IT is the season for politics in West Germany. The Social Democrats (SPD), at their party conference, have endorsed Johannes Rau as their candidate to unseat Chancellor Helmut Kohl in January's parliamentary elections. The campaign posters have blossomed everywhere. But politics in Germany tends to be tied up with economics. Of larger ultimate importance than anything said at the conference in Nuremberg is the just-released national economic growth rate: a quite respectable 3.3 percent for the second quarter of 1986 over the second quarter last year.
Germany is struggling with troublesomely high unemployment -- more than 8 percent. But its inflation rate is virtually zero, and it is running a trade surplus to boot.
And so, whatever Mr. Kohl may lack in charisma, he and his Christian Democratic Party look to have a pretty clear shot at another term in office. ``Weiter so, Deutschland'' is their slogan; more of the same, Germany. Hardly ringing oratory. But then, that's not really needed.
Polls have given the Christian Democratic-Free Democratic coalition 51 percent of the vote, a 10-point lead over the Social Democrats.
Kohl certainly has history on his side; the overwhelming tendency over the years has been to return incumbent chancellors to office.
Mr. Rau, minister-president of North Rhine Westphalia, is seen as an immensely nice guy. And the would-be chancellor, who married only four years ago and whose wife is expecting their third child, is probably the most conspicuous example of ``daddy appeal'' in politics since Margaret Trudeau left Pierre in charge of their little ones.
But charisma alone won't make it, and it's not clear that Rau has a dynamic machine behind him. Former Chancellor Helmut Schmidt's admonition in Nuremberg that the Social Democrats really support Rau was greeted with politeness rather than enthusiasm.
Indeed, no longer anchored by the staunchly anticommunist and pro-NATO leadership of former vice-chairman Schmidt, the Social Democrats have been drifting to the left. Rau and Mr. Schmidt represent the moderate part of the SPD spectrum. Under current party chairman Willy Brandt, the SPD has been calling for, among other things, the removal of the Pershing missiles Schmidt fought so hard to have Germany accept, and for a total phase-out of nuclear energy.
This leftward movement has come in response to a push from the right (the need to distinguish themselves from the Christian Democrats) and a pull from the left -- the environmentalist, pacifist Greens; the Greens have claimed several new planks in the SPD platform as signs of their influence and victories for their own party.
It's not at all clear, however, that the electorate is following along on this leftward sally. The Green influence in the debate on a number of issues has been regarded as positive by a broad spectrum of political opinion. But it would be too bad for the Social Democrats if they let the Greens pull them so far to the left that they lost touch with the voters.