Twelve Democratic senators urged the Supreme Court yesterday to uphold the University of Michigan's affirmative action admissions policies when it considers two politically charged cases in April challenging the programs that favor minority applicants.

On orders from President Bush, the Justice Department last month filed written briefs urging the high court to strike down the programs as unconstitutional and arguing that race-neutral alternatives are available.

The Democrats said in their brief that universities should be allowed to consider race as a factor in the admissions process in order to foster racial and ethnic diversity in their student bodies.

"Diversity in education is not a waste of time," Senate Minority Leader Thomas A. Daschle (S.D.) said in a statement. "For 20 years it has been a national goal, and it should remain so."

Joining Daschle in the brief were Sens. Edward M. Kennedy and John F. Kerry of Massachusetts, Sens. Charles E. Schumer and Hillary Rodham Clinton of New York, Sens. Jon S. Corzine and Frank Lautenberg of New Jersey, Illinois Sen. Richard J. Durbin, Wisconsin Sen. Russell Feingold, Louisiana Sen. Mary Landrieu, Michigan Sen. Debbie Stabenow and North Carolina Sen. John Edwards.

"President Bush's position in the University of Michigan cases is divisive," Kennedy said in a statement. "The Bush administration is undermining one of the most important tools for promoting equal opportunity."

In its historic 1978 Bakke v. Board of Regents decision, a sharply divided Supreme Court struck down racial quotas in school admissions but allowed race to be used in deciding which students would be accepted.

In the Michigan cases, the court will revisit the issue for the first time since the 1978 ruling.

It will hear arguments on April 1, with a decision expected by the end of June.