When the Supreme Court last weighed affirmative action in university admissions a quarter-century ago, American Jewish organizations were in the forefront of the opposition.

Yet as the Supreme Court prepares to revisit the issue in a pair of "reverse discrimination" cases brought by white students against the University of Michigan, leading Jewish organizations have kept a conspicuously low profile, and at least one, the 100,000-member American Jewish Committee, has decided to file a friend-of-the-court brief in support of the university.

"It is imperative to produce educated citizens and professionals who reflect the diversity of our society," Jeffrey Sinensky, the committee's general counsel, said in an interview.

The 50,000-member American Jewish Congress, which joined the American Jewish Committee in a 1977 friend-of-the-court brief supporting Allan Bakke, a white student who was denied admission at the University of California at Davis medical school, is internally divided but has also not ruled out supporting Michigan, at least in part, officials of the organization said.

Of the three major Jewish organizations that filed briefs on behalf of Bakke 25 years ago, only one, the Anti-Defamation League of B'nai B'rith, plans to oppose Michigan's policy unequivocally.

The breakdown in what was once a united front among Jewish civil rights organizations is a reflection of legal and factual differences between the 1977 case and the current ones, as well as the divergent political and ideological agendas of the various organizations.

But it also demonstrates the degree to which many American Jews have gradually decided that admissions policies designed to boost minority enrollment do not threaten their own hard-won foothold in elite colleges and graduate schools.

For many Jews at the time of Regents of the University of California v. Bakke, the concern was that universities would use affirmative action as an excuse to shut out Jews, thus restoring the notorious de facto caps on Jewish enrollment that had only recently been abolished.

But fears of a new "Jewish quota" were not borne out after Bakke, in which the court prohibited quotas but permitted the use of race to achieve diversity, said Alan Dershowitz, a professor of law at Harvard, who assisted the American Jewish Committee on its 1977 brief in Bakke.

"We feared that our hard-earned right to be admitted on the merits would be taken away," he said. "The WASP quotient would be held constant, and the Jews and African Americans would be left to fight over the crumbs. What happened is that Jews have become the WASPs. They are among the dominant groups on campus, in terms of numbers."

Dershowitz said his own opposition to race-conscious admissions has dissipated because his experience teaching law in racially diverse classrooms has convinced him that "affirmative action works."

Another factor in some Jewish leaders' current thinking is the desire to minimize black-Jewish conflict. The Bakke clash was one of many episodes in recent history in which the two groups, allies against segregation, found themselves on different sides. Relations are still sensitive, in part because of differences over Middle East policy.

"Today there is an entire conservative apparatus challenging affirmative action, so some Jews say: Why do we need to be in the middle of it? Why do we need to alienate the black community?" said Marc Stern, general counsel of the American Jewish Congress.

Officials at the American Jewish Committee, generally viewed as having good ties to leading African American organizations, said their position in the Michigan cases is consistent with the position they took in the Bakke case, in which a program that set aside 16 places out of 100 in the medical school's entering class for blacks, Asians, Latinos and Native Americans was at issue.

The committee opposed that as a quota. At Michigan, by contrast, there is no explicit quota. Its undergraduate admissions office awards African Americans, Latinos and Native Americans 20 extra points on a 150-point scale used to rank possible matriculants according to such criteria as grades, test scores, geographic origin and socioeconomic hardships.

Michigan's law school seeks to achieve a "critical mass" of minority students in each first-year class, a number that has ranged from 12 to 20 percent

Sinensky said these policies are consistent with the court's ruling in Bakke: Strict quotas violate the Constitution, but universities may use race as a "plus factor" to foster diversity.

Sinensky said Michigan uses "race as one factor among many others for the purpose of having a diverse student body." Its policy, he said, "is soft enough and amorphous enough . . . there is no fixed or rigid set-aside."

Leaders of the American Jewish Congress, unable to reach a consensus for or against the 20-point undergraduate bonus, have decided to stay out of that case and file a friend-of-the-court brief only in the law school case, Stern said.

He said the brief will agree with the university that the pursuit of diversity can justify certain race-conscious admissions programs. But American Jewish Congress lawyers and other officials are still debating whether the particular "critical mass" approach used at Michigan's law school is constitutional.

Abraham H. Foxman, national director of the Anti-Defamation League, said his organization is sticking to its "principled position" that people should not be judged by skin color, and any use of race in admissions is unconstitutional.

"We feel diversity should be achieved in a racially neutral manner," Foxman said.