Ensuring racially diverse college campuses is an issue that has done the improbable: Create a disagreement between President Bush and some of the nation's largest corporations.

Procter & Gamble Co. and Ashland Inc. are two of nearly 50 big companies that today will side with the University of Michigan against the Bush administration.

The White House says the university policy favoring students of color for admission to help diversify the student body is a quota system that discriminates against white students and should be outlawed.

At stake for P&G, Ashland and the other corporations is an interest more fundamental than the politics that have made racial preferences a hot-button political issue for three decades.

They say their prosperity depends on finding a diverse work force, particularly as they are trying to sell to more diverse audiences.

"Many companies have learned, some of them kicking and screaming, that affirmative action works," said Arthur Shriberg, a professor of management at Xavier University who has studied diversity programs. "If government were a business, they'd be out of business. It's just a different world."

P&G historically has avoided political statements in its advertising and civic engagements, making its foray into one of the nation's most emotionally charged issues even more unusual.

Reluctant to offend the administration -- Vice President Cheney was a P&G director before taking office -- company officials declined to elaborate on their position this week before joining other corporations in the "friend of the court" brief with the U.S. Supreme Court.

The companies are not publicly defending the university's specific policy, which awards points to applicants if they are minorities, just as it would for a perfect SAT score.

Verna Williams, a law professor at the University of Cincinnati, said the corporate filing could be significant because it could influence the administration.

"I think it's wonderful corporations are speaking out, because they can make a compelling case of why affirmative action is important to the nation," she said.

E-mail cpeale@enquirer.com