The Soviet Union's decision to withdraw troops from Afghanistan is being interpreted in two predictable ways.

The first viewpoint, which was swiftly cranked out by a "Pentagon official," is that the Soviet troop movement is little more than an adjustment in the forces being deployed to combat the continuing Afghan resistance. So far, the Pentagon public line is to downplay the seriousness of intent and to regard this action by the U.S.S.R. as a ploy to bolster a faltering Olympic Games. Or, it is regarded as a simple rotation and replacement of forces -- but definitely not an expression of serious purpose by the Soviets to negotiate themselves out of Afghanistan.

The second viewpoint, which will doubtlessly be ridiculed as naive and soft in a game that requires stern imagination, is that this is a serious feeler advanced by the Soviets, that it is another attempt to regain "understanding with the United States and to begin the difficult but necessary job of picking up the pieces of SALT and detente.

This latter interpretation is coming from Western businessmen traveling in recent weeks to the Soviet Union and from serious intelligence analysts in and about Washington.

A Washington journalist reports that sources close to Soviet Ambassador Dobrynin insist that this is a genuine effort to defuse U.S.-Soviet tensions and not a simple gimmick to create a favorable atmosphere before the Olympics.

The sources say that the reported pullout is the start of a serious withdrawal -- that is, if there is reciprocal backing down on the part of the United States along with Pakistan, Iran and other Islamic governments in their support for the Afghan guerrillas.

It would be understandable to reject this view if it came only from the Vance holdovers at the State Department, who are not likely to carry much weight. In fact, it might be logical to reject outright the Western businessmen/State Department reading of the Soviet design, if that point of view had indeed been critically evaluated and found wanting by the best collective intelligence available to the U.S. government.

The problem is that geo-politicians playing war games and campaign hucksters watching polls are more likely to let policy envolve from domestic political considerations. This is not just true of presidential politics, for among the liberal senators presently being challenged, only John Culver (D-Iowa) seems able to maintain a well-reasoned long-range strategic view in the face of right-wing demagogic attacks.

Election-year politics is extremely disturbing to our Western allies. There is a growing attitude among Western governments that they do not want to be forced into a quick choice between a return to the Cold War and maintaining a reasonable measure of detente.

They hold that the Soviets' intent must be tested, that even if the troop movement proves to be a sham, a reciprocal gesture by the United States is necessary before arriving at that one conclusion. Certainly we could make it clear that we have no design to destabilize along Soviet frontiers or to teach the Soviets some sort of "lesson" about Afghanistan. Superpowers can't teach superpowers serious lessons short of global disaster.

East and West need a lessening of tensions between the United States and the U.S.S.R.

If the current Soviet intent is to deceive, that will be confirmation to the non-aligned and the Third World that the Soviet Union is expansionist and not to be trusted. Meanwhile, we will not have lost any military advantage during a testing period.

But why not use every possible diplomatic opportunity to see if the Soviets really want out of their Afghanistan problem?

We should remember that the United States has had some experience at finding a cover to extract itself from a bad situation.