Not since the first three decades of this century have the nation's schools been at such a demographic crossroads. Then, the task was the assimilation of millions of children whose parents had flooded into the country from southern and eastern Europe.
Now, almost unnoticed, the nation's attendance map for public schools has again been redrawn. The schools in 23 of the 25 largest cities in the United States have predominantly minority enrollments, with blacks, Hispanics, and Asians the largest groups.
In these same city schools 1 student in 10 was a minority in 1950. In 1960, 1 in 3 was a minority; in 1970 it was 1 in 2; in 1980, it was 7 out of 10. And in 1990, 9 out of 10 students in big-city districts will be minority, according to statistics recently published by the Joint Center for Political Studies.
Education officials say that if public education is to achieve in the final two decades of this century what it did in the first three - helped shepherd millions of young Americans into productive roles in society - the following questions must be answered:
* What must schools in the major urban centers do to give the majority of their students the skills necessary for entering the economic mainstream? These schools have the greatest numbers of children requiring compensatory instruction. They're at the center of intense debate over desegregation, busing , and bilingual education issues. And they're located where the local property-tax base is most heavily burdened.
* Can a proper federal role in providing needed funds, compatible with a tradition of local control over education, be hammered out politically? During the dollar-flush '60s and '70s, the issue of adequate funding for city schools was never resolved.
* Must racially isolated communities see their public schools slip back toward a de facto ''separate but equal'' status, and what are the implications for US democracy if this is allowed to happen?
''For the first time we have a nation whose needs for public schools are very different,'' says Harold Hodgkinson, a senior fellow at the Institute for Educational Leadership in Washington. ''Today's 45-year-old white male worker has to realize his social security check is going to be paid or not paid as a result of the education a black, Hispanic, or Asian student receives in a city school.''
Demographic changes are already sparking debates on the issue of equal educational opportunity for nonwhite students vs. academic excellence in more affluent white suburban districts, education observers say.
Minorities that made up only 10 percent of the public-school population in 1950 are now up to 45 percent in some states. A look at minority public-school enrollment in the following states helps tell the story: New Mexico (57 percent); Mississippi (51.6); Texas (45.9); California (42.9); Arizona (33.7); Maryland (33.5); Florida (32.2); and New York (32).
''If anybody believed benign neglect worked with 10 percent of the population , who is going to believe that 45 percent, as it is in some states, can be neglected,'' says Mr. Hodgkinson.
Beginning with the 1980-81 school year, more than a sixth of all the nation's public-school students have gone to schools in metropolitan New York, Los Angeles, Chicago, Detroit, Philadelphia, and Washington. All of these areas have small white minorities and large numbers of black, Hispanic, or Asian children in their central-city school districts.
''If whole states are either majority minority or close to it,'' says Mary Berry, commissioner on the US Commission of Civil Rights, ''then we must change the record that too often in the past meant quality education is not equated with minority education. The nation is going to have to change this image with a commitment to equity and excellence at the same time.''
''Corporations lament they are spending too much money educating and retraining their new employees on basic skills. They pay for this lack of education twice, at tax time and in training overhead,'' says Cicero Wilson, a resident fellow at the American Enterprise Institute, a conservative think tank in Washington, D.C.
''Unless we improve city schools, how can our corporations compete in the world economy?'' Mr. Wilson asks. ''The current emphasis on improving math and science curriculum must include inner-city schools. They can't be left out of the computer revolution.''
But education officials say it won't be easy to reconcile the different needs of states like Texas, Utah, or Colorado, which have increasing enrollments, with those of New Jersey, New York, and Massachusetts, all still experiencing decline. ''Massachusetts is laying off teachers, while Texas is in the middle of a severe teacher shortage. That makes for divergent policies,'' Hodgkinson says.
Declining enrollment also presents many states with the challenges of a ''graying'' faculty, teacher layoffs, and the need to close yet more schools. Growth states are scrambling to find new classroom space and keep experienced teachers. Some are even experimenting with merit pay to attract scarce math, science, and bilingual teachers.
Also, the Hispanic population is at this point still far more geographically concentrated than the black population. Most Hispanic schoolchildren are in California and Texas. New York, New Mexico, Illinois, Florida, Arizona, and Colorado follow. The 1980 census showed that close to half of the nation's Hispanic population was in 10 metropolitan areas.
In Los Angeles, the Hispanic enrollment has increased from 20 percent in 1968 to 49 percent in 1982. Over the same period, a similar change occurred in Dade County, Fla. (Miami). In Chicago, the proportion of Hispanic students more than doubled, reaching 20 percent, as Hispanic students replaced whites as the second largest group of students after blacks. A similar change took place in Dallas, and the percentage of Hispanic enrollment grew even more, from 13 percent to 28 percent, in Houston, the South's largest city.
Most black students attend schools in just nine states: New York, Texas, Illinois, California, Georgia, Florida, North Carolina, Louisiana, and Michigan.
Many of the major urban centers of California and the Pacific Northwest experienced not only a substantial growth of their Hispanic population but also large increases in the number of Asian children. The San Francisco school district has far more Asian than black, white, or Hispanic students.
% Minority State Enrollment Alabama 33.6 Alaska 28.4 Arizona 33.7 Arkansas 23.5 California 42.9 Colorado 22.1 Connecticut 17.0 Delware 28.8 Florida 32.2 Georgia 34.3 Hawaii 75.2 Idaho 8.2 Illinois 28.6 Indiana 12.0 Iowa 4.1 Kansas 12.7 Kentucky 9.1 Louisiana 43.4 Maine 0.9 Maryland 33.5 Massachusetts 10.7 Michigan 21.3 Minnesota 5.9 Mississippi 51.6 Missouri 14.8 Montana 12.1 Nebraska 10.5 Nevada 18.9 North Carolina 31.9 North Dakota 3.5 New Hampshire 1.3 New Jersey 28.4 New Mexico 57.0 New York 32.0 Ohio 14.7 Oklahoma 20.8 Oregon 8.5 Pennsylvania 14.9 Rhode Island 8.2 South Carolina 43.5 South Dakota 7.9 Tennessee 24.5 Texas 45.9 Utah 7.3 Vermont 1.0 Virginia 27.5 Washington 14.1 West Virginia 4.3 Wisconsin 9.3 Wyoming 7.5 D.C. 96.4
Source: Institute for Educational Leadership, based on 1980 Census