THE DECISION of the Supreme Court sustaining the constitutionality of the male-only draft registration program is hardly surprising. To rule otherwise, the justices would have had to explain away almost years of history and stare down a Congress that sees the draft and registration as social and political, not constitutional, issues.

What is surprising, however, is the regionale with which the court's majority reached its decision. By implication, it sanctioned laws that bar women from participation in combat and authorize the drafting of disproportionate numbers of men and women. Since one of the principal arguments against registration of both men and women was that this would lead inevitably to a draft in which equal numbers of each sex were conscripted, the decision sets the stage for a quite different debate the next time this issue arrises.

The court's rationale, as set out by Justice William H. Rehnquist, goes like this: women are barred by law and military police from combat. The draft Congress had in mind when it approved the 1980 registration program was one designed to produced combat troops. Therefore, Congress could discriminate between men and women because one sex was qualified to do the job it had in mind and the other was not.

Besides being somewhat circular, this argument rests on laws and policies about combat fitness that are presumed, although not ruled, to be constitutional. And it stretches the legislative history of the registration bill a considerable way to come up with a factual underpinning for what the court says Congress had in mind. Our impression is that what Congress was getting ready for was a draft, like those of the past, that produces bodies to fill non-combat as well as combat positions. If that reading of congressional intent is accurate, the explanation of this decision simply evaporates.

Be that as it may, the decision dumps the whole problem of women and the draft back in the congressional lap. By having deferred so completely to the judgment of Congress on what is constitutional in military matters, the court has come close to giving Congress carte blanche in future draft laws. The opinion of Justice Rehnquist clearly implies that Congress could draft all men, by sex, to serve in combat or combat replacement units while drafting one of, say, 10 women to serve in personnel jobs. That will not end all the opposition to the registration and potential draft of females, but it will eliminate the most powerful argument used against universal registration last year.