Early last year a little-known social-policy analyst had three minutes, as part of a White House round-table group, to tell President Reagan how to improve American society.

The analyst said that as a "white conservative" the president could talk to middle Americans who were "afraid to visit the big cities" and who have been told they are "at fault for a legacy of slavery and racism." He could let them know there is a "kinship" of "shared values" between a black woman in Detroit working two jobs to get her son through school and a white Iowa farm family that believes in hard work.

Reagan said nothing.

Then in September the analyst, Charles Murray, published "Losing Ground." The book argues that American social and welfare programs, expanded in the "Great Society" of President Lyndon B. Johnson, have not helped poor people but have destroyed the "shared values" that bonded them to middle America: that people having children should get married, that education is important and that work is desirable and rewarding.

Murray's book became the rage among conservative social-policy makers in the White House and throughout Washington. Conservative economist George Gilder wrote that the book was "the most devastating, sustained attack ever made against the welfare state."

Reagan began responding to Murray's words, White House aides said. In his 1985 State of the Union address, he said: "Policies that increase dependency, break up families and destroy self-responsibility are not progressive . . . ."

In his book, Murray called for "scrapping the entire federal welfare and income-support structure for working-aged persons, including AFDC Aid to Families with Dependent Children , Medicaid, Food Stamps, Unemployment Insurance, Worker's Compensation, subsidized housing, disability insurance and the rest."

Such a step "would leave the working-aged person with no recourse whatsoever except the job market, family members, friends and public or private locally funded services," Murray wrote in his chart- and statistic-laden book.

"Losing Ground" shifted the social-policy debate, even among advocates of poverty programs who had been consumed with defending them against budget cuts. Liberals found themselves arguing not how best to use federal dollars to help the poor, but in defense of the idea that government should help the poor.

"Nothing more important than Charles Murray's work has come along in recent years, and his role as a morally credible spokesman for the conservative side of the debate has opened up the dialogue," said Michael Horowitz, counsel to Office of Management and Budget Director David A. Stockman. "Everybody who disagrees with him disagrees respectfully."

But now the debate over the book has abruptly shifted from clamorous approval to riotous criticism. Every fact and figure supporting Murray's thesis that government aid has hurt rather than helped the poor is under attack from a suddenly recharged community of liberal thinkers.

"It's one of the few times liberals have successfully ganged up on a conservative," said Robert Kuttner, author of a social-policy book with conclusions the opposite of Murray's. "Here is somebody who was set up real big and shot down real big. You don't get that every day . . . . Now it's 'Hold him so I can hit him again.' "

Critics contend that Murray, now a senior research fellow at the Manhattan Institute, used false statistical evidence in arguing that rising welfare benefits encouraged the poor to take assistance instead of a job. They said he inflated the evidence of increasing poverty during the 1970s by neglecting to mention that unemployment rose because of the recession of 1973-75.

And they argue that Murray neglects contradictory data showing that the number of people on welfare did not decrease in the late 1970s when the value of welfare benefits, as compared to wages, decreased.

He is also criticized for not crediting social programs with sharply reducing poverty among the elderly; he is accused of improperly using data from three different tests to support his argument that blacks are getting a worse education today, compared with whites, than they did in the 1950s and 1960s.

Probably the most common criticism of Murray's work is that he makes welfare benefits to the poor appear to balloon by using welfare data from only one state, Pennsylvania -- where welfare benefits grew at twice the national rate.

Congress members "cite the book as a dispassionate source of objective data showing that the social programs have failed," economist Robert Greenstein wrote in a New Republic article, "Losing Faith in Losing Ground -- the Intellectual Mugging of the Great Society."

"Yet, the book can be considered neither dispassionate nor objective," Greenstein wrote. "Its distortions and omissions are too serious. 'Losing Ground' is more of a polemical tract than an attempt to examine the complexities and discern the truth about some of the most significant social problems of our time."

Sen. Daniel Patrick Moynihan (D-N.Y.), a moderate who devised welfare changes in the Nixon White House, also criticized Murray's work.

"He may be right," Moynihan said. "But he has not proven anything . . . . Social Security probably reduces savings somewhat; unemployment insurance probably lengthens periods of unemployment somewhat; welfare for children probably leads to more single-parent households somewhat . . . . In that sense, 'Losing Ground' is not at all a break with the past. It merely continues the practice in Washington of making large assertions with no foundations."

Murray has exacerbated the debate with an article in Commentary magazine in which he suggested having poor people live in "residential facilities."

"What would happen," he wrote, "if there were no provision for AFDC, food stamps, Medicaid or housing subsidies, but any mother could, if she chose, live with her child in a residential facility? The facility would provide the standard of living and regulation of a good correctional 'half-way house' (except that the mother would be free to quit the facility at any time) . . . .

"When a young mother, once pregnant, is faced with the choice of raising a child without any outside support whatsoever or living in a residential facility, adoption (and abortion) can reasonably be expected to rise."

