IN WEST GERMAN politics, the atmosphere is now like an American September before a presidential election. A few days ago, the German election was set, finally and officially, for March 6. The present governing coalition, led by Chancellor Helmut Kohl and his Christian Democrats, is well ahead in the polls, but there is more than the usual uncertainty in this campaign. Americans, watching it from a distance, need to keep two things in mind.

One is that the Soviet pronouncements on the negotiations over medium-range nuclear missiles are directed toward public opinion in Western Europe and, specifically, in West Germany. The election returns will allow the Russians to calibrate the effect of their words, in preparation for the serious negotiations that will begin only after March 6. The Kohl government has said that it stands by the NATO decision to begin installing the missiles in Europe before the end of the year, if there is no agreement in the negotiations. The Social Democratic opposition turns that position around. It wants the negotiations to aim at removing "enough" of the Soviet nuclear rockets, as its platform puts it, to make the introduction of any additional NATO missiles unnecessary. The Russians are now probing to see how many of their own 333 SS20 medium-range missiles might have to be dismantled to meet the German voters' idea of "enough," and turn the country against the introduction of the new NATO weapons.

But the compelling importance of the missile negotiations might make the rest of the world forget there's another issue--one that is hardly less a concern to the Germans. Unemployment is high and rising rapidly. A little over 5 percent a year ago, it now is approaching 9 percent and, by most forecasts, will be around 10 percent by March. It's not clear whether the voters will blame this on the Social Democrats, who were in power until the beginning of October, or on Mr. Kohl and the present government.

This is the second thing to remember--that, as the Germans see it, the election is a great deal more than a simple referendum on NATO's missiles. The two issues, missiles and jobs, are unrelated except in the sense that both reflect deep and longstanding fears of German vulnerability, both military and economic. In this country, the German election campaign willl serve the useful purpose of reminding Americans that their policies often affect voters in Europe as sharply as voters here--and sometimes far more sharply.