It came without warning, a sudden, jarring BANG! of the gavel that riveted every eye in tiny Courtroom No. 1 at Quantico Marine Corps base on the judge, Lt. Col. Eligah D. Clark.

In his deliberate, understated way, Clark admonished Cpl. Lindsey Scott's chief defense attorney for making a caustic remark to the woman who had just testified that Scott raped and tried to kill her at Quantico in 1983.

He would not permit cross-examinations to descend into argument, Clark said, adding, "Everyone's aware of the significance of this trial, not only for Corporal Scott, but for the perception of military justice in general."

Clark's remark affirmed what has become obvious: that there are two defendants on trial in the sensational whodunit under way at Quantico. One is Scott, a 32-year-old husband and father who served nearly four years of a 30-year prison sentence before his conviction was overturned last summer. The other is military justice in the United States Marine Corps, which conducted Scott's first, flawed court-martial in 1983.

Media scrutiny at the current proceeding, which began Monday, is intense. In addition to the gaggle of reporters and illustrators in the back of the courtroom, a CBS producer from Los Angeles sits through every minute of the trial, taking copious notes and sketching key scenes in the courtroom drama. He has already paid thousands of dollars to Scott and three other figures in the case for exclusive rights to tell their story in a made-for-television "docudrama."

In a room down the hall from the court, a handful of civil rights activists and representatives of victims' rights groups watch the proceedings on closed-circuit television. Both groups say they are there to ensure a fair trial. Scott is black; the victim is white.

The Marines, perhaps partly in response to the scrutiny, seem determined to conduct a model court-martial, above even a suspicion of taint. Judge Clark, who is black, has repeatedly instructed the seven jurors (all marines and, in compliance with Scott's wishes, all officers) about the requirements of the Uniform Code of Military Justice, which governs procedures in such trials.

The jurors, most of whom said in pretrial screening that they had seen a CBS "60 Minutes" piece on Scott or had read about the case, have complied with the judge's instructions scrupulously. One took it upon himself on the third day of the trial to tell the court that the victim reminded him of a woman he knew slightly years ago; another reported that she had overheard a remark in the restroom concerning the case.

Each time, the judge asked if the juror's impartiality had been affected; each responded solemnly that it had not.

Under military rules, Scott could be convicted on a vote of five of the seven jurors. One member of the panel is black.

In the 1983 court-martial, Scott's civilian attorney, Ervan E. Kuhnke Jr., made what a military appeals court later said were astonishing mistakes in his attempt to establish an alibi defense for Scott.

It was on the grounds that Kuhnke -- whose name Scott had found in the Yellow Pages -- had presented an incompetent defense that the nation's highest military court set aside Scott's conviction last July.

While the transgressions at the first court-martial were Kuhnke's and not the Marine Corps', they nonetheless helped foster a public impression, particularly among civil rights groups, that Scott was railroaded by the Marine Corps. Scott has consistently denied that he committed the crime.

The groups have alleged -- and Scott's new attorneys have suggested in court -- that military investigators singled out Scott as a suspect prematurely, perhaps because they were under pressure to resolve a highly visible and violent crime.

This time, with the significant exception of a witness who is expected to depart from her original testimony and say she saw Scott miles from Quantico at the time the attack took place, the evidence has not changed. But the differences from the first court-martial are nonetheless great.

Scott has an aggressive new pair of attorneys. One, John F. Leino, is a member of a prominent defense firm, Howard & Howard of Alexandria. The other, Gary R. Myers, is a veteran defense attorney who once represented a defendant in the My Lai massacre trials in the Vietnam era.

Four years ago, according to testimony during the appeal, Kuhnke did not conduct thorough interviews with witnesses before he questioned them on the stand; one result was that his cross-examination of government witnesses tended to elicit testimony that seemed damaging to his client.

In grilling an agent of the Naval Investigative Service who worked on Scott's case, for example, Kuhnke asked how the victim came to identify Scott's car as the one in which she was raped and forced to commit sodomy. The agent responded with a lengthy -- and apparently damaging -- account of the woman picking the car out of a parking lot, recognizing a number of details that she recalled from the night of the attack, and then trembling and becoming upset.

Leino and Myers, aided by a military lawyer assigned to the defense team, have prepared for Scott's second court-martial for months, interviewing all the witnesses.

In cross-examinations of prosecution witnesses in the trial's first week they seemed to pound home crucial points for the defense that were muddied or overlooked in the first trial.

For example, when the investigator who handled the case in 1983 testified last week that the victim pointed out two men in addition to Scott from photos and a lineup, Leino asked him, "Is that your standard for a positive ID in a rape case?"

"No, sir," responded the investigator.

Leino and Myers also have made a point of attacking other government testimony that went virtually unchallenged in 1983. In response to investigators who have testified that they saw smear marks on the passenger side of Scott's car, indicating it had been wiped down, apparently to erase forensic evidence, Scott's attorneys have asked why photographs of the car do not reveal the marks.

In his opening statement at the 1983 trial, Kuhnke promised that he would establish an alibi proving that Scott could not have committed the crime.

When the alibi failed to emerge from testimony, Kuhnke seemed to compound the damage in his closing argument, when he said: "I admit that the defense did not prove an ironclad alibi case . . . . But that's not my burden. The government has to prove that this man did it beyond a reasonable doubt. I don't have to prove to you that he had . . . his alibi."

At another point in his summary, Kuhnke seemed to lose track of his thoughts for a moment, and then said, "I'm not as well organized as . . . . " He did not finish the sentence.

The current court-martial is expected to last another week to 10 days, two or three times the length of Scott's first trial. Both sides are planning to call more witnesses than in 1983 and, judging by the proceedings so far, both direct questioning and cross-examination will be more thorough.

At this point in the trial, a number of critical questions remain unanswered, among them:

Did the jurors believe the 27-year-old woman, now a Rochester, N.Y., resident, who pointed her finger at Scott on Wednesday, identifying him as her assailant?

Or will the jurors believe a former Zayre store detective who is expected to depart from her testimony in the first trial and say this week that Scott was miles away from the marine base at the time of the assault?

Will Scott testify in his own defense, as he did in the 1983 proceeding?