Maybe the beheading of Nicholas Berg will shut them up.

Meaning the people who keep asking why Americans should care about the mistreatment of Iraqi prisoners. I’ve received e-mails from a dozen of them, read their letters in newspapers.

Perhaps you’ve run into them too. Sure, they say, what our soldiers did was terrible, but the Iraqis have done much worse. They didn’t cry over those corpses in Fallujah. Why should we lose sleep over a few roughed up prisoners?

It’s a minority view, but a persistent one. As one individual put it in an e-mail summing up his opinion: “So what?”

The answer is so obvious as to be embarrassing: Since when are we content to be judged by the moral standards of those whose behavior might be called animalistic, were that not an insult to animals?

After all, we’re talking about people — and I use the term lightly — purported members of al-Qaida who decapitated Berg “on video” and posted it to the Internet. The murder of the 26-year-old businessman from West Chester, Pa., was revenge, they said, for the abuse of the detainees.

So by the reasoning of that persistent minority, are we now free to chop the heads off Iraqis in our custody? Could we justify it by saying the enemy has done the same?

The sad part is, some of us would say yes.

The events of the last three years have revealed something poisonous and mean in the American character. As much as we claim our struggle against terrorism is not a clash of cultures, not a war of Christendom versus Islam, there are too many times over these last months when it has seemed exactly that. And worse, when some of us have seemed eager for it, chillingly dismissive of the need to raise questions or speak cautions.

Think Rush Limbaugh claiming American soldiers were only letting off steam. Think Dick Cheney telling critics of Defense Secretary Donald Rumsfeld to “get off his case.”

Was it just three years ago that we were a nation of unquestioned moral authority where terrorism is concerned? Seems like a lifetime.

I say this as someone who considered George W. Bush’s address to a joint session of Congress nine days after the 9-11 terrorist attacks one of the great presidential orations of all time. In fact, it made me glad he was president. The moment, I felt, did not call for Bill Clinton’s bottom lip biting and moist-eyed earnestness. Rather, it called for just what Bush gave it: moral starkness, iron resolve and a with-us-or-against-us line in the sand.

But I didn’t see then what I see now. Namely, that leadership requires more than certitude. Indeed, that certitude without openness and intellectual rigor is pretty much just arrogance with a fancy name. It is no surprise, then, that this scandal happens on the watch of the most secretive and ideologically inflexible administration in recent memory. What we see in the pictures from Abu Ghraib prison smacks of license, the freedom to do as one wants under cover of secrecy because one is righteous beyond all doubt or need for accountability.

Where could soldiers and intelligence personnel have gotten that sense of license? It flows from the top down.

And anyone who considers this a matter of serving to the goose the sauce that has already been served to the gander is simply wrong. Not just because the scandal rips the nation’s few remaining tatters of moral authority, recruits new killers to the army of terror and endangers people like Nicholas Berg.

But also because it’s a fallacy to think we can fight terrorism with its own weapons. We don’t fly airplanes into skyscrapers. We don’t take hostages and behead them. And we don’t — or at least we didn’t — abuse prisoners. That’s not who we are. And we won’t prevail in this struggle by becoming what we abhor. Or by losing faith in our own core values.

If we can’t win this fight on our terms, we can’t win it at all.

– Leonard Pitts Jr., winner of the 2004 Pulitzer Prize for commentary, is a columnist for the Miami Herald.