This is a moment of great significance in our nation's history. We stand at the threshold of a decision that will profoundly effect America's higher education system and race relations in general.

When Justice Lewis F. Powell Jr. acknowledged the educational benefits of diversity in the landmark Bakke decision of 1978, he affirmed the common understanding of educators around the country. Following in the long tradition of Brown v. Board of Education and other landmark education cases concerned with race, Bakke quickly became an indelible part of our legal landscape. Universities have relied on that decision for the past quarter-century, and it has worked well in guiding their admissions policies.

Race is among the factors considered by nearly every selective college and university in the country. The importance of diversity has been reflected not just in admissions, but also in financial aid and other outreach and retention programs.

This recognition of the educational benefits of diversity has enriched and strengthened our institutions. Indeed, the diversity of our colleges and universities is one of the major reasons the American system of higher education has been viewed in recent decades as the best in the world.

The educational environment we enjoy does not just happen. It comes in part from well-considered admissions practices designed to foster an atmosphere in which old habits of thought are challenged and new questions continually come at us, forcing us to reexamine what we thought we knew well.

More than 50 years of changes in higher education have taught us that the more diverse the academic environment, the more vigorous its discussions. Our parents' generation learned this from the GI Bill in the 1940s and '50s, when thousands of young men became the first in their families to go to college, and a fresh breeze blew through our campuses.

My own generation witnessed a similar transformation in the 1960s, when thousands of African Americans and other minorities gained new opportunities, closely followed by the women's movement and its wave of new possibilities, aspirations and challenges.

Recognizing the educational benefits of diversity does not mean that we equate a person's race with a particular point of view. There is no substitute for face-to-face interaction among students from different backgrounds. It is the most powerful educational tool we know to break down stereotypes and overcome assumptions. It helps students see commonalities across racial lines and acknowledge differences within racial groups. No book or lecture, no computer simulation or exercise, could convey the message as eloquently.

As a scientist, I have observed personally the enormous impact a growth in diversity has had on the sciences. Just think of what a difference it has made in our understanding of disease. Only as the ranks of leading scientists included more women did we focus on some of the serious health problems facing women, including heart disease and breast cancer. Only as the scientific leadership became more racially and ethnically diverse did we study differences in hypertension, diabetes and cancer survival rates across a diverse population.

Now is not the time to turn back the clock on decades of progress in higher education. There is no effective substitute for the consideration of race as one of many factors in our admissions process.

Other methods do not allow us to recruit a diverse student body while maintaining our consistently high academic standards.

A ruling overturning Bakke could result in the immediate re-segregation of our nation's top universities, both public and private. It also could limit our ability to provide support to minority students through financial aid, mentoring and outreach programs. We have only to look at the impact on flagship campuses in Texas and California to see the effects that such a change in policy would bring.