Kremlin may shun arms talks lest it aid a Reagan reelection

''We do not understand the American electoral mechanism, and we know that we don't understand it.'' Those are the words of a high-level Soviet official, explaining why the Kremlin will avoid taking an overt role in the American presidential election campaign.

''But,'' he adds, ''we certainly won't help Reagan during the election.''

That fairly well sums up the position that the Kremlin is expected to take between now and November. This position could change, however, as the campaign unfolds. But for now, the Soviets apparently plan to avoid any moves that might bolster a Reagan candidacy.

One likely outgrowth of that policy: no negotiations on intermediate-range nuclear forces (INF) before Americans go to the polls.

''Before the actual elections, there will hardly be any serious negotiations'' on intermediate-range nuclear forces, a well-informed Soviet official says.

Some opinion polls indicate that American voters' concern over deteriorating East-West relations could emerge as a major campaign issue. Western diplomats stress that the Kremlin would like to exploit this concern.

The Soviet Union broke off INF negotiations in Geneva last November after deployment of new American-supplied NATO missiles began.

All along, officials in the Reagan administration had been predicting the opposite effect - that once deployment began and the Soviets realized the deep resolve of the NATO allies, they would begin in earnest.

Now, a return to negotiations would, in the Soviet view, vindicate the Reagan administration. And that is something the Kremlin most assuredly does not want to do.

Soviet officials were hardly surprised by the Reagan candidacy. For months now, Soviet strategists have been assuming that President Reagan would probably run - and, further, that he has a good chance of winning.

And although the Kremlin would prefer just about anyone else over Reagan, it will likely avoid overt involvement in the election campaign. Thus far, the softer tone of Reagan's remarks about the Soviet Union has failed to sway the Communist Party leadership.

A European diplomat here observes, ''I think the Soviets really aren't particularly sure what the American attitude is toward them.''

Therefore, he says, the natural response is to show that the Kremlin will not necessarily respond when Washington beckons.

Indeed, says the Soviet official, ''We have noticed a little change in the character of the rhetoric. But maybe this is only temporary. . . . Maybe after the election we will again turn into the evil empire.''

For that reason, he says, the Soviet Union will treat the American campaign season as a respite - a chance to concentrate on domestic concerns.

Tackling economic problems is the top priority of the Communist Party leadership, the official says, ''but Reagan is in the way all the time. He diverts our time, our attention, and our money.''

Be that as it may, Western diplomats say the Soviets will be following the election campaign carefully. And these diplomats add that the Soviet aloofness toward the Reagan administration could change abruptly as the campaign unfolds.

''They may decide,'' a high-level Western diplomat says, ''that the President as a candidate may be easier to deal with than as (a second-term) president.''

After all, he notes, the Soviets signed the first Strategic Arms Limitation Treaty during an election year - 1972 - while the US was at loggerheads with the Soviet Union over Vietnam.

Although such a dramatic breakthrough is highly unlikely this election year, the Western diplomat says it is too early to predict what might happen before the year is out.

The Soviet attitude during the election campaign, he says, is ''still an open question.''