EVERY TRUE American loves the familiar story of struggle and triumph by a group from the ethnic underclass - the Irish, the Italians and Jews, the Chinese and, now, the Koreans. So I have discovered another ethnic group whose struggle should be celebrated.

In one generation, these people overcame many of the educational inferiorities imposed on them for centuries. They tripled the number of their young people who graduate from high school. They broke down barriers to higher education and dramatically narrowed the gap with other more fortunate American children. They reached for equality - a ridiculous goal, considering their tragic history as a people - and their progress has been breathtaking.

You may not recognize it, but I am talking about America's native-born black citizens. A few weeks ago, on the 25th anniversary of the Supreme Court's Brown decision, instead of this triumphant message, we heard a chorus of gloom - from black leaders, of all people. Vernon Jordon of the Urban League said, in so many words, that nothing has changed in 25 years. James M. Nabrit, a beacon lawyer who argued one of those landmark cases, denounced the public schools as failures. And so on, with others.

The supposed failure of the public schools is, in fact, a favorite message in newspapers these days, especially in this newspaper, especially the failure of the District of Columbia schools from which so many white citizens have fled.

Personally, I am sick and tired of people beating up on the public schools. I think it is a form of scapegoating, a variation on the old game called "blaming the victim." I suspect some critics use "public schools" as a new codeword for racial slurs, particularly in our largest cities. Most tragically, beating up on public schools serves the interests of those who wish to suppress social change, who want the poor and unwashed to stay in their place, scrubbing floors and shooting dope, tucked out of the way so the rest of us can go on enjoying the more luxurious life of modern America.

At the risk of losing all open-minded readers, I admit my deep personal biases on this subject. I grew up in a family committed to public schools, committed in a way that nobody ever needed to articulate at the dinner table. My mother taught schools, including poor and unwashed children in a city slum. My father served for years on a community school board. My aunt was a teacher. So was my sister. My grandfather struggled up from uneducated poverty, thanks to the "free common schools" of prairie Kansas, and he became a learned high school teacher himself. In the curious manner of these things, my wife's family has a similar profile - an abundance of teachers and school board members.

So I confess - when I hear glib generalizations about the hopelessness of public schools, somewhere deep in my psyche it sounds like they are beating up on our family, and I get angry.

No I hope the public school critics will examine their own biases. How many are motivated, perhaps, by pretentions of class superiority or by racial fears? How many suffer from that social petulance that is really a contempt for children, including their own?

But let's stick to the facts. The evidence, as opposed to someone's rheumy recollections, supports me in this audacious claim: The American public schools are doing a better job today, better than ever before in our national history, of providing universal education for our young people, white, black, brown or whatever.

The facts, for example, describe an educational revolution among blacks. In 1950, only one of every four black children finished high school in America. Imagine: only one of four. The rest dropped out and, with rare exceptions, assumed the menial stations the society reserved for them - stoop labor.

Today, three out of four black children complete high school. Consider the social meaning of that change: In 30 years, the public schools were opened to a hugh underclass of young people. Will anyone argue that this generation, now completing high school, is behind those children who, a generation ago, quit in the 7th or 8th grade? I would like to see the evidence for that.

The District of Columbia schools, notwithstanding their lousy reputation, participated in this great leap forward - more black kids in D.C. are finishing high school, many more are going to college. Just from 1972 to 1977, for instance, the D.C. school system increased its high school graduates by 9 percent - while D.C. high school enrollment was leveling off.

Older black leaders remember fondly the academic excellence of the old Dunbar High School, and they bemoan the present inadequacies of D.C. graduates. They are inclined to forget the old Dunbar was possible only because most black children did not finish high school, much less study Greek and Latin, a generation ago.

The equation is fairly simple, and it applies to public school across America: It's a lot easier to provide excellent education if you are only going to educate relatively few children, particularly if they are students who already do well. If the schools try to educate all children, the job becomes far more difficult. In the last generation, the public schools have tried to do this. They are a long way from what anyone would describe as a rousing success - but they are also far ahead of where they used to be.

This educational upheaval affected white children, too. In 1950, only 56 percent of white children completed high school. Does that shock you? It shouldn't. Poor whites in America have always outnumbered poor blacks. Today, about 85 percent of white children graduate from high school. Are they not better educated than their fathers and mothers who quit school in adolescence, many of them going, like poor blacks, to the bottom rung on the economic ladder? Show me the study proving that .

Anyone looking at such statistics will see, of course, that young blacks did not completely close the educational gap with whites. But their progress is clearly more dramatic than that remaining gap. It translated, with the aid of the civil rights movement and federal money, into an even more remarkable change in higher education - a crude parity, not perfect but certainly a watershed of deep social significance. Black enrollment is now about 13 percent of the college-age population - roughly equivalent to the black share of the overall population. Yes, a good number of these black students are in two-year community colleges, but that is a level most blacks never had a prayer of reaching a generation ago.

