The real importance of the fourth Gorbachev-Reagan summit, United States officials stress, lies in the reestablishment of a pattern of regular top-level superpower contacts. Dramatic policy breakthroughs, they caution, are unlikely. The Soviets are less modest. They agree that regular contacts are important. But they are also looking for movement on a number of key problems. Top-level US-Soviet consultations follow a four-point agenda: arms control, bilateral relations (including trade and culture), humanitarian issues, and regional conflicts. Moscow's main interest, Soviet officials say, is arms control.
Here they single out two main problems: speeding up negotiations to halve the US and Soviet arsenals of strategic nuclear weapons; and getting talks going on the reduction of conventional forces and weapons in Europe. (Related story, Page 18.)
In a burst of summit-induced euphoria, US and Soviet officials predicted after last December's meeting that a strategic-arms agreement could be completed by President Reagan's visit to Moscow. These hopes floundered last month. The two sides, however, say they believe an agreement can be concluded before the end of the Reagan administration.
Hopes for a strategic-arms agreement have put some Soviet officials in an ambiguous position vis-`a-vis the US elections: ``My heart's with the Democrats, but my head's with [George] Bush,'' said one. The Republican candidate, he said, would prove more able to obtain swift ratification of a strategic-arms treaty.
The most frequently mentioned sticking points in strategic arms are: sea-based cruise missile, mobile missile systems, and the Strategic Defense Initiative (SDI, or ``star wars''). The Soviets maintain that sea-based cruise missiles can be effectively verified; Washington maintains they cannot. The Soviets say they expect fewer problems with the issue of mobile missiles. And the issue of star wars seems to have lost its abrasiveness.
``The Soviet Union is no longer raising the question of ceasing work on SDI,'' said Vladimir Chernyshev, a military observer for the official news agency Tass. ``The main thing is that work on SDI does not exceed the bounds of the 1972 interpretation of the Antiballistic Missile Treaty.''
Mr. Chernyshev repeated the Soviet line that certain elements of SDI - excluding weapons or parts of weapons - could be tested in space.
Soviet officials say that conventional weapons will receive a lot of attention at the summit. They hope that the two leaders can agree to put conventional-weapons negotiations on the fast track. (Talks between NATO and the Warsaw Pact started in 1973).
At a press conference Thursday Sergei Akhromeyev, armed forces chief of staff, dismissed reports that Mr. Gorbachev might announce a partial withdrawal of Soviet troops from Eastern Europe. There has been speculation that such a move would help spark conventional-force discussions.
Speaking immediately after the press conference, Tass' Chernyshev sounded a slightly different note. Previous Soviet gestures such as a nuclear-test moratorium had not produced results, he noted. ``But now a lot has changed,'' he said, saying that such a gesture ``might work, or at least would demonstrate our sincere readiness for deep [force] cuts.''
Moscow is also eager to see the final ceremonial exchange of the ratified treaty on intermediate nuclear forces. The verification procedures in the treaty, signed in Washington last december, could help break deadlocks in other areas of disarmament, the Soviets say. These include chemical weapons and conventional weapons.
Both sides call for cooperation on regional issues - conflicts as diverse as the Middle East, the Iran-Iraq war, Nicaragua, southern Africa, and Cambodia. But substantial disagreements and mutual suspicion remain.
On the Middle East, Washington and Moscow both speak of the need for a major peace conference. One Soviet official, however, complains that Washington wants a ``talk show'' on the problem, while Moscow wants a conference that will produce a Middle East settlement. (The fact that at least one Israeli journalist is in Moscow covering the summit underlines Moscow's newly accommodating attitude to Israel).
Washington accuses the Soviets of vagueness over the Iran-Iraq war. The Soviets have agreed in principle for further UN action to enforce a cease-fire, but, US officials say, have done little to help one materialize.
The Soviets cite last March's Geneva agreement on Afghanistan as an example of how the two superpowers can cooperate in resolving regional conflicts. But they remain suspicious of US intentions in Afghanistan.
Speaking at a presummit press conference Wednesday, First Deputy Foreign Minister Yuli Vorontsov said the US had approached Iran late last month with a proposal to continue military supplies to Afghan guerrillas through an unnamed third country. Such a proposal would be in direct contravention of the Geneva agreement.
Both sides are making conciliatory noises on human rights. During a press conference Thursday, a group of senior Soviet officials sidestepped the opportunity to denounce Reagan's planned meeting with dissidents and Jewish refusedniks. And while they pay lip service to the need to discuss improved trade and other bilateral relations, Soviet officials concede that they do not expect these to be major discussion points.
As so often in the past, Moscow appears to believe that everything will flow from arms control.