The man under increasing fire from the liberal academic community is a 42-year-old from Newton, Iowa, son of a mechanic in the Maytag factory. The father rose to be a company manager. The son went to Harvard for a degree in Russian history. Then it was off to Thailand for five years, two in the Peace Corps; to MIT to study political science, and back to Thailand to do more research on the impact of Peace Corps' work.

When he came home, he went to work for the American Institute for Research (AIR) assessing U.S. social programs. The first assessment, of a program for juvenile deliquents, led to a book, "Beyond Probation," that sparked angry comment from liberals.

"At the time, the prevailing logic said if you send kids to training school you only make them better criminals," he said. "I found that reform schools, secure facilities, are the best you can do for those kids."

After two more studies, Murray tired of doing assessments that were read only by government and private foundations. He left AIR.

He approached the Brookings Institution and the American Enterprise Institute, but they ignored him. The Heritage Foundation offered Murray less than $3,000 to do a paper for its Critical Issues series. It was called "Safety Net and the Truly Needy."

In April 1982, a director of the Manhattan Institute asked Murray if he would like to turn the study into a book. "Losing Ground" was published last September.

"I didn't know what to expect," Murray said. "When there was some reaction I was gratified, but I figured it would be gone by January . . . ."

But now the attacks on him are relentless: "I heard second-hand that after the New Republic pieces people said they had no idea this guy was so tendentious and shoddy. There's nothing I'm on edge about so much as what this is doing to my professional reputation," he said.

Murray views the critics as less than impartial.

"I stepped on an awful lot of toes," he said of them.

"I know the nation is in a conservative mood, but in academia and in this town, what I'm saying remains extremely unpopular . . . .

"My big problem is the scholarly debate right now," he said, moving his fingers over a computerized chess game on the end table next to him. "If you doubt me, let's go talk to people, no clipboards, no multiple choice . . . . I have not heard anybody who has spent a good mount of time in communities of poor people tell me I'm flat wrong. Not one person. Not one social worker. Not one preacher."

In response to claims that he ignored the effects of the economic downturn in the 1970s, which pushed more people into poverty, he argues that rising poverty -- despite increases in welfare -- had started before the recession. The numbers do not bear him out. The poverty rate declined until 1973, just as the recession started, rose in 1975 and then held steady until 1980 when it began to rise again.

As for the criticism that the number of people on welfare did not fall when the value of welfare payments decreased as compared with salaries, Murray said:

"In contrast to the caricature of my argument, I do not see people taking out their calculators and figuring out the value of a welfare check in comparison to a low wage," he said. "On the contrary, I go to great lengths to say that several things contributed indirectly -- changes in welfare, changes in welfare rules . . . , changes in the quality of education, which not only put kids out of school with bad educations but left them unaccustomed to going to the same place every day and working . . . .

"Also, once the value of welfare checks decreased I don't think people got out their calculators and said, 'It's not worth as much anymore so I better behave differently.' By that time patterns of behavior are set."

Did he ignore the benefits of programs to feed pregnant women and hungry children?

"I don't mean that handing out milk is bad . . . ," Murray said. "Our impulse is to say, 'Well, maybe she shouldn't have had the baby, but it sure as hell is not the baby's fault.' We want to do as much as possible for the child.

"Then we have to look at the question: Are we causing more of these children to be born by doing something as innocuous as giving milk?" he added. "That's the fine line to walk, but if you take the package as a whole, how do you add it all up -- helping babies over here while creating a funnel for new problems? Which way is the greater good?

"I don't want to convince people so much as I want to show them the flabby way we think," he said.

Murray does not easily deal with racial issues.

He speaks of "dangerous white liberals" who practice "enormous condescension to blacks." He talks of people who complain that "blacks have not behaved the way we expected them to -- they have so much unemployment, the schools are bad, they're criminals."

Murray warns that there is "tremendous potential for a backlash" and mentions a woman who suggested to him recently that blacks be put in camps.

"It's not so ridiculous when you think about what we've already done," he said. "We drive through Northeast D.C. , but we've got them over there by themselves. It's not a drain on the economy. We have already got the camps started. We just don't call them that yet."

Murray acknowledges that he does not view black or other cultures in the same way he views white culture. He tells of visiting a black elementary school and seeing the "physical play" of black children in the schoolyard. He said that in white schoolyards the wrestling and play fighting would not be allowed.

"So, I watch that and say, 'Gee, that's healthful, a lot of spontaneity.' I might say the white way is sterile . . . . But in terms of my own daughters, I want more restricted schools . . . .

"I don't think we should try to insist to ourselves that their way is just as good as any other way . . . .

He added that "The test of whether 'Losing Ground' is right is still in the future . . . . Social scientists who have purported to test conservative theory regarding poverty and welfare -- including those in 'Losing Ground' -- have seemed determined to cast such theory in terms of stereotypes that are easy to refute."