FROM the signals and statements emanating from Moscow and Washington, there is something to summit momentum after all. It is quite a change from, say, a year ago. Judging by personnel, tentative bargaining positions, and humanitarian gestures, a structure for improved superpower relations seems less remote.
From the Soviet side, the replacing of Andrei Gromyko with Eduard Shevardnadze as foreign minister was itself a significant step. The relationship between Secretary of State George Shultz and Andrei Gromyko was reportedly not a good one. Gromyko represented the old slate. Certainly communications behind the scenes have improved in recent months.
On the American side, the lineup of the team sent to Moscow this week -- Mr. Shultz, national-security adviser Robert McFarlane, and arms consultant Paul Nitze -- also makes a statement about the emerging cast of Reagan policy. If not itself ensuring a more moderate tone, the delegation's membership at least enhances the prospects of a moderating direction in United States-Soviet relations. President Reagan's moves of late do show a recognition of his party's dual history, embracing moderate and h ard-line factions.
The chief issue of the summit could well be the ABM treaty, and the practical, restrictive interpretation the Reagan administration has made of it. There appears to be room, the administration is suggesting, for discussions and negotiations with the Soviets before going on line with the ambitious Strategic Defense Initiative program the administration has outlined.
A reaffirmation of the ABM treaty would in effect be a ``control'' on SDI, which the Soviets want, while enabling Mr. Reagan to maintain his intention to move ahead with a defensive system. Such an agreement would be consistent with the treaty's distinction between research and development, and with the Reagan style of decisionmaking -- affirming a principle while accepting a compromise to keep progress moving.
On strategic weapons, at least a formula for numbers and percentages could be arrived at in Geneva. It could be left to later negotiations -- and possibly even another summit next year -- to advance such an agreement. But Mr. Reagan's much-desired cut in offensive weapons appears in prospect. On mobile-based nuclear weapons, the administration does not want the Soviet Union to use American missile mobility as an excuse for mobile Soviet deployments. Some in Congress are up set about the future of the MX and the Midgetman project. But mobile Soviet weapons pose problems for an eventual US defensive system.
Human rights benefit from summits. Fewer than 1,000 Soviet Jews have been allowed to leave this year, compared with more than 51,000 in 1979; the exodus of Soviet Armenians has also been halted. Mr. Reagan is expected to raise the issue of emigration with Mikhail Gorbachev, emphasizing that Moscow's allowing a greater exodus is crucial to winning US political support for an arms agreement.
Permission for Yelena Bonner, wife of Soviet dissident Andrei Sakharov, to visit the West for medical treatment is one sign of summit maneuvering -- though this may be small comfort to the Soviet seaman aboard a Soviet grain ship in the Mississippi, whose intentions in twice jumping ship, before being interviewed by US authorities, have become the subject of Ukrainian-American protests.
Even the Middle East peace process is being pulled along in the summit's eddies.
Expectations should not be raised unduly. But current summit preparations do suggest a breaking of ice, if not yet a thaw, in East-West relations.