Soviet salesmen with a new pitch

The common ''anti-imperialist front'' of the communist and the developing countries - loudly proclaimed in Moscow and much feared in Washington - has crumbled in one significant area: economic relations.

A good illustration is the sixth United Nations Conference on Trade and Development (UNCTAD) which meets in Belgrade through the month of June. Over the years the Soviet Union has failed in that international forum to turn to its advantage the economic antagonisms between the third world and the West, between the industrialized North and the developing South.

More than that, as Soviet policies at UNCTAD show, Moscow has not been able to undermine the global position of the industrialized West by promoting the ''economic liberation'' of the former colonies. In fact the USSR has abandoned its traditional systemic and confrontational approach to international trade. Instead, it has switched to advocating fair rules, applicable to all countries, as dictated by global interdependence.

UNCTAD was set up in 1964 to redress the operations of the world economy in favor of the less-developed countries (the LDCs). For more than a decade Moscow encouraged and supported the sweeping postcolonial claims of the LDCs against the West. It treated these demands as part of the ''common struggle'' of the communist bloc and the LDCs to replace the ''capitalist-dominated'' world trade system with one based on socialist principles of ''equality and justice.''

When in the early 1970s the developing countries devised the plan for a New International Economic Order (NIEO), Soviet news media hailed it as an attack on the ''positions of imperialism.'' Soviet specialists endorsed this attempt to redistribute resources in favor of the LDCs as a step that would ''weaken the operations of international capital.'' Soviet diplomats strongly supported the NIEO at international forums.

Rhetoric aside, it was obvious that the Soviets fully expected any concessions gained by the LDCs from the West to redound to their own political and economic advantage. Hence Soviet support for NIEO was confidently manipulated in the East-West competition.

For their part, the developing states acknowledged the systemic differentiation between East and West. When formulating proposals, the LDCs distinguished between the communist and the capitalist countries, presenting a different set of demands to each group - with the Soviet bloc getting a separate and much lower bill.

The scenario changed dramatically at the fourth UNCTAD meeting in Nairobi in May 1976. As in the past, the Soviet delegation proposed measures that wove the communist-bloc and the LDC demands into an alternative to the existing world order dominated by the capitalist powers. In the main, the Soviet practice of long-term interstate agreements on production cooperation and compensation to establish fair prices and limit the effects of market forces was presented as the outline of a new, socialist international division of labor.

However, this Soviet version of a reconstructed world economy was not accepted by the developing countries. At Nairobi the LDCs no longer differentiated between East and West, but presented the same demands to all the advanced states, capitalist and socialist alike. Among other things, the USSR, just like the US, was asked to contribute 0.7 percent of its gross national product in economic assistance.

Since Nairobi the NIEO program of the LDCs has lost its appeal for the Russians; likewise, the confrontational approach to international economic relations. Moscow continues to denounce the ''imperialist exploitation'' of the third world - for the record. But the substance of Soviet proposals has undergone change, being now directed at legitimizing the communist bloc's participation in the existing system of international trade.

Already in September 1976, the USSR presented a formal declaration to the UN General Assembly which held that it was possible to ''democratize'' international economic relations even before the ''inherent defects of capitalism'' have been eliminated from the operations of the world economy.

Economic coexistence, instead of confrontation, has become increasingly prominent in both the Soviet line and behavior. For example, last fall Moscow's statement to one of the preparatory meetings for the sixth UNCTAD held that trade subordinated to political goals ''conflicts with the objective trends in the development of world economic activity.'' This past April the Soviet deputy minister of foreign trade, in his comments on the forthcoming session at Belgrade, stated that the USSR had ''always believed . . . that all trade flows are in one way or another interconnected.'' And on that basis he proceeded to argue that it was UNCTAD's mandate to normalize all the trade flows, particularly those between East and West.

The evolution of Soviet policies, so briefly sketched here, offers Western policymakers some food for thought. Obviously Moscow's shift toward a moderate, cooperative stance in international economic relations is self-serving. The removal of all trade discrimination will increase Soviet exchanges with the West. But this is not the only point.

What is significant is that the Russians have become aware of the futility of foreign economic policies based on the anti-imperialist slogans dating back to Lenin. They now recognize the benefits of universally applicable rules of economic behavior that override the counterproductive ideological approach to the third world's problems.

This does not necessarily imply that the USSR will forthwith accept a similar code of conduct on the diplomatic level. But it does indicate that, through a variety of means and stages, ways could be found to demonstrate to Moscow that unilateral support of the developing countries' political grievances cannot be manipulated to the sole advantage of either East or West.