THE announcement that Secretary of State George Shultz and Soviet Foreign Minister Andrei Gromyko will meet in January to discuss President Reagan's proposal for ''umbrella'' arms talks is heartening. But the prospects for a fruitful Shultz-Gromyko meeting may depend largely on what the administration wants to include under the umbrella.
Press reports suggest that ''umbrella talks'' is a phrase and not a well-defined proposal. One Reagan official told the Washington Post, ''We're as confused about it as they (the Soviets) are. Nobody knows what it means.''
In theory at least, an umbrella approach - the merging of several negotiations previously conducted separately - could be useful. The search for trade-offs between United States and Soviet forces might be enhanced by considering each side's forces as a single package. Indeed many observers suggested last year that the START talks on long-range weapons be combined with the INF talks on missiles in Europe.
Such an approach - renewing dormant negotiations under a new rubric and with a hint of new US flexibility - might allow the Soviet Union to return to the bargaining table without losing face after its failure to halt the deployment of US cruise and Pershing II missiles in Europe. In particular, US willingness to discuss an antisatellite-weapons treaty should be enough to prompt the Soviets to reopen discussions on nuclear forces.
But a comment by White House spokesman Larry Speakes suggests that at least some Reagan officials want to put a more controversial item under the umbrella: ''We think it would be timely to discuss the relationship between offensive and defense systems. . . .'' In other words, these officials want to bring ''star wars,'' the US plan to develop antiballistic missiles (ABMs), into the discussion. Few ideas would be more harmful to the cause of arms reduction.
In fact, umbrella talks on offenses and defenses - nuclear missiles and ABMs - took place 15 years ago in SALT I. A common definition of the relationship between the two types of weapons was reached: Increases in defenses by one side would provoke increases in offenses by the other; a mutual ban on nationwide ABM systems was necessary before limits and reductions could be achieved. Thus the final 1972 SALT I agreement included both an ABM treaty, banning nationwide deployment, and an interim agreement on long-range nuclear weaponry.
In the view of most advocates of arms control, the ABM issue was settled. The focus shifted from defining the offense-defense relationship to restraining the offensive arsenals. While the 1979 SALT II Treaty did not reduce the stockpiles or halt the arms competition, it did place restraints on Soviet forces and thus enhanced US security.
That is why the Reagan administration, though initially critical of SALT II, has pledged not to undercut its provision so long as the Soviet Union shows equal restraint. That is why Congress recently urged the President to continue to adhere to this policy.
Given a willingness on both sides to bargain in good faith, additional verifiable agreements to restrain and reduce nuclear weapons could be reached. But interjecting star wars into the equation can only put us back to Square 1, back to the days before SALT, back to the days of unrestrained arms racing.
Some might argue that the administration can use star wars as a bargaining chip, to force Soviet concessions in other weaponry. But there is no reason to believe that another display of US technological mastery will lead to Soviet capitulation. Previous displays - such as those of MIRVs and long-range cruise missiles - only prompted the Soviets to match our efforts.
In fact, like earlier weapons touted as bargaining chips, star wars is fast acquiring momentum and constituencies in the Pentagon and the defense industry.
But some officials still see a role for star wars in arms control. Lt. Gen. James Abrahamson, manager of the star wars effort, recently told the Monitor, ''It (star wars) opens up a whole new regime for leverage with negotiations. We may even do some trading. We might say, 'OK, we won't put something up for three years if you take out 500 warheads.' ''
General Abrahamson may believe he can redefine the offense-defense relationship, but Moscow has already made clear that it is sticking to the SALT I definition. If we told the Kremlin that we were ready to deploy ABM systems but would hold off for three years, they would not agree to dismantle 500 warheads. They would add to their missile force to ensure that it could penetrate our projected ABM system. They would also accelerate their own ABM efforts, which we would be forced to counter with new missiles of our own. Some arms control.
Abrahamson's ill-founded analysis has been undercut by Defense Secretary Caspar Weinberger, who recently said of star wars, ''It's not a bargaining chip. If we can get it, we would want to have it and we're working very hard to get it. It's not a chimerical thing out there on the margins to try to influence them to make reductions in offensive arms.'' Weinberger has made himself clear: arms reduction and star wars do not go together.
If the administration wants Secretary Shultz to make progress in Geneva, it will have to reconsider its advocacy of star wars. Umbrella talks could be an effective vehicle for breaking the deadlock in arms control but not if the US aim in such talks is to revive the threat of ABM deployment. The Soviets are unlikely to trade away a single weapon so long as that prospect hangs in the air.