Moscow and Washington are winding down their war of words. Two old pros, Andrei Gromyko and Alexander Haig, are taking command and directing the dialogue into more conventional and productive channels. The return of private diplomacy is the good news. The bad news is that what follows is going to be extraordinarily difficult.

The Americans are vehemently denying any progress, lest they be accused of euphoria, or worse--making concessions. But this will pass. For quite different reasons, both sides have an incentive to try to improve relations.

The essential first step was the agreement to reopen the arms control track in the talks that will begin on Nov. 30 on nuclear missiles in the European theater. That the American side will be led by another old pro, Paul Nitze, is also helpful because these talks will quickly stalemate. The first deadlock will be over which weapons to include. The United States must treat this as inevitable and use Soviet interest in SALT as the leverage to break the deadlock. The Soviets may want a separate deal to head off European missile deployments, but even at the cost of Allied anxiety the United States should resist this temptation and maintain a linkage to SALT.

The United States will enter the negotiations on European missiles with a weak hand: the Soviets are building up and we are not. The Europeans are badly divided over whether to proceed with a matching buildup of American missiles. Once the talks turn to MX missiles, B1 bombers and the like, however, the United States has a much stronger hand. It is encouraging that the administration is talking about reviving SALT next spring and perhaps even merging the two sets of negotiations.

The second Haig-Gromkyo agenda item involved the superpower contest outside Europe. It is little wonder that no progress was reported--or expected. But both sides seem to be cautiously feeling their way back toward something like the situation of 1972, when Henry Kissinger tried to define the limits of the relationship in a joint statement of principles. Trying to work out a relationship based on "restraint and reciprocity" and to define what constitutes a "legitimate" interest remains the heart of Soviet-U.S. diplomacy.

The United States should not be too quick to rule out negotiations on a set of principles or code of conduct simply because many of the Reaganites denounced Kissinger's earlier negotiations. Sooner or later, whether in writing or otherwise, some joint principles will have to become the framework for shaping a new relationship, if there is to be one. If the Soviets want to introduce the concept of military stability or equilibrium, so much the better.

Poland clearly was on the agenda of the talks--a "shadow," Haig called it. The secretary was right in warning Gromyko of the serious consequences of Soviet intervention. Poland, however, cannot be settled by Haig and Gromyko. The United States, meanwhile, should not be preoccupied only with the dangers of intervention. There is the possibility that Solidarity will survive. If it does, this will be the most revolutionary change in Europe since the end of the war. It is what all American statesmen have hoped would happen.

Haig ought to give a lot more thought to how this might be encouraged by the United States: for example, could we suspend or cancel the Polish debt so long as the Soviets did not invade and Solidarity operated freely? A peaceful revolution in Poland is worth 50 B1s, for it cannot fail to alter profoundly the power relationships in Europe.

In this connection, one cannot help but note that while Haig and Gromyko were talking, including talking about trade, our European friends were cashing in on a $1 billion sale of compressors for the pipeline that will bring natural gas from the U.S.S.R. to West Europe. There is no use complaining. Europe and the Soviet Union are drawn together by harsh economic facts. But now that the Europeans have been placated with the convening of the Nitze round of negotiations, the United States should use the interval to hammer out some common strategies with its NATO allies, not only on arms control but on Poland and East- West economics.

The last official meeting between Haig and Gromyko must have been in Moscow during Pesident Nixon's last summit in July 1974. At the very end, when the VIPs were milling around the reception area in the Kremlin, President Nixon motioned me over and said, "Get General Haig." Shortly afterward all of us departed. Now Al Haig is starting down another long road which may well end in another summit with another president. One has the feeling that Gromyko will still be there to quarterback the Soviet side.