Ken Kerney said he joined the Army to fight communism, but he would face another struggle in Vietnam.
Entering a special fighting unit in one of the country's most dangerous war zones, he watched in 1967 as his new peers sliced ears from enemy dead and opened fire on unarmed villagers. He had a choice to make.
“It's a line, and you have to ask yourself, `Do I want to cross it?'” the former Tiger Force rifleman said recently. “Because once you cross that line, you'll do it again and again. It will escalate. And that's exactly what happened.”
He said he never crossed the line, but others made a different choice.
More than three decades after the war crimes of Tiger Force, former platoon members still debate what caused the unit to commit atrocities.
But scholars say the platoon's actions mirror long-held theories of abnormal behavior.
To sociologists and military experts, the problems of Tiger Force began with its battalion leaders.
The Geneva Conventions and the Army's own rules have long forbidden targeting noncombatants, but several commanders gave opposing views to Army investigators on whether soldiers had a right to shoot unarmed people.
Some said they could under certain circumstances and some said they couldn't at all.
Those conflicting directives filtered down to soldiers, who often cited them to investigators and The Blade as a reason they killed unarmed people.
Combined with the pressure to produce enemy “body count,” the unclear directives could have given some soldiers their own perceived authorization to kill prisoners and unarmed villagers.
“They don't see themselves as responsible agents,” said Dr. Herbert Kelman, a Harvard University sociologist. “They tend to see themselves more as tools, as acting on behalf of the authority.”
Armed with conflicting directives, the special platoon commonly went into combat on its own - breaking into small teams for long missions in distant areas of operation.
To former Sgt. William Doyle, the lack of oversight allowed Tiger Force soldiers to become arsonists, rapists - and killers.
No one was watching.
“There are just four or five of you together. If you trust the guys you're with, if you have good men with you, you don't have to worry about what you do. You can do any damn thing you want to, anywhere you want to,” Mr. Doyle recently told The Blade.
“Who's going to check you? What's the checks and balances? There's not any,” he said. “You're calling all the shots.”
As the war intensified, so did the platoon's atrocities - from body mutilations and prisoner executions to the killing of civilians.
The escalation mirrors findings of sociologists who have studied war crimes. Each incident desensitizes soldiers enough to permit an even more vicious act, said military sociologist Morten Ender of the U.S. Military Academy at West Point.
“It becomes ingrained,” Dr. Ender said.
The atrocities also increase in severity as the soldiers experience the psychological frustrations of combat.
In a war where fellow soldiers often died from snipers or booby traps, the mix of fear, anger, and mourning in the survivors can quickly dehumanize the enemy.
In their zeal for perceived vengeance, war criminals often stretch the definition of “enemy,” said Dr. Robert Lifton, a psychiatry professor at Harvard medical school who has studied Vietnam veterans.
That was particularly the case in a place where people looked different, spoke different, and acted different - where stereotypes could feed the anger of young Americans overseas for the first time, sociologists said.
“Civilians very easily replace military targets - not just happenstance, but become psychologically perceived as something close to the enemy,” Dr. Lifton said. “So desperate were they psychologically for an enemy that any Vietnamese could fill that role.”
Former soldiers have pointed to the case of Sam Ybarra. By September, 1967, the point man was already known for cutting off ears and scalping prisoners, but he became even more vicious after his best friend, Kenneth “Boots” Green, was killed by a North Vietnamese sniper that month.
“After Boots died, he [Private Ybarra] got creepy,” former Private Kerney said in a recent interview. “He had his mind made up that he was going to kill as many people as possible and nobody was going to stop him. Nobody.''
Private Kerney was among the many unit soldiers who did not commit war crimes, according to Army accounts and soldiers' recollections.
Psychologists and sociologists say they're not sure what causes some soldiers, but not others, to commit atrocities, except that each soldier carries a unique moral code and tolerance for outside pressures.
Some of those who didn't commit atrocities said they tried to stop the crimes when they could. Spec. Dan Clint said one night, while he was the lone soldier on guard duty, he pondered executing a sleeping Private Ybarra.
“I was going with the idea that if I got rid of Ybarra I'd be saving a lot of innocent lives,” he said recently.
But he decided against it and chose not to complain to commanders about the private, either. In fact, only two platoon soldiers were known to have complained about the killing of civilians, according to Army records.
The rest kept quiet - citing fears of retribution and a need to depend on fellow troops who, despite their war crimes, helped protect the rest of the platoon in combat.
The code of silence was embraced by new soldiers who entered the unit after the killing of prisoners and civilians had begun.
That's to be expected because most replacement soldiers would have had to assimilate to survive, said retired Col. Ramon “Tony” Nadal, who taught leadership and psychology at West Point.
“It takes a major set of gonads to go into a combat arms unit in the middle of a war and be the first guy - the new guy there - to say to all you old grizzled veterans who are armed and may have been committing war crimes, `I'm not going to do that,'” he said.
But, Colonel Nadal, a former special forces and company commander in Vietnam, said he had no tolerance for soldiers who crossed the line.
“None of that is an excuse,” he said. “Most of the units in Vietnam did not do what this unit did.”
Blade staff writer Mitch Weiss contributed to this report.