Diplomatic clout falters despite superpower strength, report says

In a new annual review, two veteran defense analysts have concluded that both the United States and the Soviet Union are having difficulty translating their increased military strength into diplomatic influence.

One reason for this anomaly is that the two superpowers tend to counter each other, and thus restrict many attempts to expand influence, the two independent analysts say.

But another reason, they say, is quite simply an inability on the part of either power to cope adequately with the developing nations of the world.

Defense analysts Barry M. Blechman and Edward N. Luttwak have argued over such matters for more than a decade. But more than a year ago, they decided to join forces and see what they could agree on.

The aim was to produce a major annual review of the state of US defenses. Their first annual ''International Security Yearbook'' is being published this week on behalf of Georgetown University's Center for Strategic and International Studies (CSIS).

Blechman and Luttwak, both senior fellows at CSIS, have edited the new yearbook with the assistance of Joel S. Wit. They were supported by a bipartisan board of nine former high-ranking US government officials which is chaired by former Defense Secretary James Schlesinger.

Funding for the new study came from both the Carthage and Rockefeller Foundations. CSIS proposed the study as part of an attempt to provide a factual basis for defense debate in contrast with the partisan, or polarized, debate that has characterized much of the discussion on defense issues in recent years.

Blechman is a Democrat and former assistant director of the US Arms Control and Disarmament Agency (ACDA) who has negotiated for the Carter administration with the Soviets over proposals to reduce conventional arms sales. He has been highly critical of the Reagan administration's ''unrealistic'' arms control proposals. Luttwak has worked as a defense consultant to Republican administrations. He has been more supportive of Reagan administration programs than Blechman has.

In their overview of events in the year 1983, the CSIS defense analysts conclude that throughout the world, a ''diffusion of military, political and economic power is a continuing trend which benefits neither the United States nor the Soviet Union. Both seek to contain the process; neither can succeed alone; neither will cooperate with the other to do so. . . .

''Both the United States and the Soviet Union remain unable to cope with the complexities of the third world,'' the analysts say. ''There, internal and external conflicts persist despite the ministrations of one or the other of the great powers. . . .

''Military power is supposed to yield diplomatic leverage, but the correlation was weak during 1983 for both the United States and the USSR,'' the authors say. ''Reciprocal neutralization remained of course the dominant factor.''

In the case of the Soviet Union, they say, ''it seems evident that the past successes of its quest for military preponderance in all adjacent regions have evoked, at least for now, an unfavorable reaction. Throughout the arc of the industrial democracies around the Soviet periphery, all the way from Norway and Sweden to Japan, in many parts of the third world also, there is a greater alertness to resisting Soviet encroachments. . . . ''

But the authors warn that while actions taken during 1983 to contain the Soviets are ''encouraging,'' they may not last long unless backed with concrete measures to strengthen defenses.

In the case of the United States, say the defense analysts, ''the greater diplomatic leverage and prestige that a vigorous rearmament program should yield are still offset by continuing doubts about the stability and consistency of American foreign policy, and about the political, strategic and operational competence of the United States in coping with armed conflict.''

''The decisiveness of US action in Grenada may have reduced these doubts, but the inconclusiveness of American policies in Lebanon and the Middle East more broadly can only have increased them,'' they say.

Despite claims made by President Reagan that the United States has now gone far to restoring its military strength, the authors of the new study said that overall, in 1983, the military balance between the US and its allies on the one hand and the Soviet bloc on the other did not change substantially.

''The defense program of the Reagan administration, as modified by the Congress, is funding future increases in the capabilities of strategic nuclear forces, the size of naval forces, much smaller numerical increases in tactical air power, and no increase at all in the ground forces,'' the authors say.

In Europe, the analysts say, the conventional balance of forces remained relatively stable in 1983. But they argue that overall, Warsaw Pact forces continued to enjoy a quantitative advantage in virtually every major weapon category, with NATO's qualitative lead ''gradually eroding.''

The authors see signs that West European movements opposing the deployment of new American missiles in Europe have peaked. But they also predict major problems for the Western alliance:

''Lingering tensions between the United States and Europe - in trade, fiscal, and monetary policies, in approaches to arms negotiations, and in perceptions of how best to deal with the Soviet threat - can only portend far greater political tensions in the alliance with debilitating military implications in the years to come.''