As Ronald Reagan prepared to run for president four years ago, his chief domestic issues adviser stirred public controversy with the flat assertion that economic growth and the "explosive increase" in government social spending over the previous decade had "virtually eliminated poverty in the United States."

"The 'War on Poverty' that began in 1964 has been won," Martin Anderson, who later became Reagan's first White House assistant for policy development, declared in 1978, responding to liberals seeking more federal dollars to combat what they argued were persisting problems of poverty.

This fall, as Reagan finds himself sharply criticized for being uncaring and unfair in his deep cuts in federal social programs, the president's counterattack is that government programs of the last generation not only failed to reduce poverty but also brought to a "tragic halt" the economic progress the poor were making before President Johnson's "Great Society" programs.

Reagan's new thesis was expressed in detail in a speech this month to the National Black Republican Council and repeated last week in remarks to black college presidents. He contends that the "binge" in social spending, by "eating away at the underpinnings of the free enterprise system," was responsible for double-digit inflation and high unemployment that had the ironic result of locking the poor in poverty.

Few would argue with Reagan's contention that a healthy economy helps the poor more than do social programs. But whether the programs were failures or the sole cause for serious economic trouble, as he has suggested frequently, are issues about which disagreement has been considerable.

Reagan's thesis ignores any possible impact on the economy of the $141 billion spent for the Vietnam war or skyrocketing oil prices over the last decade. A barrel of Saudi Arabian light crude, for example, cost $1.80 in 1970, $11.51 in 1976 and is $34 today.

"I don't think he Reagan was trying to give a complete economic discourse of the last generation," a White House aide retorted amid discussion of the thesis.

In attacking the Great Society before the black Republicans, Reagan cited only two programs as examples of billions of dollars wasted. They were federal urban renewal and Model Cities, curious choices to defend his cuts since both have been dead at least eight years and urban renewal was created fully 15 years before the Great Society.

The food-stamp program has been one of Reagan's favorite targets because of its tremendous growth in cost. From about $33 million in 1965 when the pilot program served 633,000 persons in scattered communities around the country, its cost grew to $6.5 billion by 1979 when, as a nationwide program, it served 19 million Americans.

Reagan never mentions, however, the conditions that led to such a massive national commitment of resources.

Who remembers, for example, the nation's shock at the finding of physicians sent by the Field Foundation to investigate hunger in America? In 1967, they testified in Congress:

"Wherever we went and wherever we looked, we saw children in significant numbers who were hungry and sick, children for whom hunger is a daily fact of life, and sickness in many forms, an inevitability. The children we saw were more than just malnourished. They were hungry, weak, apathetic. Their lives are being shortened. They are visibly and predictably losing their health, their energy, their spirits. They are suffering from hunger and disease, and directly or indirectly, they are dying from them -- which is exactly what 'starvation' means."

A decade later, another Field team retraced steps taken in 1967 and found "far fewer grossly malnourished people in this country," substantially fewer children with the "swollen stomachs and the dull eyes and poorly healing wounds characteristic of malnutrition." Food stamps and other federal nutrition programs made the difference, they concluded.

Another finding by the 1977 Field team bears partly on one of Reagan's new conclusions -- that the programs had little discernible impact on overall poverty in the nation.

" The change did not appear to be due to an overall improvement in living standards or to a decrease in joblessness . . . ," the Field team said. "In fact, the facts of life for Americans living in poverty, remain as dark or darker than they were 10 years ago."

While some might disagree with Reagan's implicit argument that the nation should not have spent billions to solve social problems, his contention is accurate that the proportion of Americans with cash incomes below the poverty level dropped sharply just before the Great Society, tapered off during the Johnson administration and remained virtually static for several years before beginning to rise in the last couple of years.

Reagan's explanation for this development in his speech to black college presidents last week was that "many well-intentioned programs did nothing but destroy pride and create a feeling of helplessness among those who needed encouragement and hope."

That conclusion is derived simply by looking at gross nationwide statistics that obscure other social forces at work and other problems deserving of attention, although they may not necessarily be solved through government intervention.

The National Advisory Council on Economic Opportunity, in a report to Reagan last September, found dramatic differences, for example, in what happened to blacks in the North and South over the last generation.

"At the end of the 1950s, over two-thirds of the black population in the South was poor; by 1979, only one-third was ," it reported. "But the rate of poverty among northern blacks, after nearly two decades of economic growth and civil rights legislation, has declined only marginally in 20 years. There are 1 million more black poor in the northern and western states today than in 1959."

A study released last week by Reagan's Bureau of the Census found a strong correlation between rates of poverty and the rising phenomenon of female-headed households -- up from 31 to 42 percent for black families over the last decade and from 9 to 12 percent for white families during that same period.

Other researchers found that out-of-wedlock black births were strongly associated with child abuse, truancy, unemployment and juvenile delinquency.

On the other hand, the Great Society years were ones of rapid progress for a new black middle class. Last year, about one-third of all blacks earned more than $20,000. In 1972, fewer than five in 100 earned as much after adjusting for inflation. The Census study suggests that two-parent black families have moved substantially to close the income gap with whites.

The complex task of sorting through the myriad social programs of the last generation to determine what worked and what did not may be left to an unborn generation of graduate students.

Waste, sloth and outright thievery in government-funded programs has been demonstrated and, as Reagan suggests, many well-intentioned programs did not produce intended results.

But the murky picture of those efforts does not lead to Reagan's stark conclusion of failure, that the nation would have been better off if the War on Poverty had never been waged.

Not even Reagan argues that medical and housing programs for the elderly improved their living conditions and appear responsible for longer life expectancy. Increases in government aid for college loans and grants appear closely tied to large increases in the numbers of blacks attending college over the last generation.

The Head Start program, which Reagan has vowed to protect, and federal education aid for the disadvantaged, which he has tried each year to cut, appear related to improvements in achievement levels of primary school pupils.

A recent study by the federally funded education Commission of the States found that the largest relative academic gains in the nation's public schols were made by inner-city or rural area children who were black or lived in the Southeast or had parents who had not graduated from high school.

The gains were much smaller for disadvantaged children in high school and not discernible among high school students.

The bottom line: neither failure nor unqualified success.