President Neil L. Rudenstine--traditionally absent from the national political stage--debuted yesterday as the behind-the-scenes director of a prominent display in support of diversity in education.

Although his name never appeared, Rudenstine is widely acknowledged as the author of yesterday's three-quarters-page statement "On the Importance of Diversity in University Admissions" that appeared on page A27 of the national edition of The New York Times.

Issued by the Association of American Universities (AAU), a coalition of premier research institutions, and signed by all 62 of its members, the advertisement is an atypical move for both Rudenstine and the AAU.

"The AAU very seldom adopts statements that take a position this formally," said AAU President Cornelius Pings. "We wanted to get some attention, the attention of policy makers across the country. We wanted to portray our opinion strongly."

But Rudenstine said he could not predict the ultimate effects of the advertisement.

"I think the effect is very hard to judge," Rudenstine said. "There will be many people put off by it and many people who will be encouraged by it."

The advertisement was flanked by a Times article headlined, "62 Top Colleges Endorse Bias In Admissions," which caused controversy among the statement's signatories.

"I think it was unfortunate," Rudenstine said. "I don't think any of the universities thought they were talking about a bias."

After today's Times headline, James H. Rowe III, vice president for government, community and public affairs, said he was irritated by the use of the word "bias" to describe the statement.

Rowe joked, "My next job in life is to be a headline writer."

Recent legislative changes in California and the Supreme Court's refusal to hear Californian and Texan appeals on the issue have placed increasing pressure on universities that use race, gender and ethnicity as part of their admission criteria.

As diversity has become a hot-button topic in higher education, Rudenstine and the other university presidents have discussed it at every AAU meeting for the past three years, Pings said.

"The decision on the California ballot raised the profile of equal opportunity issues," said Laura Freid, executive vice president for external affairs at Brown University. "I think it was a wake-up call for universities across the country to examine them and to express their support for continued attention to diversity in university admissions."

At the October 1996 AAU meeting, Rudenstine suggested that the association consider issuing a public statement on the importance of diversity.

Rudenstine, President of the University of Texas at Austin Robert M. Berdahl and President at Buffalo-State University of New York William R. Greiner drafted the statement for the association. At its April 14 annual meeting, the AAU adopted the state- ment and decided to publish it in The Times.

"I think the rest of the presidents were grateful to [Rudenstine] and the others who were involved in getting this process started ... for their initiative," said Robert K. Durkee, vice president for public affairs at Princeton University.

Though the publication of this statement is Rudenstine's most public action on this issue, Rudenstine has been an advocate of diversity since he was provost at Princeton.

Rudenstine called diversity part of his "portfolio" at Princeton, where he served as dean of students, dean of the college and provost.

"He was always really interested in diversity issues," Durkee said. "In all of the capacities in which he served at Princeton, he was someone who cared deeply about increasing the diversity of the student body and the university in general."

At Harvard, Rudenstine continued his advocacy of diversity, authoring his second President's Report on the University's history of diversity in admissions.

He issued a statement in response to the fifth circuit's holding in Hop-wood v. Texas, a federal appeals case which undermined affirmative action in that state's admissions policies. In the past few months, he has addressed the Massachusetts Historical Society, Princeton University and the American Council on Education on the subject of diversity