“The reason Republicans are not coming over the hill like the cavalry is the best defense you can give is it was poorly handled,” said Senator Lindsey Graham, Republican of South Carolina, a member of the Judiciary Committee. “That is as good as it gets.”

The Senate Judiciary Committee on Thursday is to consider subpoenas of its own.

Senator Patrick J. Leahy, the Vermont Democrat who is the chairman of the panel, said Wednesday evening that he expected to win the authority to force the testimony. “Every day there are thousands of good, loyal Americans who stand in courtrooms, raise their right hand and swear to tell to truth, the whole truth and nothing but the truth and are proud to do it,” Mr. Leahy said. “It is amazing that thousands of ordinary Americans can do it, but they are kind of special and they don’t have to.”

Some Congressional Republicans said privately that the administration’s proposal might be a tough sell because many Americans would question why the officials were unwilling to talk under oath — a position the administration attributes to a desire to not set a precedent.

But others sought to make the case that those appearing would still be required to be truthful or face a charge of misleading Congress. “If we find that there’s a lie, these people can go to jail just like they were under oath,” said Representative Chris Cannon of Utah, the senior Republican on the subcommittee that approved the subpoenas.

Republican members of the Senate Judiciary Committee met privately Wednesday to discuss their approach, and a group of them later had lunch at the Justice Department with Mr. Gonzales, who was trying to bolster his core support before their committee’s session Thursday.

Senator Jon Kyl, Republican of Arizona, whose position on the fate of Mr. Gonzales wouldprobably influence other colleagues, said the attorney general assured them that none of the prosecutors was removed to halt a criminal inquiry — an accusation that has helped fuel the furor.

“He again reiterated to us that in none of the cases of U.S. attorneys being asked to resign was it because of any ongoing investigation, let alone an investigation involving a political person,” said Mr. Kyl, who said there was no talk of Mr. Gonzales’s resignation at the meeting.