Don't get me wrong. The killing of 16 Afghan men, women and children by an American soldier without provocation and without threat to his own life (or so it appears) was wrong. Completely wrong. It is an unspeakable tragedy for all those involved. It places the lives of other Americans in danger.

I'm no fan of the myriad "abuse excuses" that once held sway in the American legal system. Those who know the difference between right and wrong and have the capacity to choose are responsible for choosing wrongly. End of story.

Sort of.

All of the questions about why it would happen and how it could happen and the attempts to portray this particular soldier as some sort of aberration also miss some important points.

From what I can tell, this man did not join the military as an evil man who somehow escaped the screening that should have eliminated him from the start. He was on his fourth tour of duty in hell. His wife and family were thousands of miles away. He saw unspeakable things. He faced horrendous threats to himself and his fellow soldiers.

And he cracked.

The military tells us that soldiers are screened before they are sent to combat. Right. Sure. Soldiers can barely get help when they come home from combat as certifiable messes. How much screening do they get beforehand? How much money can the military afford for screening when just a few years ago it was fighting for body armor, when military hospitals were an embarrassment and a horror? If the screenings were really so thorough, would anyone qualify for a fourth tour?

Understand, I am not making excuses. These are observations -- and I hope important ones. They are not intended to exculpate, but to help us understand, to help us appreciate, to help us avert the tragedies we don't even know about.

It happened in Vietnam. John Kerry was excoriated during the 2004 election for saying that decades before. But if you look at his speeches carefully, or sympathetically, if you strip them of any vestiges of politics or arrogance, there was truth to what he said about the emotional toll a certain kind of war takes on the soldiers who fight it: the horrors of never knowing for sure who your enemy is, the ease of confusing innocent civilians with attackers who hate you and would, maybe, kill you.

We can all pound our chests and look for ways that this particular man is different from the rest of us: He had a record for fraud, maybe; he had a temper, maybe; he wasn't really fit for the fourth tour, maybe.

Scratch the surface of lots of people who serve bravely and honorably in the U.S. military, and you'll find many who would not be awarded an Eagle Scout badge. Exclude them all, and you wouldn't have a military. Pound your chest too hard, and you'll be pounding away not at one soldier, but at many of them.

The lesson of this is not that a soldier who goes wrong should avoid responsibility.

The lesson is for the rest of us, who expect more than we should, who help less than we can, who pretend that the explicable is indeed inexplicable so that we feel no obligation even to try to understand, much less to prevent.

My heart goes out to the families of those who were brutally murdered, and to the soldiers who will face even more danger on account of the backlash.

But it also goes out to the family of the man charged, to his wife and children left behind, pariahs, singled out, dismissed as different from the rest of us, when really, for so many, there but for the grace of God