Why Moscow cool to latest Reagan arms control ideas

Moscow is reacting so far with purposeful chill to new US strategic-arms ideas and to hints of a possible superpower summit. Although they are careful not to close the door on either issue, officials here argue the US moves seem part of a more sophisticated Reagan public-relations approach to superpower questions that is meant to ease any pressure in the United States or West Europe for ''genuine'' concessions to the Kremlin.

An initial response from the Soviet news agency Tass late June 9 to Mr. Reagan's new arms proposals gave a similar impression. Soviet officials profess reluctance to help Mr. Reagan widen what they perceive as ''militaristic'' foreign policies or to help him boost his image as a 1984 candidate for reelection.

Judging by an interview with a senior official here, Moscow seems concerned that Mr. Reagan's announcement of revised strategic-arms proposals could divert attention from parallel talks the Soviets see as more urgent. These deal with medium-range nuclear weapons in Europe and are being held against the background of NATO's intention to start deploying new US missiles in Europe late this year if the talks fail.

Soviet officials suggest they will watch for further details on the strategic-arms front.

Diplomats here note that complete rejection of the Reagan initiative would not do Moscow any good in the ongoing public competition between the superpowers for arms control credibility.

Soviet officials also suggest they want to assess just how far the revised US approach might go toward meeting key Soviet concerns. One of Moscow's major objections to the initial US strategic-arms stand was its sub-limit on land-based nuclear missiles.

Such missiles form the mainstay of the Soviet force and are much more important within the overall Kremlin nuclear force than in the US. American missile strength is more heavily concentrated on submarines.

The new Reagan position envisages a higher sub-limit on land missiles. What is unclear, Soviet officials say, is whether Mr. Reagan's overall stress on curbing Soviet land missiles is seriously altered by the new proposal.

''The Americans talk, for instance, about throw-weight,'' a Soviet source says - the reference being to explosive yield of nuclear arms, an area where large Soviet land missiles give Moscow a lead.

''The throw-weight issue, it seems, may be the Catch-22 in the Reagan proposal . . . another way of seeking unfair unilateral advantage by limiting primarily weapons which make up a larger proportion of our forces than of the Americans.''

Moscow argues ''overall parity'' in strategic arms now exists, with a Soviet lead in land missiles in effect balanced by a US lead in areas like submarine missiles. The Kremlin also wants to limit planned forces of long-range cruise missiles under any accord.

On the summit issue, given increased public attention in Washington recently, the Soviet position may ultimately depend on the timing, agenda, and political context of such a meeting.

Officials here suggest reluctance to aid Reagan in what they see as a bid to shore up his foreign-policy image with a summit. They suggest Washington currently stands to gain more from a summit than do the Soviets.

''Even seriously answering your questions about a summit,'' an official remarked in an interview, ''in effect enhances the false public impression Reagan is making real moves toward better relations.''

''If Reagan really is interested, let's say, in getting accords on trade or arms control or whatever at a summit, he should seriously change current policies that, in our view, seem aimed at anything but this.''