They had just crossed Dorsey Creek bridge on the Naval Academy grounds, two midshipmen on their way home after a night on the town, when their Porsche veered off the road and hit a tree.

Scott Thomas was thrown from the car to his death. His roommate, Midshipman First Class Michael R. Olmstead, survived, but another ordeal lay ahead.

In a makeshift courtroom in the academy's Rickover Hall, Olmstead now watches somberly as a prosecutor tries to convince a jury of six officers that the midshipman before them is guilty of involuntary manslaughter, of recklessly causing Thomas' death.

Outside the Naval Academy's walls, the incident might be dismissed as simply a case of exuberant drinking, youthful driving and senseless death. But inside these cloistered grounds with their monuments to bravery, it is an occasion for the military's most visible and personal ritual of humiliation -- a court-martial, the first at Annapolis since 1922.

For two days Olmstead has faced his jury of six stone-faced officers in a room draped with green felt and the spectacle has aroused a conflicting array of emotions on this manicured campus.

From some midshipmen comes a possessive protectiveness of both Olmstead and the academy, whose reputation has suffered in recent months from a sex scandal, complete with a blue movie, that led to the widely publicized expulsion of three midshipmen.

"This is the Navy," said one upperclassman, declining to discuss the Olmstead affair. "We live together here. We have these loyalties. It's like a family. We don't talk about these things."

But the decision by the academy's superintendent, Vice Adm. William Lawrence, to court-martial Olmstead has assured that it will be talked about, whether in the corridors of Bancroft Hall, which they say is the world's largest dormitory, the streets of Annapolis or wherever academy graduates gather.

Some midshipmen are puzzled by the decision, some shocked. A few feel sorry for Olmstead, a somewhat stocky, freshfaced 21-year-old from Haddon Heights, N.J. Others contend he deserves whatever he gets.

"You know," said one, "a human life was involved."

And a few midshipmen harbor the suspicion that Olmstead is being court-martialed as a warning to all who would violate the academy's strict code of conduct and character.

"We think the superintendent is trying to set an example, a precedent . . . to make it clear what will happen with drunkenness incidents," said one midshipman in Olmstead's own tightly knit company, the 30th. "Some might say it's out of character for him [the superintendent] to be so tough, but I think he's doing his job, and well. It's an educational experience for the whole Navy."

The superintendent himself, who stands in a position of extraordinary power over his 4,400 students, asserted this week that his decision to court-martial Olmstead was based solely on the facts of the case, which he declined to discuss.

But Lawrence also made it clear he believes the academy student is special, a position his conduct should reflect. "I point out to the midshipmen, 'You are put up on a pedestal here. The country wants to look up to military officers as persons they can be proud of.'"

Indeed, six years as a prisoner of war in Vietnam convinced Lawrence that the academy is producing just such men. In his prison in Hanoi, Lawrence recalled, "Naval Academy graduates as a group stood out, the ones who stood up and took charge when the going was toughest."

Nearly six decades have passed since a superintendent has seen fit to convene a court-martial. During those years the academy relied on its in-house, noncriminal administrative conduct system" to handle breaches of discipline ranging from nonregulated haircuts to assault and theft. This system's maximum penalty is expulsion (often as an enlisted man).

That last court-martial now seems worthy material for a Gilbert and Sullivan operetta. It concerned a member of the Class of 1923, charged with hazing a plebe (academy slang for freshman).

According to transcripts, the plebe charged that senior Francis W. Lauret had called him to his dorm room and ordered him to perform 20 "stoop falls" (a type of calisthenic), apparently as punishment for bad table manners and failing to correctly answer a question concerning a fine point of seamanship: "What is a doghouse?"

While this resulted in no physical harm, it was "humiliating and oppressive," the plebe testified.

Following demonstrations of how the plebe allegedly mishandled his silverware and testimony that he learned over the table when eating soup, the court convicted Laurent. However, the records show his conviction was later overturned and he graduated with the Class of 1923.

