It is a dangerous mistake, lawyers are told, to guess how Supreme Court justices are going to vote based on their comments during oral arguments. But everybody does it, and yesterday, after the arguments in the draft registration case, supporters of registering women guessed privately that they will lose.

The speculation was based on the questions put to the lawyers -- Solicitor General Wade McCree defending the all-male draft Philadelphia attorney Donald L. Weinberg representing the draft-eligible men who challenged the exclusion of women -- during more than an hour of argument in a packed Supreme Court chamber.

The lawyers restated the arguments in their writtten briefs. McCree said that the court should show "great deference" to the congressional decision last year to include only men in the draft registration program because "waging war and preparing to make war" are areas strictly entrusted to the legistative branch of government.

Congress excluded women, McCree said, because it believed that in time of national emergency, it would need draftees who could be rotated into combat if necessary, and women are not permitted in combat.

Weinberg responded that the case did not involve war or combat, only draft registration, and that the original 1948 congressional decision to exclude women was based on "nothing but stereotypes" about women, "the attitude that men wouldn't want women commanding them." Such a decision, he said, even when military matters are involved, violates the Constitution.

But as is common in oral arguments, the justices did most of the talking, never giving either lawyer more than 30 or 40 seconds to make a point. t

Lawyers on both sides have been confident that Justices Thurgood Marshall and William J. Brennan Jr. will support the inclusion of women. Their comments yesterday seemed to reinforce that confidence.

"Could Congress decide to register only Negroes?" Brennan asked McCree, who is black.

"We would say that would not be legitimate," McCree said.

"How about religion?" Brennan asked. "Could Congress include or exclude people based on religion?"

"That would not be legitimate either," McCree said.

"Only gender" is ligitimate, Brennan said. "Is that what you're saying?"

On the other side, the lawyers have generally thought that Chief Justice Warren E. Burger and Justice William H. Rehnquist would want to defer to Congress' judgment. And their questions yesterday reflected that assumption.

Congress, Weinberg said, acted in 1948 "in an atmosphere permeated by male chauvinism."

"Since when is it the function of the courts to inquire into atmospheres?" Burger asked. "Is that proper?"

Justice Potter Stewart suggested to Weinberg that he was "putting the cart before the horse" by asking that Congress justify its decision excluding women. "I had thought," he said, "that an act of Congress is presumed valid and it's up to you to prove that it is not."

Lewis F. Powell Jr. also questioned whether the lower three-judge federal court that ruled the registration program unconstitutional knew what it was doing. "The [Senate] Armed Services Committee reached an entirely different result and they've been hearing this for years. Do we accept or reject a District Court ruling that is contrary to the findings of the U.S. Congress, and if so, how do we justify that?" he asked.

The hopes of the challengers of the law have been placed on Byron White, John Paul Stevens and Harry A. Blackmun. White seemed at times friendly and at other times unfriendly to the challengers' point of view. Blackmun said nothing.

Stevens was the big disappointment for the challengers. He asked questions reflecting a concern that, contrary to Weinberg's assertions, the registration program could not be judge independently of conscription. If registration did not possibly entail conscription, he said, "nobody would care, would they?"

The distinction is an important one for the challengers, who contend that the case is about civilians, not the military. In the past, the court has allowed the military to breach constitutional safeguards, such as free speech, strictly protected in civilian life. If the draft case is thought to be a military case by the justices, gender distinctions otherwise prohibited might be permitted in a final ruling.