WASHINGTON — A powerful business lobby is preparing a multimillion-dollar campaign to aid the White House in its quest to win approval for conservative judges, a move that could transform the ideological battles over the federal judiciary and the Supreme Court.

The new effort on behalf of some of the nation's biggest manufacturers will increase the cost, visibility and intensity of an already-divisive confirmation process, one dominated by social issues and civil rights until now.

The shift puts the business lobby on the same side as social conservatives. The corporate world long has shied away from such controversial issues as abortion but eagerly supports the White House efforts to rein in what it calls frivolous lawsuits against businesses and physicians.

The engineer is longtime Bush friend and former Michigan Gov. John Engler, who recently took the helm of the National Association of Manufacturers, which represents such large, blue-chip firms as Boeing and General Motors, as well as 10,000 small and medium-sized manufacturers.

Engler said Wednesday that his organization would make confirmation of judicial nominees a top priority for the first time — providing money and a recently honed ability to stir grass-roots action nationwide.

He said federal judicial-confirmation debates are important to business, particularly because of judges' roles in civil cases.

"There has been too much of a tendency in the past to cast these judgeship battles as a social debate about abortion or gay rights," Engler said. "In fact, there are very few of those cases in contrast to those dealing with the tort system and the rights of individuals and companies."

His comments came on a day Bush promoted limits on medical-malpractice lawsuits and a week after the president announced he would reappoint judges whose confirmation had been blocked by Democrats during his first term.

While several of those nominations received wide attention, they generally have not been the subject of high-priced television and grass-roots lobbying campaigns until now.

Longtime observers said the involvement of well-heeled organizations such as the manufacturers' group could increase pressure on moderate senators whose votes helped block confirmation of 10 of 34 Bush nominees to federal appeals courts in the past two years. Several of those senators will be up for re-election in 2006 and are facing threats from religious conservative leaders if they try to block conservative jurists.

"It's certainly going to up the ante and increase the pressure on vulnerable Democratic senators," said one senior Democratic Senate aide who spoke on condition of anonymity. "I can't think of a similar situation where a group so little identified with such a debate is getting involved at this level in this way."

It was not clear to what extent, if any, Engler was coordinating with administration officials. White House spokeswoman Erin Healy declined to comment, saying only that the administration "welcomes support of the president's judicial nominees."

The manufacturers' initiative came as a surprise to the coalition of civil-rights and abortion-rights groups that have fought Bush's nominees.

Ralph Neas, who directs the liberal People for the American Way, said his organization would gear up to match the new effort, particularly on Supreme Court races. Neas predicted the move would backfire on Engler.

"I believe that a sizable percentage of NAM's membership would be stunned to learn that NAM's leadership has decided to join the right wing's effort to eliminate a constitutional right to privacy, to strong civil-rights protection and a woman's right to reproductive freedom," Neas said.