The leak was intended, the court papers suggested, as a rebuttal to the Op-Ed article published in the New York Times on July 6, by Joseph C. Wilson, IV, a former ambassador and the husband of Ms. Plame. Mr. Wilson wrote that he had traveled to Africa in 2002 after Mr. Cheney had raised questions about possible nuclear purchases. Mr. Wilson wrote that he concluded it was "highly doubtful" Iraq had sought to nuclear fuel from Niger.

At Mr. Cheney's office, the Op-Ed article was viewed "as a direct attack on credibility of the Vice President (and the President) on a matter of signal importance: the rationale for the war in Iraq," according to the court papers.

The presidential authorization was provided, the court papers said, in advance of a meeting on July 8, 2003 between Mr. Libby and Judith Miller, then a reporter for the New York Times. Mr. Libby brought a brief abstract of the N.I.E.'s key judgments to the meeting with Ms. Miller in the lobby of the St. Regis Hotel about two blocks from the White House.

Mr. Libby testified, the prosecutors said, that he was "specifically authorized in advance of the meeting to disclose the key judgments of the classified N.I.E. to Miller on that occasion because it was thought that the N.I.E. was "pretty definitive" against what Ambassador Wilson had said and that the Vice President thought that it was "very important" for the key judgments of the N.I.E. to come out."

The court filing said that Mr. Libby said "he understood that he was to tell Miller, among other things, that a key judgment of the N.I.E. held that Iraq was 'vigorously trying to procure' uranium." Mr. Libby, the prosecutors, said, testified that the meeting with Ms. Miller was the "only time he recalled in his government experience when he disclosed a document to a reporter that was effectively declassified by virtue of the president's authorization that it be disclosed."

Ms. Miller never published anything about the contents of the intelligence estimate.

Mr. Libby testified that he first told Mr. Cheney that he could not conduct such a conversation with Ms. Miller because the intelligence estimate on Iraq was classified. Mr. Libby testified that Mr. Cheney later told him that Mr. Bush had authorized the release of "relevant portions."

In addition, Mr. Libby told the grand jury that he also spoke with David Addington, then a lawyer for Mr. Cheney, whom Mr. Libby regarded as an expert on national security law. "Mr. Addington opined that Presidential authorization to publicly disclose a document amounted to declassification of the document," the court filing said.