His head bowed, eyes downcast, hands folded in his lap like a contrite child, Pfc. Robert R. Garwood sank into the hardwood chair as a psychiatrist testified that he believed the accused Marine turncoat was not "bright" enough to fabricate the richly detailed saga of his capture, torture and 14-year odyssey in Vietnam.

"It would take a novelist to make it up," said Dr. Emmanuel Tanay, 52, a Nazi concentration camp survivor who testified today as an expert witness for the defense. "He doesn't have the intellect or the talent to make it up." f

He spoke as if Garwood weren't there as he recounted what the private told him about his capture. It occurred in a beach gunbattle with the Vietcong. He was shot in the arm, dragged into the jungle praying he would die to avoid torture, beaten, tourtured and forced to eat rats or starve. w

He became the prison camp pet -- "kept in a cage like a pet monkey," said Tanay.

Finally, Tanay testified, Bobby Garwood snapped, a 19-year-old Marine just weeks away from rotating home. "He suffered an absolute psychic trauma in Vietnam, the kind of experience no human being, no matter how resistant or strong, could survive without suffering emotional injuries," said Tanay. Subhuman, primitive conditions as a jungle captive triggered his mental illness -- "traumatic stress disorder" -- which Tanay said made Garwood regress to "childlike, animal-like behavior" in which survival became the overwhelming drive.

"The only important thing was to get food," he said. Garwood's "conscience did not operate."

His regression to helplessness led him to identify with the agressor -- the enemy -- and he understandably wrapped himself in "adaptive" behavior, much as a chameleon takes on the enemy's uniform, carried their guns -- Garwood told Tanay he only "cleaned" them, never used them -- and touted the enemy's goals to other prisoners, carrying a bullhorn to urge American soldiers to throw down their arms and desert.

But it was impossible for Pfc. Garwood, now 34, to understand his alleged misconduct as a prisoner, said Tanay. He was under too much stress, too much deprivation, Tanay said. He neither had the capacity to understand right from wrong nor to appreciate the alleged criminality of his actions under the Uniform Code of Military Justice.

Even now, Garwood wonders, if what he did was so terrible, why no other prisoners told him he was wrong, said Tanay.

"Because they were afraid of him, they didn't trust him," snapped Maj. Werner Helmer, the crewcut Marine prosecutor, during cross-examination today.

In Vietnam, Bobby Garwood was emotionally "run over by a truck . . . [then] the truck backed up," said Tanay.

The psychiatric defense of Robert Russell Garwood, the only prisoner of war to be court-martialed for desertion and collaboration with the enemy since 555 American POWs came home in 1973, was officially launched. Tanay was merely the first psychiatrist to testify in a scheduled wave of psychiatrists to have probed the defendant on their couches. He was the lead-off defense witness in one of the longest and most complex trials in American military history.

The Detroit doctor, a forensic psychiatrist who has studied holocaust survivors and testifies regularly an an expert witness for fees of up to $1,500 a day, stripped Garwood emotionally naked before the five-man jury of Marine officers, all Vietnam veterans. He told the hushed court about Garwood's turbulent childhood, about a mother who abandoned him, about his lack of education and sophistication, that he sought out the Marine Corps as a "refuge . . . an asylum."

It was a background, he said, that predisposed the young Marine to the mental illness he developed in the jungles of Vietnam. There he was thrown in a hole and isolated. He latter watched the first American he had seen in months -- a Green Beret captain who befriended him and inspired him to resist -- die before his eyes.

Garwood, ever stoic in court, a mask of inscrutability, sank lower in his seat, biting the inside of his cheek. His eyes glistened with the hint of tears, but he did not cry. Soon there was a recess, and he fled to a private hallway to be alone.

He was not in control of his life or emotions then, nor in 1965, when like other prisoners of war, he became a Vietcong guinea pig, according to Tanay. "Mr Garwood describes himself as a piece of clay [who] could be molded," said Tanay, who interviewed the Marine in May in Detroit and again in November. From those interviews, recorded on five hours of videotape which prosecutors reviewed Thursday and the court impounded Garwood was "broken down," and virtually transformed into a "white Vietnamese," the phrase other American prisoners have used on the stand to describe Garwood.