Now, 58 years later, another midshipman's future hangs in the balance before a jury of two Marine and four Navy officers. If he is found guilty, Olmstead faces maximum penalty of expulsion from the academy, forfeiture of all pay and benefits and three years in prison.

One friend feels that the defendant has already "suffered extremely" through the loss of Thomas, his close friend and roommate. The two met as plebes, when they were both assigned to 30th company. They stood side by side in their photograph in the academy's yearbook, Lucky Bag, and roomed together on the second floor of Bancroft Hall.

Often, they took liberty together, driving down to Virginia to visit friends or spending a night on the town in Annapolis, a friend recalled.

Olmstead wanted to attend the Naval Academy almost since kindergarten, according to his mother, Catherine, who has sat behind him in the courtroom, her hand often entwined in her husband's as the testimony has unfolded. She had wanted him to be a doctor, she said, and gave him "doctor toys" as a child, "but he wanted to play with ships and guns and little soldiers."

Now, in his dress blues, Olmstead sits in Room 301 of Rickover Hall after a chain of events that began on a May evening last year. On that night, he and Thomas and three other off-duty midshipmen walked into the Library, a dinner and dance club in Annapolis. They talked and dance and drank, running up a tab of $68 before the evening was over, according to testimony in the case.

Shortly after 2 a.m., Olmstead's white Porsche 914 crossed the narrow two-lane bridge over Dorsey Creek, just inside the academy grounds. Failing to follow the road's curve to the left, the car slammed into a tree and turned over.

Thomas was thrown from the car and killed. Olmstead, pinned underneath, suffered minor injuries. A test taken that night showed he had a blood alcohol content of 0.199 per cent. (In Maryland, levels of 0.100 percent or more are considered to indicate intoxication.)

On that much both the defense and the prosecution agree. But the key issue in the case will be who was driving the car when it crashed.

Lt. Cmdr. John Holt, Olmstead's attorney, contends that no one -- not even his client, who was lapsing in and out of an alcohol-induced blackout, can say with certainty who was in the driver's seat. The prosecutor, Lt. David Acton, maintains that he will prove the driver was Olmstead.

In testimony this week, Midshipman Anthony Gurnee, one of Olmstead's and Thomas' company mates who was with them at the bar that night, said he left the Library to find Olmstead having trouble unlocking the door of his Porsche. "I told him he wasn't in any condition to drive," Gurnee said from the witness stand.

Gurnee and two other midshipmen have testified that Olmstead was persuaded to give up his keys and that Thomas got into the driver's seat. But as the other three midshipmen left the parking lot in their own car, Gurnee testified, he got a view of the Porsche and saw Thomas' arm resting on the window sill on the passenger side. Under cross-examination by Holt, however, Gurnee said he was not "100 percent certain" of what he saw.

As the court-martial continues, Holt is pinning his defense on that uncertainty and on a second question he has raised about whether whoever was driving was doing so recklessly. Holt maintains that the smashup was purely and simply "an accident," and that the spot where it occurred is an "inherently dangerous" intersection.

Since the court-martial began, no mention has been made of another incident -- one that has raised doubts in some midshipmen's minds about the handling of the charges against Olmstead. That seemingly similar 1978 case was handled through the internal administrative system and not through court-martial.

Both cases involved drinking and singlecar accidents on the academy grounds. In both, one midshipman survived to face allegations that he had caused the death of the other, a close friend.

According to accounts of the 1978 incident, the two midshipmen were chasing a civilian car when their Corvette sailed over a sea wall at close to 60 miles an hour and sank, killing one of the occupants.

The academy initially charged the survivor, Midshipman Joel Dykes, with involuntary manslaughter, then without explanation, reduced the charge to reckless driving and conduct unbecoming an officer. The case was handled under the administrative conduct system. Dykes resigned from the academy rather than face expulsion and is now fighting attempts to induct him as an enlisted man.

The court-martial is likely to continue for another two weeks before a verdict is reached. Olmstead is still attending classes and there has been no official announcement that a court-martial is even taking place. The starched and polished midshipmen stride from class to class on the floors below Room 301, leaving Olmstead to his fate.