But former Deputy Attorney General James B. Comey has testified that Justice Department lawyers were balking at recertifying the program early in 2004 and that he thought Mr. Gonzales and Mr. Card rushed to the hospital to persuade Mr. Ashcroft, who was not at full capacity, to overlook his own objections to the program.

Mr. Mueller said that after receiving a call from Mr. Comey he went to the hospital, arriving shortly after Mr. Gonzales and Mr. Card left, and that after he spoke with Mr. Ashcroft he understood that the N.S.A. program was indeed the focus of the dramatic bedside encounter.

There have been repeated instances in which lawmakers have questioned Mr. Gonzales’s competence and his recollection of events. But today’s developments seemed to mark a shift toward suggestions that he actually committed crimes in testifying before Congress.

The four senators who sought a special counsel are all members of the Judiciary Committee. They urged Solicitor General Paul D. Clement in a letter to name an independent counsel from outside the Justice Department. “It has become apparent that the attorney general has provided at a minimum half-truths and misleading statements,” the senators wrote.

While the four were asking for a special counsel, the chairman of the Judiciary Committee, Senator Patrick J. Leahy of Vermont, announced that a subpoena was being issued to Karl Rove, President Bush’s chief political adviser, to provide information on the firings last year of nine federal prosecutors. The White House has asserted executive privilege in resisting Congressional demands for testimony by present and former presidential aides.

The request that the solicitor general name a special counsel to investigate Mr. Gonzales marked a new stage in the long-running controversy over his stewardship of the Justice Department. Mr. Gonzales’s most outspoken critics suggested today that the attorney general might have committed crimes, including perjury and obstruction of justice, when he testified about President Bush’s domestic-surveillance program and the dismissal of the nine United States attorneys.

The four senators — Charles E. Schumer of New York, Dianne Feinstein of California, Russell D. Feingold of Wisconsin and Sheldon Whitehouse of Rhode Island — zeroed in today on Mr. Gonzales’s testimony that there had been no internal dissent over the president’s warrantless eavesdropping program and that an emergency meeting at the White House in March 2004 concerned subjects other than the secret eavesdropping operation.