Anyone who's paid a whit of attention to what goes on inside prisons -- not just prisons in war zones, but the ones where we happily ensconce our neighborhood crooks right here in the U.S. of A. -- knows there's always a potential for mistreatment of the "guests."

Those guests, of course, are none too pleased with the hospitality they've been accorded. They weren't model citizens in the first place. While it's by no means always the case, they can be stubborn, mean, violent. It takes a firm management hand to prevent escapes, fights, exploitation of the weak by the strong.

It's certainly no stretch to see how, in the pressurized world of a high-security slammer, those in authority would sometimes be tempted to use excessive and unacceptable force. To bang some heads. What stands in the way of such abuse?

Training, obviously. A correction officer has to be able to recognize what kinds of conduct amount to mistreatment and understand how to avoid them. Discipline. Those who guard prisoners have to know that abuses, if they occur, cannot be covered up, and that there will be unavoidable consequences.

Perhaps the key to humane treatment of prisoners, however, lies in the character of those assigned to oversee them.

No, you shouldn't need the sweet, patient temperament of a nursery school teacher to supervise a bunch of convicts. But you should have an instinctive appreciation of the fact that people in prison, no matter what the crimes that landed them there, are fellow human beings entitled to be treated with a basic level of decency.

You should be willing to grant them that decency, and dignity, not just because the rules say so, but because it's right.

Those who handle recruiting and hiring for correction officer positions surely try to make these judgments about candidates. Yet experience tells us that when people are put in situations where they're authorized to exercise strict control over others, character can be put to an acid test. Normal behavioral constraints can fall by the wayside.

The nightmare scenario is when a person who's authorized to use coercive force actually gets a kick out of making those under his (or her) control knuckle under. Would any properly run prison hire a sadist for a guard's job? No way -- but it shouldn't take anything away from all the conscientious and professional officers who work in our prisons to acknowledge that from time to time, their ranks are tarnished by a sadistic brute.

The dreadful disclosures out of Abu Ghraib and the shadowy network of U.S. detention camps and interrogation centers in Iraq and Afghanistan -- dreadful politically, dreadful as violations of standards of humaneness -- may well reflect that sort of rotten-apple dynamic.

It's known, for example, that Army Spec. Charles Graner Jr. -- the grinning, arms-crossed dude photographed along with Pfc. Lynndie England as they stood behind a tangled pile of Iraqi prisoners -- had been accused in a divorce case of beating his wife, among other forms of domestic violence.

"Charles picked me up and threw me against the wall," she said in a 1998 court document, according to The New York Times. Graner, an ex-Marine, worked as a correction officer at a southwestern Pennsylvania prison where an abuse scandal erupted. Because of privacy rules, the Times couldn't determine whether Graner himself had been disciplined for what was described as routine beating and humiliation of inmates.

So this prince of an individual gravitates into a reserve unit of MPs and winds up as a supervisor of sorts at Abu Ghraib. That was a disaster waiting to happen. Because if guards in a civilian prison sometimes are tempted to get rough with their charges, think about the atmosphere in a prison for people often regarded as "hostiles," and thus with a toxic mix of loathing and contempt.

Not only that, but the mission at the prison near Baghdad wasn't just to keep the inmates under control. It was also to pry loose information useful to the U.S. effort, possibly even saving lives. Soldiers such as Graner and England evidently got the idea that forcing Iraqi men into demeaning, sexually charged poses was a fine way to break them down and get them to talk. And with sadism often having a sexual component, they may even have gotten their own jollies in the process.

It's small consolation that American abuse of Iraqi prisoners is a flyspeck compared with the monumental crimes against his own people perpetrated by Saddam Hussein. We're supposed to know better, and to be better. At least, that's what we'd like the rest of the world to think.

Sadly, the failures here are manifold and profound. Failures of training and discipline. Failures of communication and command. Failures of character and judgment.

Fundamentally, those who have shamed our country must not have recognized that what they were doing was wrong. Maybe they just told themselves that since war is hell, anything goes. Of course, a good definition of something hellish is that it strips people of their common humanity.