Again, it helps to remember what the past was really like - not how some people like to remember it. In 1960, there were 435 blacks in white colleges in the South. Today there are well over 10,000. That represents real social change, which begs the same question: Are these children not better educated than the earlier generation?

At this point, the critics may say, "Yes, but ..." The "but" leads to the muddled question of quality - how much are these children really learning? Aren't some high schools "graduating" illiterates, kids who can't read or write much? Yes, some high school "graduates" are illiterate. Yes, that is a scandal, one that ought to provoke outrage and reform.

But concentrating on this disturbing reality, as if it were "typical," is profoundly misleading. In general, notwithstanding what you think you read in the newspapers, the quality of student performance is as good or better today - repeat, as good or better - than it was a generation ago. Today's children, on the average, do as well or better on achievement tests than their parents did - if their parents were in school at all.

A serious performance gap remains, of course, between black and white, between rich and poor, though the racial differences are narrowing in basic skills. In any case, if you think about it, there will always be "gaps" on achievement scores between different students - unless you can imagine an America in which all children are born with precisely the same brain cells or talents or grow up in identical environments.

Arthur E. Wise of the Rand Corpopration is one of a number of scholars who have studied the array of test results and concluded that the news chiefly is good, not bad. Since the Rand Corporation is not exactly a bleeding-heart think tank, inclined to wishful thinking as I am, Wise's conclusion is valuable:

"The loss of confidence is not the result of a decline in quality; it is the result of a re-emerging conservatism which wants to see the world as worse than it used to be."

One of Wise's favorites is a statewide sampling in Indiana that matched 10th graders of 1976 against 10th graders of 1944 and found the modern group to be superior - though the '76 class obviously included many of those children, white and black, who never reached the 10th grade in 1944.

This demographic change in the public schools - taking more children and taking them further - was also the real reason for most of another celebrated decline, the drop, until last year, in scores on the Scholastic Aptitude Test. The SATs used to be taken by an elite, a relative handful from the better schools, the better families. But then, thanks to egalitarian reforms in education, a much broader cross-section began taking the tests, more racial minorities, more women, more white males from poorer families. This pulls the national "average" down on that test (which measures aptitude, not achievement), just as the D.C. schools lost ground on tests as more affluent whites were replaced in the averages by poorer blacks. But this certainly doesn't mean black children are doing worse than before.

Nevertheless, the new "conservatism" has produced the current "black to basics" hysteria, a trend which is likely to hurt more children than it helps. The "black to basics" formula will make school more boring than it already is, more geared to the safest and lowest common denominator, Dick-and-Jane rote drills. Everybody, by God, is for reading, writing and arithmetic, so let's cram it into their hard little skulls. Most children will hate it. So will most teachers. But public anger must be served, however misguided. A few years hence, the schools no doubt will produce the "back to basics" test scores to show they have solved some problem.

Meanwhile, tests already show that children have been improving on basics, reading, writing and math, white children and black, North and South. The National Assessment reports find the most striking gains among 9-year-old black kids. This is significant because that's where the feds have spent most of the money - on helping younger children from poor families in the early years of schooling.

Indeed, the most serious problems reflected in the national testing is the opposite of rote skills: Students finishing high schools show a declining ability to grasp complex ideas, to draw abstract inferences from diverse information. When you think about the complexity and change in their futures, that's a scary educational problem. But, unfortunately, the critics are stampeding the schools in the other direction.

Who should be blamed for this wrong-headedness? I would start with the school people, who are notoriously inept as defending themselves. They turn and run before every gust of public discontent. They conceal better than they explain.

Or you can blame the newspapers. I do. And I plead guilty myself to participating in that strange value system that finds failure more interesting or important than success.

But the problem with newspapers is not really good news versus bad news. Newspapers, by their nature, are constitutionally opposed to history. They are quite good at taking snapshots of today or yesterday, but that are incapable of looking backward and asking how the snapshot fits into a continuum of events, the complicated story of people changing over time. Today's outrage looks more outrageous if you have forgoten yesterday's.

In any case, as Wise noted, there is an audience out there that wants to hear this message of failure. (Interestingly, though, public opinion surveys indicate that citizens with chilren in the public schools - with their own channel of information independent of the news media - have a much higher opinion of the schools than do others.

The belief in decline is really a public value statement, one that often implies that black children or poor children cannot improve themselves. If education makes no difference, why bother? The children, of course, hear the same message.

Does that make the gloomy Vernon Jordans into an unwitting spokesmen for conservatism? I think it does. It makes someone like the Rev. Jesse Jackson, corny as he sounds, a revolutionary, because Jackson's message to young blacks challenges the "illusion of inevitability," as one social philosopher calls it. The illusion of inevitability is a principal barrier to social injustice because it convinced the downtrodden, no matter how deep their pain, that nothing will improve their low status.

The continuing rage of black leaders, I believe, is aimed at the wrong target. In general, it was not the schools that failed the last generation of black children. It was the rest of society that disappointed the newly educated, that failed to provide the jobs and income that were promised when those young people were urged to stay in school.