Attorney General Michael B. Mukasey, who spent most of his adult life as a federal prosecutor and a judge, will return to the courtroom later this month to argue a case before the Supreme Court, officials said yesterday.

Mukasey will urge the justices to reinstate a sentence overturned by an appeals court in the case of Ahmed Ressam, an al-Qaeda operative convicted of a plot to blow up Los Angeles International Airport in 1999.

The last attorney general to handle a case before the high court was Janet Reno in 1996, court officials said. William P. Barr and Richard Thornburgh also argued cases while serving as attorneys general in the administration of George H.W. Bush.

Justice Department spokesman Peter A. Carr said there is a custom, not always followed, for attorneys general to argue at least one Supreme Court case during their term. He declined to comment on why Mukasey chose the Ressam case.

Mukasey, 66, is a retired federal judge who oversaw several high-profile terrorism-related trials while on the bench in New York City. He is scheduled to appear for Supreme Court arguments on March 25 and plans to conduct moot-court sessions to prepare, officials said.

Ressam was arrested near the U.S.-Canada border in December 1999 after customs agents found 124 pounds of explosives in the trunk of his car as he disembarked from a ferry in Port Angeles, Wash. He was convicted in 2001 of nine charges in connection with the plot, but after ceasing cooperation with the FBI was sentenced to 22 years in prison in 2005.

The U.S. Court of Appeals for the 9th Circuit threw out the sentence in 2007 after finding that one of the charges was applied improperly. The federal government disagrees and wants the sentence reinstated.

So what will Eliot Spitzer do next, assuming he escapes criminal prosecution and disciplinary sanction following his alleged involvement with a high-end prostitution ring? If he follows the example of his three living predecessors as governor, he will join a law firm.

George Pataki last year joined Chadbourne & Parke as a counsel in the environmental practice, and Mario Cuomo has long hung his hat at Willkie Farr & Gallagher. Hugh Carey survived the 1987 collapse of Finley Kumble Wagner Underberg Manley Myerson & Casey and is now a partner in the Manhattan office of Harris Beach.

But Spitzer's reasons for resigning office mark him as something of a different candidate.

"It matters how you leave," said the chairman of one large New York firm who asked to remain unnamed.

Former governors and other prominent political names generally have a cachet with clients that makes them attractive to firms, he said, but the scandal forcing Spitzer out of office may have exhausted the current governor's quotient of good will.

"He would need to rehabilitate himself first," agreed the managing partner of another large New York firm who also requested anonymity. It would probably be a year or more before any firm would even consider bringing the soon-to-be ex-governor aboard, the partner said. "He's radioactive in this environment," he added.