Soviet President Leonid Brezhnev, again out of public sight for the time being, may well be busy gift-wrapping a policy package for an expected West German visitor.
Diplomats here say that if the package proves sufficienty alluring -- and if tension in Poland doesn't prompt a Soviet intervention that would render the whole exercise academic -- Ronald Reagan could face mounting difficulties in selling a hard line on the Soviets to key West European allies.
President Reagan could also come under heightened West European pressure to take a more amicable look at Mr. Brezhnev's recent suggestion of fresh superpower arms talks.
The scheduled guest is West German Foreign Minister Hans-Dietrich Genscher, and his visit should afford the clearest view yet of precisely what Mr. Brezhnev meant by the arms talks proposal and other suggestions made in a Feb. 23 speech on reviving East-West detente.
Diplomats here suggest the visit, scheduled to begin April 2, may also serve to highlight an important element in the Soviets' overall strategy toward the West: to skirt Mr. Reagan's evident resistance to an early rapprochement with Moscow by playing to his European partners.
A prominent official Soviet policy expert, speaking privately to this reporter, denied suggestions that Moscow was seeking to split the Western alliance outright.
"We are not naive," he said.
He said the Soviet Union had no doubt that the central element in "world war or peace" was relations between Moscow and Washington. That, he said, was the top Soviet policy priority.
But he acknowledged evident "contradic tions between Western Europe and the United States. . . We can use these contradictions, as does any state.
"If we take a concrete situation . . . and America says, 'no,' while West Europe says, 'yes,' of course we will deal with West Europe," he said.
This, European and other diplomats here suggest, is where Mr. Brezhnev's gift-wrapping could come in.
Oddly enough, prior to Mr. Genscher's visit, the Soviets have been taking an almost truculent public approach to the foreign minister and the Bonn government in general.
The official press has been scolding Mr. Genscher and the German government for not accepting all of Mr. Brezhnev's proposals --sive" by the Soviet newspaper Pravda March 22 -- with no questions asked. Bonn has been accused of "surrender" to Washington.
The Soviets have simultaneously stressed "differences" between the West Germans and Americans, particularly on the issue of a Soviet-US summit, which Mr. Reagan is in no hurry to convene. Also emphasized in the official news media here is political pressure on West German Chancellor Helmut Schmidt from more dovish circles at home.
"They are trying to put Genshcher on the defensive," said a senior European diplomat.
But most European analysts expect that Kremlin leaders won't waste too much time shouting at Mr. Genscher once his private talks here begin.
Instead, the Soviets are expected to offer what they see as a policy concession, intended to underscore for the West the seriousness of MR. Brezhnev's detente proposals.
Among possible policy presents mentioned by European analysts here are the following:
* A promise of talks on eventual reduction of the number of Soviet SS-20 medium-range nuclear missiles now pointed at Western Europe. Mr. Brezhnev made a similar proposal in late 1979.
* A relatively moderate reading of Mr. Brezhnev's conditional offer, in the Feb. 23 speech, to extend military "confidence" measures, such as advance notice of miltiary maneuvers, to the entire European part of the Soviet Union.
Mr. Brezhnev said the West must extend its own confidence zone accordingly, which many diplomats here took to mean inclusion of parts of the US mainland. The Soviet leader could conceivably tell Mr. Genscher the intended reference was , instead, to parts of the Atlantic Ocean.
* A promise to "recount" the number of Soviet troops now in Europe, with relevance to the continuing East-West talks on mutual force reduction there. The US has long charged Moscow is inflating the figure, to gain an edge in any eventual cutback.
There are other possibilities. Nor can the eventuality be excluded that Mr. Genscher will be handed a "concession," in the Soviet lexicon, that looks like nothing of the sort to the West. Finally, the visitor could be sent home with nothing at all, although this seems a minority view among Moscow diplomats.
Mr. Genscher's visit is seen as especially important to the Soviets. He will be the first senior Western government envoy to meet Soviet leaders since Reagan took office.
The visit comes at a time when the Kremlin seems concerned that another turn of the arms race could further strain the troubled Soviet economy. Moscow is also looking for Western European cooperation in a huge pipeline project designed to get Siberian natural gas to the western Soviet Union, and to hard-currency customers like West Germany, France, and Italy.
The visit also comes shortly before several important points on the calendar of East-West relations, including an expected session of NATO's nuclear planni ng group.