As War on Poverty cools, question remains: How successful was it?

Buried in statistics that show an overall increase in poverty in the United States lie glimmers of good news.

The proportion of elderly Americans living in poverty dropped from about 30 percent to 15 percent between 1967 and 1981, according to the US Census Bureau.

And the overall poverty rate of 14 percent - 32 million people - just reported for 1981 by the bureau may be overstated by as much as half. If nonmoney assistance from the federal government, such as food stamps and medical payments, is counted as income, the number of people of all ages classified as living in poverty would be reduced by 40 to 50 percent or more, according to various studies.

Does this mean the War on Poverty, which in the mid '60s initiated many of the federal programs aiding the poor, was successful as far as it went? Some analysts argue the War on Poverty and related programs simply sapped the initiative of many to find work. Others say it restored dignity and relieved suffering among millions of Americans.

But both sides agree that it was an expensive ''war.'' Government support programs for individuals have grown from 6.4 percent of the gross national product in 1970 to 10.2 percent in 1980, or from $62 billion to $261 billion, according to the Reagan administration. Much of this money, however, is for social security and medicare, which primarily benefit the middle class.

Now President Reagan, worried about the growth of the these programs (some of which increase automatically with the cost of living), wants to reverse the trend. He is trimming aid to the poor as part of his overall attempt to cut federal spending. This, he hopes, will help cut federal deficits and lead to a rejuvenated economy that will provide the jobs many of the poor need to support themselves.

But, according to Eugene Smolensky, director of the Institute for Research on Poverty at the University of Wisconsin, increases in federal support for the poor - not improvements in the economy - played the ''single most important role in reducing measured poverty.'' This support includes, in addition to social security and medicare, workmen's compensation, programs such as medicaid, Aid to Families with Dependent Children (AFDC), and food stamps.

Mr. Smolensky adds that further cuts in these programs could be expected to increase poverty - in the sense that many of those deprived of them would experience a significant drop in their standard of living. Such cuts are already under way, not in programs serving primarily the middle class - such as social security - but in those serving the poor.

Federal money may have proved useful in reducing poverty rates from the mid- 1960s, but the Reagan adminstration is committed to both vast increases in military spending and further reductions in the US deficits. So the trimming is likely to continue - as is the controversy over the benefits of government programs designed to help the poor.

In his 1981 book ''Wealth and Poverty,'' economist George Gilder writes that the war on poverty simply provided ''a vast expansion of the welfare rolls that halted in its tracks an ongoing improvement in the lives of the poor.'' The result, he continues, was a ''moral blight of dependency,'' which, among other things, attributed to major increases in the number of broken homes among blacks.

(Whites living below the poverty level - $9,287 a year for a family of four in 1981 - outnumbered blacks more than 2 to 1, primarily because whites outnumber blacks in the general population. As a percent of their respective populations, some 34 percent of blacks were classified as poor compared with 11 percent of whites.)

Wilbur Cohen, a former secretary of the Department of Health, Education, and Welfare under President Johnson and an architect of the war on poverty, sees it quite differently. ''I feel the war on poverty had many good, sound elements which could be retained and strengthened,'' he says. He adds that some welfare programs such as AFDC have levels of funding today that are ''atrociously'' low.