Will the Moscow-Bonn connection help Poland -- and erode NATO?

The German connection may just turn out to be Poland's salvation. If American commentators think -- and the elite Russians who see the red Tass summaries of the Western press then also think -- that Moscow is successfully luring Bonn away from Washington, the Red Army might not have to march. President Brezhnev might be able to display to his colleagues a developing West German gain to justify his inaction on the Polish loss.

The Kremlin might then come to tolerate, however reluctantly, all those heresies it has never before tolerated in a Warsaw Pact ally: a free trade union , a free farmer's union, muzzling of the secret police, grass-roots democracy within the Communist Party, robust public policy debates, pluralism, a blithe ignoring of Soviet ultimatums. And the Americans, preoccupied with West German reliability, might not notice -- and therefore not trumpet -- the czar's singular lack of clothes in Poland.

Americans, in fact, may already be helping the process along by a quirk of domestic politics. By lifting the post-Afghan grain embargo on the Soviet Union -- an act that violates all his be-tough-on-the-Russians precepts -- President Reagan has added to the West German disincentive to a Soviet invasion of Poland. American grain will now help the Soviet Union overcome its worst food shortages in two decades -- if the Red Army stays home.It will be withheld the moment the Red Army occupies Poland.

This scenario, at any rate, is the most optimistic projection in Bonn.

The testing period for this scenario will come between now and the July Polish party congress that is to institutionalize the remarkable Polish reforms of the past seven months. If the Russians are to reverse these reforms, they will have to do so before the Polish party congress -- just as they felt compelled to intervene in Czechoslovakia in 1968 two weeks before that country's scheduled reform party congress.

In recognition of this timetable the West German government is delaying Brezhnev's desired visit to Bonn until fall. That way the visit cannot be misinterpreted as a prior West German carte blanche to any Soviet invasion of Poland --but can only be an after-the-fact reward for nonintervention.

In the view of some analysts, the Soviets still might not invade Poland. Moscow knows the enormous cost it would have to pay, both in Polish resistance and in the new East-West arms race that could follow. Furthermore --a crucial consideration -- there is no immediate danger that Poland's pluralism might spill over into neighboring countries.The Poles are too conspicuously poor to be an attractive model for the more prosperous Czechs and East Germans, and the Polish mentality is too -- well, Western -- to have much resonance among Russians.

The Kremlin realizes how seductive it could be in the long run if Poland gets away with what Czechoslovakia failed to get away with in 1968. The Czechs might come to yearn for a new Prague spring, the Lithuanians for an exuberant visit from the Lithuanian-speaking Polish Pope, the Ukrainians for the autonomy from Moscow of the rival Poles.

But the Kremlin might also figure that squabbling will have to set in at some point among the various Polish groups -- and that the Russians could then manipulate the feuds so as to restore orthodoxy at a much less bloody cost than an invasion of Poland.

In such an evaluation, the West German option might just tip the Kremlin scale in favor of nonintervention.

So far Kremlin has made no definite choice.

If it does decide in the end that it must suppress the Polish heresies at all costs, then the West German connection will clearly be sacrificed. This is apparent in the continued references in the Soviet press to West German revanchist skulduggery in stirring up antisocialist forces in Poland.The West Germans, after all, are the only even partly plausible culprits if a Soviet invasion is to be justified by alleged prior Western interference, in Poland in 1981 as in Czechoslovakia in 1968.

A contrary Soviet decision to court West Germany in a big way would be a tricky policy to execute. It would require real diplomacy with the Bonn government and not just incitement of West German public disquiet about NATO nuclear weapons. It would also require the cooperation of the US in keeping a rigid anti-arms-control posture that Moscow could then cast itself against in European eyes.

A Soviet West German option might not succeed. But it might just be worth the attempt -- certainly for Warsaw, possibl y for Moscow, possibly even for Bonn and Washington.