Washington ? Michael B. Mukasey, a former federal judge regarded as an expert on national security issues, has emerged as the leading candidate to replace Alberto Gonzales as attorney general, several conservatives close to the White House said Saturday.

The sources, who spoke on condition of anonymity because it was internal White House deliberations, said that President Bush is close to announcing his nominee, possibly doing so as early as Monday, and that Mukasey has vaulted to the top over other contenders, including former solicitor general Theodore B. Olson, whose chances may have been damaged after the Senate’s top Democrat vowed to block his confirmation.

One source close to the White House, describing Mukasey as the clear “front-runner,” said Bush advisers appear to have decided that “they didn’t want a big fight over attorney general” in the Senate, especially when other qualified candidates are also available.

The source said Olson, who represented Bush in the Supreme Court fight over the contested 2000 election, would be seen as “very political,” despite his outstanding legal credentials.

Another well-connected GOP source said that Mukasey is “the leading candidate.” He described Mukasey – the former chief judge of the U.S. District Court for the Southern District of New York – as a conservative on counterterrorism issues, such as electronic surveillance, and said that he has a solid reputation and is seen by Bush aides as “confirmable.”

That posture may not sit well with some conservatives in the legal world, who have relished the prospect of a confirmation fight over Olson. But it may signal a White House desire to restore order to the Justice Department, which has experienced considerable turmoil because of controversies surrounding Gonzales, including his handling of the firing of federal prosecutors.

“I think Mike Mukasey would be a first-rate pick. He’s really a tough-as-nails judge. He has very strong law-and-order values,” said Jay P. Lefkowitz, a former White House domestic policy adviser who practices law in New York. “The Justice Department has been really beleaguered over the last few months, and bringing someone in like Mike Mukasey will be a real shot in the arm for the department.”

White House press secretary Dana Perino declined Saturday night to comment on any possible names for attorney general but said an announcement “will be made relatively quickly.”

Mukasey, 66, spent 19 years on the federal bench in Manhattan, including his last six years as the district’s chief judge. He was appointed by President Ronald Reagan and retired in 2006, returning to private practice at his old law firm, Patterson Belknap Webb & Tyler.

As a federal judge, Mukasey presided over some of the nation’s most high-profile terrorism trials, including those of Omar Abdel Rahman, the “blind sheik,” and 11 others in connection with the 1993 World Trade Center bombing. Mukasey was the first judge to handle the case of Jose Padilla, after the federal government declared him an “enemy combatant” in 2002 and sought his indefinite detention without legal recourse. After Mukasey rejected the latter motion, the federal government had the case transferred to another court, in South Carolina. (Padilla has since been convicted in Florida in a separate terrorism trial.)