Bonn — The final verbal sparring has started as the countdown to the December deployment of NATO's new Euromissiles approaches. But the final serious negotiating has yet to get under way.
This is the assessment of Western observers following Soviet leader Yuri Andropov's latest offer to scrap a ''considerable number'' of SS-20 missiles in connection with any Euromissile arms control deal.
On Aug. 26 Andropov told Pravda that the Soviet Union is prepared to ''liquidate'' enough SS-20s to bring Soviet intermediate-range nuclear forces (INF) in Europe down to a number equal to British and French nuclear missiles.
Previous public or semipublic Soviet offers have been ambiguous and contradictory in proposing ''reductions'' in weapons. It has generally been left vague whether reductions would entail actual destruction of these missiles or just their transfer to Siberia. Simple relocation would be unacceptable to the West both because that would increase the Soviet threat to Japan and China, and because the mobile SS-20 could easily be moved back in time of crisis to retarget Europe.
A State Department spokesman, commenting on the Andropov proposal, said that if the Soviet Union now confirms this offer at the negotiating table, this would be a positive sign. He added, however, that it would still leave unresolved the issue of French and British missiles.
The West is expressing such guarded interest in the Pravda statement because (1)it would be bad public relations to dismiss it out of hand, and (2)it is the firmest promise yet by any Soviet leader to destroy and not just redeploy any excess SS-20s.
The last indication that Moscow might physically dismantle excess SS-20s was given by Soviet officials to Social Democratic chancellor candidate Hans-Jochen Vogel last January during the West German election campaign. Mr. Vogel understood his Moscow hosts to have said at the time that some portion of European SS-20s could be destroyed and some portion moved eastward, with the ratios to be worked out in negotiations.
Soviet Foreign Minister Andrei Gromyko gave short shrift to such an interpretation of Soviet intentions during his subsequent visit to Bonn, however , and Central Committee member Vadim Zagladin later denied that the Soviets contemplated scrapping any missiles.
Soviet failure to pledge destruction of missiles at the formal talks in Geneva has also aroused Western suspicions: Is this periodic informal Soviet offer - Western diplomats ask - anything more than a propaganda ploy for West European, especially West German, consumption?
If in fact the Soviet Union does offer to dismantle missiles at the Geneva talks, this willingness could make the implementation of any arms control deal feasible.
It would still leave the two sides far apart, however, on the substance of an agreement. As this year's final US-Soviet Euromissile negotiating session approaches (Sept. 6 to Nov. 15), the West is demanding equal numbers of NATO INF warheads and Soviet INF warheads in both Europe and Asia. It exempts from the balance the independent French and semi-independent British nuclear missiles - and also both NATO and Warsaw Pact nuclear-capable aircraft.
If no arms control deal is reached by the end of this year, NATO has announced, it will deploy 572 new American single-warhead INF missiles in five European countries over the next five years. NATO regards these future 572 warheads as a response to the more than 1,080 already existing Soviet warheads on the more than 360 triple-warhead SS-20s that the Soviets have deployed since 1977.
For its part, Moscow is demanding a number of Soviet INF warheads equal to British and French nuclear warheads. This would permit no American deployments of new Euromissiles at all.