topic overviews" of the matters covered in the briefings.

The judge also ordered the CIA to give Libby an index of the topics covered in follow-up questions that the former White House aide asked intelligence officers who conducted the briefings.

"The court has painstakingly endeavored to ensure that the defendant is provided with information he truly needs to prepare his defense," Walton wrote in a 25-page ruling.

In seeking CIA input late last month, Walton appeared to have been trying to broker a compromise between defense attorneys and prosecutors to avoid a lengthy court battle with the Bush administration over the briefing material.

The judge's order indicates he is ready for such a fight. He set a schedule for the Bush administration to file any objections by March 24.

The ruling is a partial victory for Libby, who is charged with lying in the investigation into the leak of a CIA operative's identity.

But Walton noted in his ruling that most of what he ordered Libby to receive probably won't be revealed to a jury. Any classified evidence that Libby wants to use must be approved by the judge after a secret vetting process established by Congress to ensure protection of government secrets.

Libby, 55, was charged last October with lying to the FBI and a federal grand jury about how he learned and when he subsequently told reporters about CIA operative Valerie Plame. He faces trial in January 2007 on five counts of perjury, false statements and obstruction of justice.

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

Libby's lawyers originally wanted nearly a year of the President's Daily Brief, a summary of some of the government's most sensitive intelligence gathered on threats to the United States.

The lawyers want to use the briefings as the cornerstone of Libby's defense: to show that the former top White House aide had more important matters on his mind and could have easily forgotten or remembered incorrectly "snippets" of conversations he had about CIA operative Valerie Plame.

Special Counsel Patrick Fitzgerald opposed giving Libby any of the briefings and accused the defense of trying to derail the case by "greymail," a process where former government officials have forced dismissals of their cases because they threatened to reveal the nation's secrets at their trials.

"Neither party has it exactly right," Walton wrote.

Libby needs to know the gist of the intelligence briefings to put on a "preoccupation defense," the judge said. But, he said, the former White House aide should be able to refresh his memory by reviewing generalized versions of the intelligence briefings.

"It is inconceivable that the defendant's memory of matters of significance to him have totally vanished," Walton wrote.

The judge also rejected Fitzgerald's arguments that the intelligence briefings belong to the vice president's office and the CIA, two agencies that were not part of the investigation.

Walton said "there can be little doubt" that when Fitzgerald has asked either agency for help in his probe, there has been "a rather free flow" of information.

"These entities have contributed significantly to the investigation and without their contribution it is unlikely that the indictment in this case could have been secured," the judge wrote.

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