In Manhattan's Foley Square federal courthouse, where eight high Mafia executives are on trial, the judge summons the defendants' lawyers to settle a point of law. They make an impressive sight, so many legal virtuosos marching en masse to the bench, enveloping the judge in a wall of expensive pinstripes.

Suddenly, as he glances up, a flicker of alarm crosses the face of Judge Richard Owen. Standing right there at his elbow is one of the defendants, the notorious Carmine Persico, 53, known behind his back as "Snake." Persico is not breathing down Judge Owen's neck as the accused leader of the dread Colombo crime family. But despite the fact that Owen has given Persico permission to be his own attorney, the judge still looks uneasy as Persico solemnly weighs the proper boundaries of cross-examination.

"I think you're right," he says as Judge Owen defines the ground rules. Persico grins at the jurist, realizing that he has, if only for this brief moment, crossed that pin-striped line into respectability.

The mobster elected to become his own mouthpiece in August, prior to coming to trial on a 25-count barrage of federal charges, including labor racketeering and extortion. "By now I guess you all know that my name is Carmine Persico and I'm not a lawyer, I'm a defendant," he told the jury in his folksy opening address.

"Bear with me, please," he added, as he put on his gold-rimmed glasses and fumbled through his notes. "I'm a little nervous, too."

And so he became not a member of the cruel "commission" that regulates organized crime in New York City, as the government contends, but a middle-age man venturing into perilous legal waters to defend himself. He explained to Judge Owen that although he was only a high school graduate, he understood the case better than his own lawyer. Court observers believe that by depicting himself as the underdog, he hopes to win over the jury. "He's up against the professionals, and it makes him look sympathetic," says Harry Subin, professor of law at New York University.

Like the other defendants, his basic strategy is to concede the existence of the Mafia while insisting on their innocence. Persico told the jury not to be "blinded by labels," and at one point he said, "They are powerful," indicating the prosecutors, "not me." The Snake would have you feel that just because someone belongs to the Mafia, or La Cosa Nostra, that doesn't make him a bad person.

Soon after the testimony began, there came a moment of supreme drama. The government called its star witness, Fred DeChristopher, who turned the fugitive Persico over to the authorities in February 1985 and then, defying the code of silence, named him as the head of the Colombo crime family. The betrayal was heightened by the fact that DeChristopher, Persico's cousin by marriage, had allowed the gang boss to hide in his Long Island home when Persico's indictment on racketeering charges seemed imminent. Persico displayed a subtle wit and even professional restraint in questioning DeChristopher. His voice ringing with sarcasm, he asked: "You helped me when I came to your house?"

"I did," replied DeChristopher, 59, and that produced a knowing gale of laughter from the spectators.

"You couldn't buy socks," said Persico derisively, driving home his point that DeChristopher received a $50,000 reward for turning his cousin over to the FBI.

"You'd like to see me down the sewer," shot back DeChristopher. "Wouldn't you like to see me down the sewer altogether?"

With impeccable timing, Persico waited for the break in the courtroom laughter to reply: "I don't think the judge would permit me to answer that question."

"I know. I know what your answer would be."

Persico is credited with handling his own case adroitly. "From what I can tell, he seems to be defending himself with a good deal of skill," says Professor Subin, "but I gather he's had some experience with the law."

Persico, whose father, Carmine Sr., was said to be a soldier in the Genovese family, began his acquaintanceship with the criminal justice system while leading a Brooklyn street gang known as the Garfield Boys in the early '50s. In those days Persico was known as "Junior." When he was 16, he was questioned about the murder of a rival gang member. The following year he was ambushed and shot in both legs, probably by friends of the dead youth. A few months later he was accused of killing another youth in Brooklyn, but the charges against him were dropped.

Before his 20th birthday, "Junior" Persico became one of the youngest "made men" in the Mafia. Police intelligence agents claim that he committed a dozen murders in his rise to power. Although Persico has been arrested at least a score of times over the years, very few cases were ever made against him. Witnesses have tended to vanish, develop amnesia or just quit. But in the late '50s, Persico got himself tangled up in a relatively insignificant charge: hijacking. There were five trials before he was convicted in 1968 and sentenced to 14 years in prison. He served seven years and was then paroled. Despite his being behind bars, police intelligence experts believe that during this period Persico became the head of the Colombo family. "He was the gun for hire, and now he hires the guns," says a police source.

Meanwhile, as counselor Persico pores over the grand jury minutes and prepares his questions for cross-examination, the government builds its case. His co-defendants, other accused members of the Mafia's ruling commission, seem to regard the trial in various styles of studied indifference. They spend their days like great un-moving tortoises, sunning themselves in the admiration of their fans. On some days the courtroom holds just the ordinary trial buffs and sight-seeing attorneys dropping by to catch the action. But often enough our public celebrities come to see the celebrities of crime. James Caan, who played Sonny in The Godfather, attended the previous Persico trial (October '85 to June '86), in which he was convicted of racketeering. (Persico is presently held at the Metropolitan Correction Center and still awaits sentencing in that case.) Robert Duvall, who played the consigliere in the same movie, showed up a few times, apparently to study Persico's moves. And Persico makes his moves carefully. Although he is playing for very high stakes, he smiles at the jury and speaks to them colloquially, without lapsing into legalese. In the end this may be more effective than all the legal degrees in the courtroom.

"The law is so highly stylized that he may be doing a very clever thing," says NYU's Subin. "The jury may just want to hear someone tell his story."