The Supreme Court heard debate on the sensitive issue of preventive detention yesterday, amid signs that the justices would just as soon avoid the whole controversy this year.

At issue is an amendment to Nebraska's constitution denying pretrial bail to those accused of forcible rape when the evidence against them is great.

The amendment, one of the strongest anticrime measures enacted by a state, was passed in 1979 after a brutal rape-murder was committed by a man released on bail after pleading guilty to a previous sexual assault. An appellate court declared the amendment unconstitutional.

The question of whether the U.S. Constitution guarantees a right to bail is central to a current debate in Congress and many states on whether judges may lock up defendants deemed "dangerous" while they await trial.

But in oral arguments yesterday, some justices questioned both sides closely in search of procedural defects or legal peculiarities that would either make a substantive ruling unnecessary or isolate any ruling from the general debate over preventive detention.

If the court does "dump the case," as one of the participating lawyers put it, the Nebraska bail case would join an increasing number of sensitive cases dropped by the court in the past two years for procedural reasons.

In theory, the court is supposed to avoid major constitutional judgments if possible. In practice, a number of other factors can come into play, such as the court's inability to render a clear opinion on the merits of a case, or a desire on the part of one side of an issue to avoid a precedent harmful to its interests.

Terry R. Schaaf, assistant Nebraska attorney general, defended his state's law by saying that the Eighth Amendment to the U.S. Constitution only prohibits "excessive bail"--it does not say that bail must be granted, only that when it is allowed, it may not be too high.

Bennett G. Hornstein, the Omaha public defender who challenged the law, said bail may be denied only in cases punishable by the death penalty, where the sentence is so potentially severe that the incentive to flee before trial is irresistible.

Unlike most bail laws, Nebraska's does not take into account the defendant's likelihood of showing up for trial, nor does it require a finding of "future dangerousness" to the community.

Schaaf explained that under the amendment, a defendant loses the right to bail when a judge determines that the proof or presumption of guilt is great.

"And that's the end of it?" asked Justice Byron R. White.

"Yes," said Schaaf. "The judge need not articulate his reasons for denying" the bail.

The justices then focused on ways of disposing of the case, James M. Murphy vs. Eugene L. Hunt, without ruling on the merits or creating any major precedents.

During the bail hearing for Hunt, a now-convicted rapist who was denied bail before trial and is represented in this case by Hornstein, the public defender agreed with the prosecutor that the evidence against Hunt was sufficient to make him subject to the law. Thus bail was denied without argument.

Justices John Paul Stevens, William H. Rehnquist and Sandra Day O'Connor wondered whether that agreement--called a "stipulation"--didn't remove a critical controversy from the case. "You've rushed to get us a test case," said Stevens. "We don't know if we've got a live case here."

Other justices questioned whether Hunt, because of his conviction, has any stake in a Supreme Court ruling on denial of bail. If the justices feel he has nothing at stake, they can hold that the case is "moot."

The arguments included an awkward moment for Chief Justice Warren E. Burger, when Nebraska's lawyer, in addition to citing various cases in support of his position, cited a speech delivered by Burger lauding the concept of preventive detention. Burger gave the speech last year before the American Bar Association and was criticized by liberals who said it compromised his impartiality on the issue.

After a few seconds and some suppressed grins among courtroom observers, Burger noted that the other side of the case had also cited the speech in its written briefs to the court. "You should know that your opponent cited the same material," Burger commented.