Is the Western alliance military muscle more than a match for Soviets?

As Republicans and Democrats exchange opening salvos in a national defense debate that promises to become a fierce artillery duel by the fall, a lobby group here is claiming that "the US and its allies are superior to the Soviet Union in all elements of national power."

The Center for Defense Information (CDI), a moderate, even dovish organization, that supports " a strong defense but opposes excessive expenditures or forces," says there is "an ingrained tendency in our government to overstate Soviet military power and understate US and allied strengths."

Rather than compare the military budgets of the United States and the Soviet Union, declares the CDI's monthly "Defense Monitor," the total military spending of NATO and the Warsaw Pact should be compared. While NATO spent $215 billion in 1979, its rival spent $175 billion, the organization maintains. "Including Chinese military spending with the Western allies gives a combined anti-Soviet military expenditure of $265 billion in 1979," it adds.

Apart from being outspent by NATO and the Chinese, the CDI asserts that WARSAW Pact forces also are outnumbered by them. While the latter can field about 4.8 million men, NATO can muster 5.1 million, it states. When China's 4.4 million are taken into account, the CDI continues, the Warsaw Pact finds itself facing 9.5 million men. Moreover, the quality of NATO artillery, antitank weapons, surface-to-air missiles, helicopters, tactical aircraft, and air launched missiles "exceeds that of the Soviets," it adds.

Indeed, the CDI declares that the alliance's lead in the quantity and quality of antitank weapons and tactical aircraft "perhaps more than compensates for the pact's advantage in the number of tanks."

On the basis of US Defense Secretary Harold Brown's assertion that a rough numerical balance exists between NATO's immediately available nonnuclear forces (including those of France) and the Warsaw Pact in the central region of Europe, the CDI concludes; "This contradicts the widely held view that the Soviets could easily conquer Western Europe in a lightning Blitzkrieg,"

But this conclusion seems to be at variance with the defense secretary's observations on NATO in his annual report to Congress earlier this year. Though Secretary Brown felt the Atlantic Alliance would be "much more nearly in balance" with the Warsaw PAct in Central Europe, provided it modernized and ensured the rapid deployment of reserves, he declared that "even with these reinforcements, NATO will not have as high a level of confidence as I would like of containing a large attack by the [Warsaw] Pact launched with little preparation and warning."

The CDI makes no mention of the oft-repeated assertion by Sen. Sam Nunn (D) of Georgia, that, "NATO has a questionable capacity of sustain a conventional defense of Europe because of continuing severe shortages in available stocks of ammunition and war reserve equipment, a lack of sufficient strategic sealift and airlift resources, and the absence of a reliable manpower mobilization base."

Turning to NATO's naval forces, the CDI finds they occupy a position of "striking" superiority over those of the Warsaw Pact. Where the Soviet Union and its allies can field 235 major surface combatants, NATO can deploy some 400, it maintains. Large NATO warships, it adds, are much more capable of operating on distant patrols than Soviet ships, which have limited range, lack large fuel reserves or nuclear power, and have inadequate accommodation for food and ammunition. but the US Navy is suffering from problems of its own. Adm. Thomas Haywood, chief of naval operations, has said that it is "trying to meet three-ocean requirements with a one-and-a-half ocean navy." Senator Nunn has observed that it is being given more responsibility with fewer ships.

Secretary Brown contends that a fleet of 550 active and reserve ships could meet future demands for sea control and power projection. But some experts estimate the administration would have to spend between $10 billion and $15 billion more in the fiscal years to achieve this.

Elaborating on its theme of America's strength and Soviet weakness, the CDI maintains that the continuing US edge over the Soviet Union in the quality and effectiveness of military technology is borne out by government officials. It cites Harold Brown's recent declaration that "our technology, on balance, continues to surpass theirs by a considerable margin."

But the Kremlin is catching up. "For years we have acknowledged that the Soviet Union held a quantitative lead in military equipment, but believed that our qualitative lead would more than compensate for this," William Perry, undersecretary of defense for research and engineering, reported to Congress earlier this year. "It is time to reexamine that belief and to reject the complacency that went with it."

Examining respective nuclear arsenals, the CDI concludes that the Soviet Union is inferior to its antagonists, possessing 6,000 strategic warheads compared with 9,500 in the US stockpile -- a stockpile that can be supplemented by a further 1,000 if those of the allies and China are included.

But the secretary of defense speaks somberly about parity and even the potential for Soviet strategic advantage in this chilling field of warfare. Indeed, Senator Nunn has bluntly observed: "We are now in a tenuous position that I would characterize as clinging parity. We have lost strategic nuclear superiority."

To buttress its case for American military superiority over the USSR, the Center for Defense Information cites Gen. Maxwell Taylor.

"I am concerned," he said, "that too many people are downgrading our military; that we ought to be standing up and saying we have a great defense so that neither the Soviets nor our people misunderstand that in four hours we can rain more destruction on that country [the Soviet Union] than they experienced in four years of war."

By contrast, Secretary Brown's annual report is prefaced with a remark of Winston churchill: "You cannot ask us to take sides against arithmetic. You cannot ask us to take sides against the obvious facts of the situation."