The Kremlin has radically scaled down its expectations of what the superpower summit beginning here tomorrow is likely to produce. Anatoly Dobrynin, Soviet ambassador to the United States, said this summer that Moscow expects ``big things'' from this week's meeting.
But, more recently, one Soviet official summed up what Moscow now expects: ``Nothing substantial.''
And the reason, from Moscow's viewpoint, is summed up in two words: ``star wars.''
Moscow has failed to secure a halt to the Reagan administration's plans for a space-based defense system, formally known as the Strategic Defense Initiative (SDI).
The Kremlin says it has become the linchpin upon which progress at the summit hinges. The Kremlin is demanding a virtual halt on research into a space-defense initiative.
``That's the central issue,'' says the Soviet official, ``and they [the Americans] are avoiding it.''
Therefore, the Soviets are likely to block progress on other issues, such as human rights, in order to underline the importance of the SDI issue.
Notably, the Soviets did inform the US State Department that 13 Soviets with family members in the US or claims to American citizenship would be allowed to leave the country. But at least as many more are still being denied permission to leave.
Tass, the official Soviet news agency, says the ``cardinal question of the present'' is ``how to stop the nuclear arms race and turn it back, to prevent it from spreading to . . . outer space.''
And while the Soviets have offered to negotiate deep cuts in the nuclear arsenals of the superpowers, they have linked that offer to a halt to SDI.
Why, suddenly, has ``star wars'' become -- according to the Soviets, at least -- an issue central to US-Soviet relations?
One explanation, offered by US diplomats, is that the Soviets, until recently, have been undertaking their own SDI research unchallenged. Pentagon analysts claim a multimillion dollar research effort has been underway for at least a decade, involving thousands of Soviet scientists.
Now, the Reagan administration is challenging the Soviets on that frontier, bringing US high-technology to bear on the effort. Some analysts say the prospect of American success is worrisome enough for the Kremlin to stake much of its political capital on halting that move.
Soviet officials are unmoved by the argument that an SDI system would be purely defensive, and therefore not a threat to the Soviet Union. They instead refer to SDI as a ``shield'' behind which the US could threaten the Soviet Union with massive destruction if it did not bend to Washington's will.
US officials, however, say it would be foolish for the US to stop SDI research when the Soviets are already conducting it. The secretive Soviet system, they argue, allows research to go on undetected, while the openness of American democracy prevents that from happening in the US. For a time, the Soviets seemed willing to address that concern, hinting that they might accept something less than a total ban on SDI research.
The chief of staff of the Soviet armed forces, Marshal Sergei Akhromeyev, for one, indicated that Moscow might allow fundamental research into space-defense systems, but would demand a halt to any further stages of development -- such as construction of mock-ups or testing of prototypes -- that could be detected by spy satellites.
Ironically, Moscow was proposing to use military satellites already in orbit to prevent the so-called ``militarization of space.''
But it was unwilling to subject itself to the sort of rigorous scrutiny of on-site inspections that might have assuaged US concerns. Nor was it willing to fully explain some actions -- such as the construction of a huge radar complex in the Siberian heartland -- that brought its compliance with existing arms control treaties into question.
In the final weeks before the summit, American analysts say, the Kremlin actually hardened its position, seeming to rule out anything but a complete halt to SDI research.
The Americans argued that was not feasible, impossible to verify, and unwise, because it ruled out the possibility of determining whether the superpowers could rely on defense -- rather than sheer offensive power -- to deter nuclear conflict.
The matter came to a boil during an extraordinary meeting in the Kremlin between Soviet leader Mikhail Gorbachev and US Secretary of State George Shultz.
An unusually combative Gorbachev repeatedly interrupted Mr. Shultz, and stressed that President Reagan was being manipulated by ``anti-Soviet'' elements within his administration. There was no hint that Moscow would be willing to allow any research whatsoever, according to US diplomats. After that, Moscow's rhetoric turned harsher.
Western Kremlin-watchers are puzzled by these developments. Some had concluded that Gorbachev would be searching for some form of compromise with the US, if for no other reason than to avoid the substantial expense of countering the American SDI research effort. Gorbachev himself has indicated he would rather have the funds available for improving the Soviet economy.
With the final analysis, did he dig in his heels?
One theory is that there could have been disagreements in the Soviet leadership over how to respond to SDI, over whether it could be halted through whipping up public opposition, or, failing that, whether to counter it with an offensive missile buildup, or a Soviet SDI.
In the end, according to one Kremlin-watcher, it is possible the only common strategy that Gorbachev and his advisors could agree upon was an essentially negative one -- flatly to oppose SDI, and to make that opposition central to US-Soviet discussions.
Another explanation is that Gorbachev, for reasons known only to him, concluded that President Reagan really was not fully in control of right-wing extremists in his own administration, and that any curbs on SDI were virtually impossible.
One Soviet official, asked if Gorbachev really believed the ``right-wing conspiracy'' view that is sometimes aired in the Soviet press, replied, ``yes, I think so.''
The Soviets point to the continuing disagreement within the Reagan administration over possible concessions here at the summit as proof of their charges. Privately, some Soviet officials are claiming that they were lured into the summit on false pretenses, with the implicit promise that substantial agreements would be possible at Geneva. Now, they say, it is clear that if Washington ever had such intentions, they have been thwarted by administration infighting.
The Soviets are expected to dispute US charges of human rights abuses in the USSR, and to respond with their own charges against the US government. And pointed debate is expected over US and Soviet actions in such trouble spots as Afghanistan and Nicaragua.
To be sure, there are some areas in which the Soviets would still like to see progress. One is in halting the deployment of US medium-range nuclear missiles in Europe. It is unclear, however, whether that is possible without some agreement on SDI.
There are other issues on which the Soviets have a clear interest, such as completion of an exchange agreement covering artistic, scientific, and academic visits, or an agreement opening consulates in New York and Kiev.
But the Soviets call these ``peripheral,'' and a US official admits, ``you don't need to have a President and a [Communist Party] General Secretary meet to sign these kinds of agreements.''
At base the problem is, as before, one of instilling at least a modicum of trust into the superpower relationship -- or, if that proves impossible, setting up mechanisms of verifying the true actions of an untrustworthy partner.
If nothing else, the Geneva may demonstrate the continuing need for this kind of a modus vivendi between the superpowers as the 20th century draws to a close.