WASHINGTON — The Senate confirmed Judge Michael Mukasey as attorney general last night to replace Alberto Gonzales, who was forced from office in a scandal over his handling of the Justice Department.

President Bush thanked the Senate, even though the margin had been whittled down from nearly unanimous by a sharp debate over Judge Mukasey’s refusal to say whether the waterboarding interrogation technique is torture.

“He will be an outstanding attorney general,” Mr. Bush said in a statement from his ranch in Crawford, Texas.

Republicans were solidly behind Mr. Bush’s nominee. Democrats said their votes were not so much for Judge Mukasey as they were for restoring a leader to a Justice Department left adrift after Mr. Gonzales’s resignation in September.

In the end, Judge Mukasey was confirmed as the nation’s 81st attorney general by a 53-40 vote. Six Democrats and one independent joined Republicans in sealing his confirmation.

The choice, according to one of those Democrats, was essentially between “whether to confirm Michael Mukasey as the next attorney general or whether to leave the Department of Justice without a real leader for the next 14 months,” Senator Feinstein of California said.

“This is the only chance we have,” she said, referring to Mr. Bush’s threat to appoint an acting attorney general not subject to Senate confirmation.

But members of her own party didn’t agree. Judge Mukasey, his opponents argued, refused to say whether waterboarding is torture and put the onus on Congress to pass a law against the practice.

The confirmation vote capped 10 months of scandal and resignations at the Justice Department. Judge Mukasey’s chief Democratic patron, Senator Schumer, drove the probe into the purge of nine federal prosecutors that helped push Mr. Gonzales out.

The debate came after a tense day of negotiations that at one point featured the Senate majority leader, Harry Reid, threatening to postpone Judge Mukasey’s confirmation until December. His confirmation had long been certain despite the debate over waterboarding.

Waterboarding, used by interrogators to make someone feel as if he is going to drown, is banned by domestic law and international treaties. But U.S. law applies to Pentagon personnel and not the CIA. The administration won’t say whether it has allowed the agency’s employees to use it against terror detainees.

“The United States will not be viewed kindly if we confirm as chief law enforcement officer of this country someone who is unwilling or unable to recognize torture when he sees it,” Senator Durbin of Illinois said.

Judge Mukasey has called waterboarding personally “repugnant,” and in a letter to senators said he did not know enough about how it has been used to define it as torture. He also said he thought it would be irresponsible to discuss it since doing so could make interrogators and other government officials vulnerable to lawsuits.

“He felt that he could not make that pronouncement without placing people at risk to be sued or perhaps even criminally prosecuted,” the ranking Republican on the Judiciary Committee, Senator Specter of Pennsylvania, said.

Judge Mukasey, who received a strong endorsement from Mr. Schumer, was the White House’s first choice to replace Mr. Gonzales. Mr. Gonzales announced his resignation on August 27, and the White House interviewed Judge Mukasey the same day. Three weeks later, Mr. Bush introduced the 66-year-old Judge Mukasey as “a tough but fair judge” and asked the Senate to confirm him quickly.

Judge Mukasey, the former chief U.S. district judge in the Manhattan courthouse just blocks from ground zero, was first appointed to the bench in 1987 by President Reagan. He also worked for four years as a trial prosecutor in the U.S. Attorney’s Office in New York’s Southern District — one of the Justice Department’s busiest and highest-profile offices in the country.

Judge Mukasey oversaw some of the nation’s most significant terror trials in the years before and after the attacks of September 11, 2001.

He sentenced Omar Abdel Rahman, known as the “blind sheik,” to life in prison for a plot to blow up New York City landmarks, and he signed in 2002 the material witness warrant that let the FBI arrest American citizen Jose Padilla. That warrant marked the start of a case that wound its way through several federal courts as the government declared Padilla an enemy combatant and held him for 31⁄2 years before he was convicted last month on terrorism-related charges.

In an opinion article in The Wall Street Journal, Judge Mukasey criticized American national security law as too weak in some areas by noting that prosecutors are sometimes forced to reveal details of cases at the risk of tipping off terrorists. He is also a supporter of the government’s anti-terror USA Patriot Act, wryly writing in 2004 that the “awkward name may very well be the worst thing about the statute.”

Judge Mukasey, a partner at New York-based law firm Patterson Belknap Webb & Tyler, is also a close friend to Mayor Giuliani, a Republican. He stepped down as an adviser to Mr. Giuliani’s presidential campaign, on which he served as part of an advisory committee on judicial nominations.

Besides Senators Schumer and Feinstein, Democrats voting to confirm Mr. Mukasey were: Senators Bayh of Indiana, Carper of Delaware, Landrieu of Louisiana, and Nelson of Nebraska. Of the Senate’s two independents, Senator Lieberman of Connecticut voted for confirmation and Senator Sanders of Vermont voted against.

Not voting were Democratic presidential candidates, Senators Biden of Delaware, Clinton of New York, Dodd of Connecticut, and Obama of Illinois. All four had said they opposed Judge Mukasey’s nomination.

A Republican presidential candidate, Senator McCain of Arizona, also was absent, as were GOP Senators Alexander of Tennessee and Cornyn of Texas.