WASHINGTON -- Attorney General Alberto Gonzales's already tenuous hold on his job was further weakened by more than seven hours of often combative Senate questioning that underscored skepticism from key Republicans about whether he should remain in the job.

The reactions of Republicans, especially those who had been supportive of the attorney general, will be key for the White House in deciding whether to signal to Mr. Gonzales that he should step aside over the controversial firing of eight U.S. attorneys.

Many Democrats already are on record insisting the attorney general resign. Mr. Gonzales's top aides had hoped their boss would emerge from a Senate Judiciary Committee hearing yesterday without any additional Republicans calling for his resignation. The hearing, called by Democratic Sen. Patrick Leahy of Vermont, the committee's chairman, was billed by Democrats as a way to get to the bottom of the firings.

But it was Republican senators who asked questions that went to the heart of earlier misleading and incomplete answers from Mr. Gonzales and others at the Justice Department in explaining how the attorneys were fired. It was Republicans who returned repeatedly to questions about how Mr. Gonzales could stand by the firings, yet not explain why each one was carried out.

In the fourth hour of questioning, Republican Sen. Tom Coburn, of Oklahoma, told the attorney general that he should suffer the consequences of multiple miscues in handling the matter. "The best way to put this behind us is your resignation," Sen. Coburn said, becoming the first Republican on the Judiciary Committee to make such a call.

Even conservative Republican Senators John Cornyn of Texas and Jeff Sessions of Alabama, who are friendly to the attorney general and the administration, expressed misgivings about the handling of the firings and about the shifting explanations offered for them. They put the onus on Mr. Gonzales to get himself out of the jam, and made it clear he had a heavy burden to do so.

The firings have become known among prosecutors as the Pearl Harbor Day Massacre, a reference to the date -- Dec. 7 -- when a midlevel Justice official telephoned seven of the eight attorneys to fire them. After the department described the firings to Congress as being for "performance" reasons, several of the dismissed prosecutors went public to defend their reputations. Democrats have raised questions about whether the firings of Carol Lam of San Diego and David Iglesias of New Mexico were related to politically sensitive investigations.

Contradictory explanations provided by Mr. Gonzales and his staff fueled what might otherwise have remained a low-wattage political fight. U.S. attorneys are presidential political appointees, approved by the Senate.

As yesterday's hearing began, Mr. Gonzales stood alone in fighting for his job, despite White House assertions that he maintained the confidence of his close friend, President Bush. He sat by himself at a red-draped table adorned with a small bottle of water, an array of two dozen cameras clicking as he took his oath.

His wife, Rebecca, sat in the audience, three chairs from a line of pink-garbed protesters, some holding signs that read, "resign," and, "you're hurting America." One person held a card that counted the number of "I don't recall" answers given by the attorney general (within the first 100 minutes the count was 29).

Little new information about the dismissals was unearthed in questions. Mr. Gonzales, who by turns was defensive, weary and combative, began by apologizing to the eight U.S. attorneys. "Those eight attorneys deserved better, they deserved better from me and from the Department of Justice, which they served selflessly for many years," he said.

Quickly, however, Mr. Gonzales became bogged down in a back-and-forth with Pennsylvania Sen. Arlen Specter, the top Republican on the committee, who has been a persistent, but measured, Gonzales critic. The two sparred over whether the attorney general was ill-prepared for a March 13 press conference in which he disavowed involvement in the firings. "I don't think you're going to win a debate about your preparation, frankly," Mr. Specter rebuked the attorney general.

Mr. Gonzales told the senators that he and his deputy, Paul J. McNulty, recently reviewed the decision to oust the prosecutors. "What I have concluded is that, although the process was nowhere near as rigorous or structured as it should have been, and while reasonable people might decide things differently, my decision to ask for the resignations of these U.S. attorneys is justified and should stand," he said.

Mr. Gonzales had his defenders, led by Sen. Orrin Hatch (R., Utah), who decried Democrats for attacking the attorney general's credibility. But just after lunch, Sen. Coburn methodically walked Mr. Gonzales through the "performance" reasons given for the firings and then pounced, asking: "Why should you not be judged by the same standards with which you judged these dismissed U.S. attorneys?"

Mr. Gonzales demurred. Sen. Coburn then said he did not believe the prosecutor firings were done for "improper" reasons. But, he said, the attorney general should step aside. Mr. Gonzales slumped his shoulders and appeared deflated.