The Soviet Union appears to be shifting its focus in the superpower arms control negotiations from the Euromissile talks to the strategic arms reduction talks (START).
This is the assessment of some Western military analysts in looking at the contrast between the current deadlock in the Euromissile talks and signs of movement in the latest Soviet offer in START.
In Europe there is a new flurry of interest in the Euromissile talks. It has been spurred by West German revival of last year's tentative ''walk in the woods'' probe. Defense Minister Manfred Worner's and Foreign Minister Hans-Dietrich Genscher's conspicuous public endorsement of the walk in the woods in the past few days would seem to involve more public relations than substance, however.
West Germany is not itself a participant in the superpower talks going on in Geneva. And the negotiating package sketched out a year ago by US negotiator Paul Nitze and Soviet negotiator Yuli Kvitsinsky during their ''walk in the woods'' has been dead ever since it got rejected last fall - formally by Moscow and informally by Washington.
Under these circumstances, West German resurrection of the idea seems to be primarily an attempt to highlight Soviet rejection of that formula. The implication, the government here is arguing to antinuclear demonstrators, is that Soviet rigidity is to blame for the expected failure of the Euromissile talks next fall, and that NATO will then have no choice but to proceed with its planned new missile deployments due to begin in December.
By contrast, the earlier attempt by ex-Chancellor Helmut Schmidt to revive the ''walk in the woods'' two months ago seemed aimed at highlighting American rather than Soviet rejection of the formula. This could have given Schmidt's Social Democrats grounds for rejecting American missile deployments in the fall. At the time, however, it also provided a check on the party's antinuclear left wing, which would have liked to reject the deployments immediately, without even waiting for the next September-to-November session of the Euromissile negotiations to play itself out.
What was and is absolutely unacceptable to the Soviet leadership in the ''walk in the woods'' is the package's exclusion of the independent French and semi-independent British nuclear missiles from the NATO-Warsaw Pact Euromissile balance. The West maintains that these are national deterrents that are not committed to the defense of West Germany and other NATO allies, and that in any case the 144 British and French submarine-based missiles - a further 18 French missiles are land-based - are no match for the Soviet land-based SS-20s.
Lesser Soviet objections to the ''walk in the woods'' package concerned the exclusion of dual-capable (nuclear and conventional) aircraft from the proposed limits and the low ceilings on Euromissiles (75 NATO cruise launchers with 300 warheads vs. 75 Europe-targeted SS-20s with 225 warheads and 90 Asian-targeted SS-20s with 270 warheads).
American Defense Department objections to the package centered on its total ban on new Pershing II ballistic missiles - which for the first time in two decades would put on European soil American missiles capable of striking Soviet territory within minutes.
The Soviet government totally rejected the ''walk in the woods'' formula in Geneva last year. Soviet officials now uniformly deny that there was any such negotiating probe, except perhaps in the head of Paul Nitze. The American government, while not rejecting the probe outright, rejected the ban on Pershing IIs. Some American officials now also express doubts that the probe ever existed except in Nitze's imagination.
This deniability was a risk Nitze and Kvitsinsky knew they were running when they tried to design a comprehensive informal package that might break the negotiating deadlock.
West Germany's attempted revival of the walk in the woods is worth keeping an eye on, however. Delicately, Bonn is suggesting to Washington that it should now endorse the walk in the woods. Since the Soviet Euromissile position has hardened anyway, a number of West German officials believe, the US would run no risk of Soviet acceptance - but it would advertise to European peace movements that it is Moscow rather than Washington that is blocking an arms control agreement.
Twice before, West Germany successfully used similar arguments in persuading the Reagan administration to liberalize its Euromissile position: first in entering negotiations at all in 1981, and second in compromising last spring from the West's opening ''zero option'' (no new NATO deployments in return for destruction of all existing Soviet SS-20s) to seek an ''interim solution'' at any equal level proposed by the Russians.
By contrast to their current inflexible position in the Euromissile (or intermediate nuclear force, INF) talks, the Soviets are finally showing some movement in the START talks. The newest Soviet offer - made in June in Geneva and leaked this month in Washington - fills in details that for a year had been left unspecified in the Soviet position.
Basically, the Soviet bid follows the pattern of the unratified but generally adhered-to SALT II treaty and simply reduces ceilings in that treaty's various categories and subcategories of missiles. Ironically, it is similar to the ''deep cuts'' proposed by the Carter administration that Moscow summarily rejected before compromising on SALT II.
Thus, the newest Soviet position calls for a ceiling of 1,800 strategic launchers (as compared with the ''deep cuts' '' 1,800 and SALT II's 2,250). It sets a subceiling of 1,100 launchers with multiple warheads (MIRV's) including bombers with air-launched cruises (as compared with the ''deep cuts' '' 1,100-1, 200 and SALT II's 1,320). The crucial remaining subcategory of land-based MIRVed missiles is somewhat hazier, but seems to run at about 700 (well above the ''deep cuts' '' 550 but below SALT II's 820).
The latest Soviet proposal, however, unlike Carter's deep cuts, contains no direct limits on the heavy missiles that are fielded only by the Soviets - the 10-warhead SS-18s and the six-warhead SS-19s. A sublimit of 700 would in fact permit retention of all existing Soviet SS-18s and SS-19s.
The Soviet proposal does drop previous demands for severe restrictions on American submarine launchers and on the range of air-launched cruise missiles.
Western analysts' assessment of whether the Soviet offer is ''serious'' or not depends largely on prior assumptions about SALT II. Those who supported SALT II value the continued Soviet acceptance of subceilings for MIRVed launchers (and possibly also for MIRVed land-based launchers). In the SALT II negotiations , Soviet agreement even to the principle of subceilings came reluctantly and late, and was tied to specific counting rules for (primarily American) aircraft with air-launched cruise missiles.
SALT-II advocates thus tend to regard the latest Soviet position as negotiable.
SALT-II opponents, on the other hand, stress that the Soviet position would not remedy at all the main danger of instability arising from the vulnerability of fixed land-based missiles. That is, the Soviet offer would still leave a high ratio of MIRVed land-based missiles and would leave intact the especially threatening SS-18s. The maximum number of American warheads per land-based missile is three and will remain so until the 10-warhead MX is deployed in the late 1980s.
MIRVs risk instability because - on the rule of thumb of two warheads per target - one 10-warhead missile like the SS-18 or the MX could theoretically kill five enemy missiles in a surprise attack, while under the old single-warhead regime one missile could kill only ''half'' an enemy warhead. This ratio increases the advantage of striking first and the risk of waiting to strike second, and makes trigger fingers itchy in any crisis.
For this reason the long-range American aim in arms control - as outlined in the Scowcroft report - is to get back to a stabler single-warhead regime. There have been some private hints that the Soviets share this long-range goal, since a very high percentage of their intercontinental warheads - almost 75 percent - are of the vulnerable land-based variety, while a much lower American percentage - about 25 percent - are land-based and vulnerable.
So far the signs of Soviet interest in a return to a single-warhead regime are not reflected in the specific Soviet negotiating position. Arms controllers argue that the latest Soviet position should be probed seriously, however, to see if it might mean a gradualist arms control agreement now on the way to more far-reaching arms control later.