JUST last month, the US Supreme Court ruled in an unusual case that a divorced woman cannot be stripped of custody of her children because of her remarriage to a man of another race.
Overturning a Florida court, the nation's high tribunal found unanimously that the lower court's ruling - giving the natural father, rather than the mother, custody - was based solely on the race of the child's stepfather. (He is black; the natural father, mother, and child are white.) The Supreme Court said the rationale of the lower court violated the Constitution's guarantee of equal protection of the law.
''A core purpose of the 14th Amendment,'' Chief Justice Warren Burger explained, ''was to do away with all governmentally imposed discrimination based on race.''
This ruling is a culmination of 30 years of continued legal fallout in the field of race discrimination, insists Kenneth Clark. ''It would not have come without (Brown v. Board of Education).''
Dr. Clark, a social psychologist and expert witness for the plaintiffs in the famous school desegregation case of the 1950s, says the high court's historic ruling led, in turn, to a string of legal decisions through the years which pertained not only to education but to other areas and which have branded segregation and racial discrimination as wrong and illegal.
In Brown, the Supreme Court threw out a half-century-old ''separate but equal'' legal philosophy in race relations and paved the way for racial integration of the nation's public schools.
Clark points out, ''Although Brown was addressed solely to education, it had a ripple effect - (effecting) major changes in the pattern of race relations in the United States.''
* Rulings that reduced racism in the fields of public accommodations, transportation, and recreation.
* The stimulus for Martin Luther King's nonviolent civil disobedience movement.
* Antidiscrimination legislation, including the Civil Rights Act of 1964, the Voting Rights Act of 1965, and the Fair Housing Act of 1968.
''More blacks serve in elective office . . . and participate in the process'' since the decision than before, says Clark. He also traces the presidential candidacy of the Rev. Jesse Jackson - and the symbolism it has for blacks - back to the Brown decision.
Of course, the edict of Brown did not immediately bring broad compliance across the land. Significant progress has been made, mainly through the courts, in ending de jure segregation (that imposed by law) in the South. But now, three decades later, the battle is still being fought in Northern cities, where school boards and local officials have dragged their heels in drawing up plans to end de facto segregation (that resulting from housing patterns). And public resistance to busing for racial balance in schools has considerably slowed the integration process.
Despite this, many insist that Brown and successive rulings which mandate that school districts have an ''affirmative obligation'' to achieve desegregation continue to have significant impact. Among them, Charles Vert Willie, a Harvard professor of education and urban studies.
Professor Willie insists that ''school desegregation has been the best thing that has happened to public education (in the US) in this century.'' In his new book, ''School Desegregation Plans that Work,'' he describes approaches in Atlanta, Boston, Milwaukee, and Seattle which, he says, fully meet requirements mandated by the courts.
As do many others, Willie laments how long desegregation of many of the nation's urban schools is taking. For this he blames in part ''Brown 2,'' a follow-up decision involving compliance with the original Brown decision - arguing that the US Supreme Court may have unwittingly slowed the process in 1955 by leaving compliance up to local school boards. ''Most of these plans are made by middle-aged, male whites. And the plaintiffs are young blacks,'' the Harvard educator points out. ''Throughout the US, the fox (school board) has been making plans that favor the fox,'' Willie adds.
What next? Willie wants guidelines for school desegregation to be drawn up, not by predominantly white school officials (as has been the case in the long-embattled Los Angeles school district), but by local blacks.
Further, to counteract ''propaganda'' that school desegregation has failed because of disputes over busing and because of the resentment and violence, Willie would launch a campaign of ''new ideas'' to convince Americans that ''school desegregation has worked. Busing is effective, and - most important - desegregation plans have enhanced all education.'' Any racially homogeneous school in a multiracial, democratic society provides, de facto, an inferior education, he says.
The Willie thesis is that bringing racial balance to the classroom upgrades learning and educational opportunities for whites as well as blacks: He cites recent census statistics: From 90 to 95 percent of all children aged 5 to 17 are in school; two-thirds of the adult population are high school graduates; one-third of the adult population has attended college; one-sixth of the adult population has graduated from college; fewer than one-third of those over 14 are illiterate.
Not only is achievement among both white and black children and adults substantially higher today than it was in 1950 (before Brown), Willie points out , but the disparity in educational opportunity between the races is significantly smaller.
Kenneth Clark says the Brown decision should be required reading for all students - white and black - from junior high school on. ''Rather than argue for prayer in the schools, I would argue to read Brown,'' he adds.