Moscow — As seen from here, relations between the Soviet Union and the United States may finally have bottomed out. Some diplomats here cautiously predict that a long, slow upward trend will become evident in coming months.
Western sources say the Soviets have been engaged in a fairly extensive review of relations with the West, one that involved a high-level gathering of Soviet officialdom at a retreat outside Moscow in late December. It is believed that the Soviets are still reassessing their position in light of the deployment of new NATO missiles in Europe.
Soviet sources decline to say how long the review might take. ''But I do not think it will be very long,'' says a member of the Communist Party Central Committee.
In the meantime, the Soviets are holding to a rigid public stance, as evidenced by Soviet Foreign Minister Andrei Gromyko's tough speech in Stockholm last week. But some Western Kremlin-watchers here predict the Soviets will eventually seek an opening with the West - especially as the NATO deployment continues.
''We have come to the conclusion,'' says a West European diplomat, ''that the Soviets do have a real interest in getting Western deployment under control.''
Exactly how long it will take for that to be translated into nuclear-weapons negotiations with the US remains to be seen.
''No one in the West knows,'' the European diplomat continues, ''and we doubt whether the Soviets know themselves.''
But some Western diplomats say a renewal of negotiations is virtually inevitable. Indeed, says one, ''if they want to limit the deployments, they're going to have to negotiate.''
In fact, some diplomatic contact between the US and the Soviet Union is still taking place. The meeting between Mr. Gromyko and Secretary of State George Shultz in Stockholm was the most visible example. But there are others.
For example, the Soviets have apparently expressed a willingness to reconvene talks on reducing conventional forces in Europe, possibly March 15.
Last week, Soviet and American officials met to discuss improving communications links between the White House and the Kremlin, involving the so-called ''hot line'' between the two capitals. And Soviet representatives are due in Washington in late January to discuss the disputed maritime border between the US and the USSR in the Bering Sea.
Such contacts, however, will not prevent the Soviets from making good on many of their threatened countermeasures against the NATO deployments. These will probably be highly visible and well-publicized, such as the recent front-page newspaper reports (in the Soviet Army newspaper, Red Star) that Soviet troops are manning missile sites in East Germany and Czechoslovakia.
And the Soviets will probably station more missiles on submarines off US shores. In the Soviet view, new American-supplied Pershing II and cruise missiles deployed in Western Europe are ''strategic'' nuclear weapons - because they can be fired by the US and hit Soviet territory. Therefore, the Soviets argue that they must deploy new missiles closer to the US to counter this advantage.
''The principle of equidistance is very important to us,'' a Soviet analyst says.
Some Western analysts do not dismiss such statements as rhetoric. Indeed, they say, the Soviets do believe - accurately - that the new NATO missiles have military significance. And that, these diplomats argue, is precisely why the Soviets will want to limit the number of missiles that are deployed on the European land mass within range of Soviet territory.
NATO Secretary General Joseph Luns suggested at a press conference in Geneva last week that the Soviets might decide to negotiate when 200 to 300 new NATO missiles are deployed. Only about 41 of a planned 572 new rockets have been placed in West Germany, Britain, and Italy.
Soviet officials admit they have little enthusiasm for spending the money it will take to match the NATO deployments.
''It will cost our countries millions,'' says a high-level Soviet source, referring to the US and the Soviet Union. ''And it's such a foolish way to spend money.''
Still, another Soviet official says, ''We simply cannot lag behind.''
Some Soviet sources say their own countermeasures to the NATO deployment may spark a major public outcry in the United States. The unspoken corollary is that such an outcry could halt, or at least slow, the deployments.
But Western diplomats here play down the significance of the Soviet countermeasures. The new Soviet missiles deployed in Czechoslovakia and East Germany, they say, do not materially affect the military balance on the European continent. And Soviet submarines already cruise fairly close to US shores, according to American Embassy sources.
Nor, some Western diplomats say, can the Soviets hope to gain much in the future from the propaganda tactics they have relied on in the past - notably, whipping up European fears and stoking the peace movement in NATO countries. Since the deployment began last December, the peace movement in key countries such as West Germany has fallen into disarray. And some analysts think it unlikely the Soviets can revive it.
''The Soviets know that. They know what can be done with propaganda - and what can't be done,'' a European diplomat says.
Further, some Western diplomats say, the Soviets know that refusal to negotiate with the West will eventually be counterproductive, because truculence hardly squares with repeated Soviet claims to be seeking peace and arms reductions.
Eventually, the European diplomat says, the Soviets will be engaged in ''a search for a more reasonable position. It is something which takes time, which will be played gently as far as the deeds are concerned. . . . They will be playing, if you will, hard to get.''
There is, of course, the danger that the Soviets could overact the role.
''We're not going to come running to the Soviets, begging them to come back in,'' says a ranking Western official. But he adds the United States will continue to signal its willingness to negotiate. The hope, he says, is that the Soviets will respond positively.