"If a man can be reduced to eating rats and talking about them as a delicacy," said Tanay, "he can be manipulated" like Garwood.

He rationalized his behavior in his own mind, but didn't understand what was actually going on inside him, why he was so easily led around by the enemy, Tanay said. "The captor becomes like a parent . . . and the victim has to be grateful" for whatever he is given. "Even abused children respond to cruel parents. Garwood was reduced to the level of a beaten dog, but a dog still responds when you whistle."

Psychiatric opinion on what constitutes "brainwashing," a catch-all that includes various mental afflictions psychiatrists have used in describing Garwood, has been evolving since the Korean War, when the military was shocked at the number of American soldiers who were broken by the enemy and used for propaganda purposes.

Duress or insanity has been used as a defense in military and civilian trials with mixed success, according to Col. Robert E. Switzer, the military judge in the Garwood trial. "Toyko Rose" and "Axis Sally," women accused of treason in World War II for making propaganda broadcasts for the enemy, raised the duress defense but were convicted. F. Lee Bailey failed to free convicted newspaper heiress Patricia Hearst when he used coercive persuasion as a defense against her bank robbery charges. But a Vietnam veteran who killed his wife and used "post traumatic stress disorder" as a defense, saying he experienced an uncontrollable flashback from Vietnam combat, was recently acquitted.

The military's dilemma over how much a soldier should be required to resist under torture led to a revision of the code of conduct, the military's unofficial commandments, in 1977.

The five-man jury will be asked to apply a test for legal insanity to Garwood when both sides rest, probably in early February. It is a two-pronged test, says Vaughn Taylor, 33, one of Garwood's lawyers. First, the jury must ask, "Did Garwood have a mental disease at the time of the offense?" and "Did the disease cause him to commit the alleged crime?" If the answer to both is yes, two more questions must be raised: "Did the mental illness make Garwood not responsible for his conduct?" and "Did it [the illness] make him unable to conform his conduct to the law?"

"If the answer to either of those questions is 'yes' he's entitled to an acquittal," says Taylor, who once taught military law at Judge Advocate General's School in Charlottesville, Va.

A Navy medical board in Pensacola, Fla., earlier concluded that Garwood "did not have a mental disease at the time of the alleged criminal conduct" though it found he had an "avoidant personality from childhood, which was present at the time of the alleged criminal conduct." But the disorder, the board said, "in no way interfered with his ability to appreciate the criminality of his conduct or to conform his conduct to . . . the law."

Bobby Garwood has been "destroyed by the experiences he had in Vietnam," said Tanay. "He makes it pretty clear when you talk to him. Not only is he depressed, but he is suicidal, and remains so."

The last two years spent as an accused traitor under the media's microscope have aggravated the post-traumatic stress contracted in Vietnam, Tanay said. "He says, 'I'm tortured now; I have no friends, no relationships.'

"He felt he could survive and adapt in Vietnam because it was the enemy [torturing] him, but now it is his own country. He said, 'I don't own anything. I don't own my life. I have nothing.'"

Indeed, if convicted, Garwood will have nothing. He faces life imprisonment and the forfeiture of $140,000 in back pay, now held in escrow.

"What is the status of Garwood's soul?" the defense asked Tanay.

"I find it difficult to talk about [his soul] in his presence," said Tanay as Garwood stared at the floor.

The verdict could boil down to whether the all-Marine jury accepts Tanay's notion that every man -- even a Marine -- has a breaking point, a notion several jurors have said they don't believe. "Like you break a bone, you can break a mind," Tanay told them, if it is overwhelmed with too much traumatic experience, as Garwood's was.

Garwood's trial also raises one philosophical question -- where to draw the line between honor and survival -- a question the military partly resolved during Vietnam by dropping all charges against returning prisoners in Operation Homecoming who were accused of misconduct while POWs.

"It may be that honor isn't as important [as survival]," said Tanay. "The Bible says, "He who endures to the end shall be saved.' And if you don't harm anyone and manage to help others at times, you shouldn't be ashamed. To save one's own life is the ultimate form of resistance."