In the course of the morning, My Lai had gone from a peaceful farming village - where Americans had previously visited, handing out candy out to gleeful children - to an empty ghost town. The soldiers had scalped villagers, cut off hands, burned corpses, carved "C Company" into victims' chests. At least one village girl - a fourteen year old - had been raped and subsequently shot by an American soldier in front of her sister. The men gathered together groups of unarmed Vietnamese civilians and gunned them down. Only one American was injured: a GI who accidentally shot himself in the foot.

How had this event come to happen? The operation had been described as a search and destroy mission. The soldiers had expected a battle with the enemy which had so successfully evaded them previously through guerrilla tactics. Their company had suffered injuries from booby traps and snipers, taking damage from an enemy they could not find to fire back at. Confusion and chaos reigned in the Vietnam War, with the Viet Cong blending in with the villagers and making it hard to know who was who. The men of Charlie Company had certainly been frustrated by this situation in which they were being picked off from an invisible menace, so My Lai was their chance to take out what they thought was a Viet Cong base of operations.

When they arrived, however, they were not fired upon. In fact, the only people in sight were women and children. Yet in the minds of Charlie Company, any of these villagers could be Viet Cong (young boys had been known to fire on American soldiers). The order was given to fire on a retreating woman who was holding something, and Vernardo Simpson - thinking she might be carrying a weapon - shot the woman. She died, and the baby it turned out she had been carrying died as well. As Simpson describes it in this interview excerpt from the PBS Frontline special "Remember My Lai", something just snapped:

I just went, my mind just went, I didn't and I wasn't the only one that did it, a lot of other people did it. I just killed, once I started the training, the whole programming part of killing, it just came out... I just lost all sense of direction, of purpose. I just started killing in any kind of way I could kill. It just came, I didn't know I had it in me, but like I say after I killed the child my whole mind just went, it just went.

On March 15, Lt. Colonol Frank Barker had drawn up plans for an attack on My Lai, which intelligence believed was the headquarters for a Viet Cong battalion, and passed on the orders to Charlie Company's commander, Captain Ernest Medina. Following investigation of the incident, Lt. William Calley - the man who led the offensive and the only one to be convicted in the wake of the massacre - testified that he was ordered by Medina to kill everyone in the village of My Lai. Barker and Medina denied responsibility for My Lai, but there was little doubt among the men what they were supposed to do. Army Chaplain Carl Creswell describes the briefing in preparation for the operation:

I was division artillery chaplain, which meant essentially I went to every fire base in my division area, and the day before My Lai I'd gone down to Landing Zone...They were going to do insertion or combat assault or whatever it took in Pinkville which was, quite frankly, it was the home of the 48th VC Battalion.

And I went in there, I was just, it was just a courtesy call. I had no business there, chaplains do this, just stopped in to say "hello" and meet the new commander. And while they were there they had the maps laid out on the board and there was a major in there who was on the Task Force staff. And I remember he said, "We're going in there and if we get one round out of there, we're going to level it." And I looked at him and I said, "You know, I didn't really think we made war that way." And he looked at me and he said, "It's a tough war, Chaplain."

Kenneth Hodges: The understanding of the order that was given to kill everyone in the village. Someone asked if that meant the women and children and the order was "everyone in the village" because those people that were in the village -- the women, the kids, the old men -- were VC -- and they were Viet Cong themselves or they were sympathetic to the Viet Cong. They were not sympathetic to the South Vietnamese Army and they weren't sympathetic to the Americans. They weren't giving us any assistance. They weren't helping us in the war effort whatsoever.

Interviewer: So it was quite clear that no one was to be spared?

Kenneth Hodges: It was quite clear that no one was to be spared in that village.

Part of it surely was their initial training. An effective soldier must be trained to kill effectively, to not risk the lives of his unit, and that means following orders even if they do not seem ethical. If every soldier were to become judge over any order that came down to him, the chain of command would effectively disappear and every individual soldier would make their own decisions, with little cohesion or top-down planning. As part of their training, the men of Charlie Company certainly had to have this lesson programmed into them; following orders had to become second nature. This sort of training surely prepares a mind to do things that in normal circumstances would cause a human being to stop and reflect.

Yet more than that, the orders from the top (to be merciless in their assault on My Lai) and the breakdown in the distinction between enemy soldiers and civilians must have mentally set the stage for what was to come. It laid down the mindset these soldiers were operating under; it gave them a structure that helped them all slip into atrocity-mode after one initial act sparked things off. In normal circumstances, the soldiers would have stopped after realizing that they were not in danger, that they were slaughtering unarmed innocents; but because of the priming by their commanding officers, their minds were not able to make that proper click, and instead they just started doing what everyone else around them was doing. They snapped and went berserk.

I think the lesson here is just how powerful structural processes like the army chain of command can be. In the years following World War II, many people in the Allied countries sought to explain the country-wide crimes of Nazi Germany by trying to find something innate in the German people that would make them able to fall in line under a leader like Hitler, to commit the atrocities they did. Americans wanted to believe they were different, that they themselves were incapable of such deeds.

We now know that there is no simple biological explanation - a German tendency toward going along with fascist rule or following vile orders - and My Lai proves that even good old American boys have the potential within them to do the worst of deeds. And that means, in some sense, that such a potential lies in everyone, in every human being. People are generally not born murderers, not born to gas Jews or massacre villagers. Instead, to some significant extent, it is the situations they are put into and the programming they are exposed to and the structures they are trapped within which can turn normal people into monsters. As Michael Albert once put it: