NEW YORK--More than two years after Bernhard Goetz shot four young men on a subway, the question of whether he overreacted or read the situation clearly in thinking he was about to be mugged is being put to a jury.

Opening arguments were scheduled today in the case that ignited a national debate over the rights of citizens to defend themselves versus the risks of vigilantism.

The prosecution maintains Goetz panicked, and shot with an unlicensed .38-caliber handgun four youths who were only panhandling.

Goetz's lawyers counter that the threat was real and that Goetz, badly beaten in a previous mugging, realized he was in danger and did what he had to do.

Goetz, 39, is charged with attempted murder, reckless endangerment, assault and illegal possession of a dangerous weapon in the shooting of Troy Canty, Barry Allen, James Ramseur and Darrel Cabey on December 22, 1984.

Goetz said he shot the four, all 19 at the time, because he believed they were trying to rob him when they surrounded him and asked for $5.

Cabey has told a newspaper columnist the four were about to rob Goetz because he "looked like easy bait."

The jurors are expected to hear up to 40 prosecution witnesses and about 60 for the defense during the trial's expected four to six weeks.

"We will call the victims--thugs--[to testify]," said Mark Baker, one of Goetz's lawyers, Three of the victims have recovered completely, while Cabey is brain damaged and paralyzed from the waist down because a bullet hit his spine.

Cabey's attorney, civil-rights lawyer William Kunstler, said that Cabey probably will testify, but his mental competence is in doubt. "He doesn't even remember who Goetz is," Kunstler said.

Police said the four were carrying screwdrivers at the time of the shooting. All had arrest records, and all but Cabey have since been arrested. Two were imprisoned and one was sent to a drug rehabilitation center.

On Friday, state Supreme Court Justice Stephen Crane, the trial judge, refused a defense request to dismiss or at least delay the trial. Goetz's lawyers charged that the prosecution illegally withheld information favorable to the defense from the grand jury that indicted him.

The information involved descriptions from witnesses of the sequence of events.

The defense also said it needed time to find crucial witnesses whose names the prosecutor kept from them as long as possible.

Baker said the defense would seek to prove that Goetz fired five times in rapid succession. Police have said that Goetz told officers he shot all four youths then turned back to Cabey and shot him again, saying, "You don't look so bad, here's another."

The Goetz case meandered through the court system since his arrest.

In January 1985, a grand jury refused to indict him on attempted murder charges, accusing him only of illegal weapons possession. A second grand jury was empaneled, and in March 1985 it indicted Goetz on the current charges.

A judge later dropped the attempted murder charges, but the state's highest court reinstated them in July, holding that the prosecutor was correct to argue that Goetz's actions must be judged by whether he acted as a "reasonable man" might have in the same situation.