THE POLITICAL spotlight shining on the now well-under-way 1988 presidential campaign leaves off to one side in the darkness the other 468 federal elections that will be held next year: the contests for Congress. They should not be totally ignored. The candidates for president promise a wide range of policies, from Jack Kemp's gold standard to Jesse Jackson's moratorium on farm foreclosures. But most of those policies would have to be passed by Congress. Voters knew when they reelected Ronald Reagan in 1984 that he would try to cut domestic spending and increase defense. But they also knew that same day when they reelected their mostly Democratic congressmen that Congress would limit domestic cuts and defense increases.

At the moment insiders looking ahead think the next Congress will be pretty much like the one we have now. House strategists for both parties are targeting only a few opposition seats, and not many incumbents seem to be retiring. In 1984 and 1986 the overwhelming majority of House incumbents were reelected. So there is not likely to be much change in the House.

There is more possibility of movement in the Senate, and even an outside chance that the Republicans might regain control, if only because there are fewer contests. Individual strengths and weaknesses, odd-duck local issues and sheer luck can play a role, as they did in enabling first the Republicans in 1980 and then the Democrats in 1986 to win almost all the close races and, against the odds, take control. The Democrats have more seats up this time, 18 to 15, and thus should be more vulnerable, but the political events of the first eight months of this year -- decisions to run or not to run, local issues -- tended to favor the Democrats. Developments of the last week, however -- William Proxmire's retirement, Connie Mack's apparent decision to run in Florida, Rudolf Giuliani's pondering of a candidacy in New York -- may mean fewer absolutely safe Democratic seats and a larger number of serious contests. Over a two-year period the battle for Senate control is a seesaw affair in which you keep trying to guess which side will end up on top.

The race for control of Congress is much less volatile than the race for president, with a far smaller range of possible outcomes. But we should not focus on the presidential race alone. We properly match the candidates -- their competence, character, issue positions -- against one another. But we need to ask also how they would work with the kind of Congress they're likely to get: one that is pretty similar to the one we have now.