Bonn — Warming Soviet-West German relations could be the acid test of allied policy coordination in the wake of Afghanistan. An invitation by Soviet leader Leonid Brezhnev to West German Chancellor Helmut Schmidt for a Moscow summit this summer could either help preserve what is left of East-West detente or drive a wedge of suspicion between the United States and West Germany.
Originally the West German-Soviet summit was to have been a routine return visit after Mr. Brezhnev's trip to Bonn in May 1978. It now takes on an altogether new character in the context of the soured superpower relations after the Soviet invasion of Afghanistan.
When the invitation became known publicly April 16, West German government spokesmen stressed that consultations with allies would precede any decision to accept. They also stressed that a summit that simply repeated known positions would be senseless.
But at this point, Chancellor Schmidt would seem to be already committed to go through with the meeting, given his statement in the Bundestag Jan. 17 that he was ready to meet Mr. Brezhnev as originally planned.
The anomaly of a 1980 summit would be that Chancellor Schmidt would be the only Western leader to see Mr. Brezhnev in the post-Afghan period -- but that as a leader of a regional power he would not be able (nor want) to speak for the West as a whole. The old American suspicions of West German pursuit of its own interests of the expense of Western unity could be revived.
Chancellor Schmidt has been at pains to avert such suspicions; in the post-Afghan period he has repeatedly warned the Soviet Union not to try to drive a wedge between Europe and the US. US-West German solidarity is paramount, he stresses.
The Soviet Union keeps trying by a carrot-and-stick approach to persuade West Germany that its interests are divisible from America's. Press reports of Mr. Brezhnev's letter to Chancellor Schmidt just before the Chancellor's visit to the US last month indicated an implied threat that West Berlin -- and the important East-West German contacts -- are vulnerable to Soviet pressures.
Bonn and East Berlin are acutely aware of this vulnerability and have made every effort to preserve the relatively relaxed East-West German relations despite the current storms in overall East-West relations.
Ranking East German Politburo member and top economic manager Gunter Mittag met Mr. Schmidt in Bonn April 17 as a demonstrative sign of this mutual effort. (The planned meeting this year between Mr. Schmidt and top East German leader Erich Honecker had to be canceled, however.)
The US is also acutely aware of the vulnerability of West Berlin and of East-West German relations, and is sensitive to any hints of possible West German softening toward the Soviet Union because of this.
The kinds of strains that a Soviet-West German summit could thus induce are being given a trial run with Chancellor Schmidt's latest arms-control proposal. On a political stumping trip the weekend of April 11 to 13, Mr. Schmidt tossed out the idea that both East and West declare a moratorium on deployment of middle-range Eurostrategic weapons.
Conservative chancellor candidate Franz-Josef Strauss called the proposal "an open affront to NATO and an unveiled rebuff to the USA."
More discreetly, American NATO officials in Brussels told reporters of their concern that the surprise Schmidt proposal might mean a freeze in current Eurostrategic levels, thus legitimizing present Soviet superiority.
NATO officials also worry that the proposal might be interpreted as a weakening of the NATO commitment last December to produce new middle-range weapons and -- if no progress has been made in European arms-control talks -- deploy them three years from now.
In the flurry of reactions to Chancellor Schmidt's proposal, West GErman government spokesmen defined it as meaning in effect a Soviet moratorium during the three years it would take NATO to ready its new weapons for deployment. As things stand now, the Soviet Union is continuously deploying more SS-20 mobile missiles.