I can't get those debased Marines off my mind -- the ones who turned up in a video a few weeks ago urinating on the bodies of dead Taliban fighters in Afghanistan .
Secretary of State Hillary Clinton at least got it half right when she said she felt "total dismay" after hearing the story: "It is absolutely inconsistent with American values, with the standards of behavior that we expect from our military personnel and the vast, vast military personnel, particularly our Marines, hold themselves to."
What's the half she left out? The same half people expressing disgust at sin and debauchery almost always leave out -- the half that acknowledges with humility that even those of us decrying this horrific act of dishonor are ourselves capable of evil.
This half-truth is why I bristled at George W. Bush's Manichaean language that dismissed our enemies as "evildoers." Well, yes, some of them indeed committed evil acts, but such labels fail to acknowledge that we ourselves are never free from evil impulses.
Even those of us who are Presbyterian  -- and, thus, acknowledge John Calvin as our major theological parent  -- are willing to concede that Calvin didn't get it all right. Indeed, Calvin's name today often is whispered instead of shouted among Presbyterians, and he's seen by some as something of an embarrassment, even though many of the knuckle-headed ideas attributed to him really were products of some of his disciples, who became zealous hyper-Calvinists.
Nonetheless, Calvin understood that humans carry with them a large and ready capacity for depravity. Indeed, our Reformed Tradition doctrine called "The Total Depravity of Humankind" grows out of this thinking. The doctrine is not quite as bad as it sounds, but it acknowledges that humans -- in whom the image of God still exists, though it's stained by sin -- are stuck in sin and its consequences and cannot rescue themselves. Thus, they need a savior.
Well, we can argue -- as people like Bishop John Shelby Spong and Matthew Fox do with vigor -- that this kind of theology is destructive and not inviting to outsiders. But I see no way to get around the sad reality that, however we explain it, all of humanity is capable of sin, even those designated as saints.
I'm not saying all of this to excuse those Marines. What they did was loathsome. They dishonored children of God. They spat (or worse) at life itself. They cheered for death. Their actions showed that they considered certain people to be subhuman. Nothing about their actions was laudable or excusable.
But once we say that -- and we must say that, especially as Americans as we struggle to find words of apology to the families victimized by this maliciousness -- we also must say that our standing in the court of moral rectitude is always compromised by what old John Calvin, in his Institutes of the Christian Religion , called "our miserable destitution and ignominy" resulting in what the Handbook for Today's Catholic calls "division, pain, bloodshed, loneliness and death."
So what are we as Americans represented by those Marines supposed to do now? First, of course, insist on a thorough investigation to find out why the perpetrators thought they could get away with such an execrable act. And if that investigation reveals a rotten subculture within the Marines, we must insist that it be exterminated.
Then we must find ways to express our remorse that our representatives did this, and we must condemn such acts in the way Hillary Clinton did. But we cannot stop where she stopped.
We also must say we recognize that even those of us decrying the act carry the capacity for evil within us -- even as we pledge to do our best to resist it. We are imperfect people and we are sorry.
But we are not shocked because we know that all of humanity is thoroughly infected with evil.
[Bill Tammeus, a Presbyterian elder and former award-winning Faith columnist for The Kansas City Star, writes the daily "Faith Matters" blog  for The Star's website and a monthly column for The Presbyterian Outlook. His latest book, co-authored with Rabbi Jacques Cukierkorn, is They Were Just People: Stories of Rescue in Poland During the Holocaust . Email him at firstname.lastname@example.org.]