Republican as well as Democratic lawmakers challenged the embattled attorney general during an often-bitter five-hour hearing before the Judiciary Committee. Lawmakers confronted Gonzales with documents and sworn testimony they said showed he was more involved in the dismissals than he contended.
"The best way to put this behind us is your resignation," Sen. Tom Coburn of Oklahoma bluntly told Gonzales, one GOP conservative to another.
Gonzales disagreed, rejecting the idea that his departure would put the controversy to rest.
Even with the White House offering fresh support, it was a long day for the attorney general.
Seventy-one times he fell back on faulty memory, saying he could not recall or remember conversations or events surrounding the firings. During breaks in the hearing, sign-waving protesters rose from the audience calling for him to resign.
Digging in as the day wore on, Gonzales defended his decision last year to oust the U.S. attorneys. Congress is investigating whether the firings were politically motivated, which the Bush administration vehemently denies.
"The notion that there was something that was improper that happened here is simply not supported," Gonzales said, adding that he would make the same decisions again.
Gonzales has provided differing versions of the events surrounding the dismissals, first saying he had almost no involvement and later acknowledging that his role was larger - but only after e-mails about meetings he attended were released by the Justice Department to House and Senate committees.
There was no doubt about the stakes involved for a member of President Bush's inner circle, and support from fellow Republicans was critical to his attempt to hold his job.
Calling most of Gonzales' explanations for the firings "a stretch," Republican Sen. Lindsey Graham asked whether the dismissals simply came down to personality disagreements the Justice Department and White House had with the former prosecutors.
"You said something that struck me - that sometimes it just came down to these were not the right people at the right time," said Graham, R-S.C. "If I applied that standard to you, what would you say?"
Ignoring hoots of laughter from the protesters, Gonzales responded: "I believe that I continue to be effective as the attorney general of the United States. We've done some great things."
A number of Democrats have called for Gonzales to resign or be fired, but until Thursday John Sununu of New Hampshire was the only Republican senator to say so.
Bush spokesman Tony Fratto said at the White House that Gonzales "can be effective going forward."
"It's understandable that the senators have been frustrated by the way this decision was communicated and we fully expected that they would take this opportunity to express this frustration," Fratto said.
Gonzales also scrapped with Democrats, most notably committee chairman Sen. Patrick Leahy of Vermont and Charles E. Schumer of New York. Even soft-spoken Sen. Herb Kohl of Wisconsin chastised Gonzales for having "severely shaken the confidence of the American people."
"Would you explain to the American people why it is so important that you should remain in this office?" Kohl asked.
"The moment I believe I can no longer be effective, I will resign as attorney general," Gonzales responded, making it clear he had not reached that point.
Sen. Arlen Specter of Pennsylvania, top Republican on the panel, stopped short of calling for Gonzales to resign - a modest lifeline for the attorney general - even while questioning his credibility.
Specter said the attorney general's answers "did not stick together."
Senators ticked off evidence - based on department documents and testimony from two former senior Justice officials - that Gonzales participated in discussions about at least three of the fired prosecutors: Carol Lam in San Diego, Bud Cummins in Little Rock, Ark., and David Iglesias in New Mexico. In Iglesias' case, Gonzales recalled an Oct. 11 conversation with Bush and White House political adviser Karl Rove about voter fraud concerns during which the prosecutor's name came up. "I now understand that there was a conversation between myself and the president," Gonzales said. In an interview Thursday with The Associated Press, Iglesias said Gonzales has yet to point out a performance-related reason that justifies the firing. The reasons Gonzales has given "are political issues," Iglesias said. "I wish he would shoot straight with the American people." Gonzales faced GOP as well as Democratic challenges to his credibility throughout the day. Sen. Jeff Sessions, R-Ala., told him, "I'm concerned about your recollection," after the attorney general said he could not remember attending a Nov. 27 meeting during which the firings were discussed. Documents show he was there. Later, Sen. Charles Grassley of Iowa criticized Gonzales for now accepting responsibility for the firings after initially saying he had played only a minor role. "Why is your story changing?" Grassley asked. In response, Gonzales replied that his earlier answers had been "overbroad," the result of inadequate preparation. Gonzales maintained a stoic face through most of the hearing, pursing his lips at times, ignoring the protesters wearing orange garb and pink police costumes. The words "Arrest Gonzales" were duct-taped to their backs. He said he made a "mistake I freely acknowledge" for taking a largely hands-off approach to the firings. But "at the end of the day I know I did not do anything improper." Gonzales marched out of the hearing at its conclusion, shortly before 5 p.m., as protesters began singing "Hey, hey, goodbye" from the 1970s hit song by Steam.