US and third world: time for closer ties?

Is America looking at the real Soviet Union?

Is the USSR ''a nation troubled by internal problems that it can't solve'' - as described in a new report from the Overseas Development Council (ODC) - or a powerful aggressor intent on expansion?

''A critically important foreign policy debate in the United States is taking place at a moment which could well mark a significant turning point in Soviet domestic and international behavior,'' says the ODC's annual summary of US foreign policy and the third world.

The survey suggests that the US should take advantage of declining Soviet fortunes to look more closely at the third world.

The Soviet Union, the report declares, is ''increasingly preoccupied with problems at home and in Eastern Europe. Yet the US foreign policy debate still concerns an aggressive, confident, and expansionist great power determined to use military force when necessary to upset the global balance.''

The United States has ''an almost exclusive and skewed focus'' on Russia as an aggressive threat, to the neglect of other world problems ''of lesser but growing importance,'' the study says.

The survey says the Soviets are doing poorly. ''Contributing to the economic predicament of the Soviet Union are a rapid decline in the growth rate of the labor force, continued production problems and shortages in the agricultural sector, a diminishing supply of petroleum resources, continued technological backwardness, and a host of lesser problems.

''The Soviet Union sustained an annual increase in defense expenditures almost equal to its annual rate of GNP growth (6 to 7 percent) during the 1960s and the first half of the 1970s.''

As economic growth rate falls, the report says, the Soviet leadership will have difficulty cutting back on nondefense areas, in order to retain past levels of growth in military expenditures.

The report sees the Polish crisis as ''the total failure of communist economic planning and management capacities in that country, the near collapse of a national economy, a political crisis of authority of unprecedented dimension, and the appearance of a new working class that is better educated, better trained, urbanized - and profoundly alienated from the post World War II system of communist government.''

The dominant theme of the study is that the US should take the present opportunity to look more closely at the emerging third world. Take El Salvador. The survey recommends ''quiet support and restraint on the part of the United States.''

As another example, the introductory chapter looks at Mexico: ''The difficulties (in Mexico) would seem to be growing in magnitude every year.'' In order to keep up with expanding population, the report estimates, Mexico's economy must grow ''at better than 7 percent in real terms just to employ the 700,000 new entrants into the labor force each year.'' Even this would leave the present 30 percent unemployment rate ''virtually unchanged.''

In a press briefing at the release of the report, ODC chairman Robert S. McNamara called for a US foreign policy that recognizes growing limits on the use of military power in developing countries by the Soviets as well as the US. His message boiled down to an advocacy of more support for the third world with trade, food, and industrial aid.