In the summer of 1990, I drove through Chile with a list of names, looking for survivors of a certain kind. They were mostly middle-aged or elderly men, retired mayors and labor leaders and peasant activists. All had been imprisoned by the secret police in the military-ruled 1970s, and all had been tortured.

Even after many years, they were embarrassed and pained to talk about their ordeals, especially the more disgusting aspects. One man had been forced to eat his own excrement. Another had been subjected to simulated rape by German shepherds. A third had been locked inside a sweltering metal container with two other prisoners on the grounds of an abandoned villa with a swimming pool.

"We were cramped together, never allowed to wash. The heat and the stench were terrible," he told me, his hands trembling. "In the dark, we could hear screams all day and sobbing all night . . . The guards would splash in the pool and pass by the cells, saying they were going to kill this one and castrate that one. I don't know if you call that torture, but it was horrible."

Hearing those stories, I felt sickened and shocked, often unable to eat until the next day. I could not reconcile the dignified, literate culture I had come to know with the sordid, vengeful acts people described. It seemed as if Chile's values had been turned upside down by dictatorship, with thugs imprisoning intellectuals and respectable people pretending nothing was wrong.

Eventually, democracy returned to Chile, and I moved on to other conflicts, other stories. But now, more than a decade later, I have found myself confronting the question of torture again. This time, it is not in the dungeons of a South American dictatorship -- so easy to dismiss as beyond the pale -- but in the detention facilities of American military forces. And this time, I have begun to worry about what it is doing to my own society, as we hear reports of abuses and look the other way.

In my work as a foreign correspondent, I have interviewed men released from U.S. detention in Afghanistan who described a variety of abuses, some of which appeared aimed less at intelligence gathering than at humiliation and debasement. One dignified police officer, who had worked briefly for the police during Taliban rule, told me his U.S. captors had photographed him naked, mocked him while he used the toilet and twisted him like a pretzel. Kneeling on his parlor carpet, he contorted himself into excruciating positions to demonstrate what they had done to him.

"I kept begging them for water and they would spray something on my face, so I had to lick the drops," the 47-year-old officer told me several weeks after his release. "They covered my face and told me they put a snake and a scorpion on my neck. I thought I was going to die, but they were always laughing, like it was a joke."

As I listened to him, the stories from that Chilean summer 15 years ago came rushing back. Once more, I tried to reconcile conflicting images -- the liberating mission of American troops who drank tea with welcoming village elders, and the sadistic practices apparently flourishing in dark, secret cells.

Few Americans will ever meet a survivor of torture, and many may find it almost impossible to believe what they read about abuses committed by U.S. troops -- about the shy Afghan taxi driver who died in American custody after being hung by the wrists, choked in a hood, and forced to roll back and forth kissing his captors' boots; the Iraqi detainees at Abu Ghraib prison who were piled into naked tangles, photographed on leashes, threatened with snarling dogs and mock electrocution.

I can understand why there has not been more public outrage over these abuses. When an elusive enemy bombs the London transit system, when American troops are being shot out of the sky in Afghanistan, when diplomats are being assassinated and aid workers beheaded in Baghdad, we are all filled with impotent rage. We want to lash out, to punish, to get even. We want madness stopped and murderers caught.

If some interrogator in a dark corner of the war on terror is squeezing a prisoner who might be an Islamic terrorist a little harder right now, we don't really want to know about it. If coercion or intimidation can prevent a future bombing, break up a suicide cell, save a hundred innocent lives, is it not a necessary evil?

Yes, possibly, under extremely limited conditions. But studies have shown that building trust and dependence is a far more reliable way to break resistance, while humiliation always hardens hatred and pain often produces desperate lies. Moreover, once we accept the controlled, professional use of "exceptional measures" to interrogate a few hardened fanatics, it can be a short and slippery slope to a generalized climate of absolute power and swaggering license in which untrained guards are permitted to abuse and humiliate prisoners for sport or revenge.

The consequences can also resonate far beyond the prisons, damaging societies in ways that can be long-lasting and insidious. Stretching laws to permit abusive treatment of prisoners, employing doctors to probe the limits of pain, finding exceptional justification for practices routinely condemned in other countries -- all this can corrode the moral authority of a government and the norms of a free society. That's what happened in Chile during its 17 years of dictatorship.

Before the military coup, Chile was known as an unusually law-abiding and democratic country in a continent of unstable, coup-prone republics. Its parliament included parties from ultra-conservative to communist, its presidents were elected peacefully, its judges and civil servants were respected; corruption was minimal and civic life was spirited.

Then came Sept. 11, 1973. Amid a rising tide of political and labor agitation, with a socialist president in office and the middle class terrified of a popular uprising, the army stepped in, vowing to extirpate communism from Chilean soil. Many people were grimly grateful for the respite from democracy run amok. Legislators went home, judges accommodated military demands and respectable citizens turned away when long-haired youths were dragged into unmarked cars.

Within months the left was virtually exterminated, but the abuses continued. Thousands of people were detained, tortured and killed by the military and secret police. In the process, a culture of fear, mistrust and denial replaced a tradition of freedom and debate. The resulting rifts -- among neighbors, colleagues, even families -- were so bitter that only now, 15 years after the return to civilian rule, is Chile beginning to reknit, face the truth and acknowledge its complicity in dictatorship. As a conservative politician acknowledged recently, "We all failed as a society."

I don't mean to push the analogy too far. Nobody is dragging American citizens off to clandestine dungeons; most detainees in U.S. custody are foreigners of alien tongue and faith, classified as "enemy combatants" and held on foreign soil. But while some may well be terrorists, others are luckless innocents or dupes, more victims than aggressors. More than 30 people have died in American custody overseas, and others have been secretly shipped to foreign countries long condemned by the U.S. government for practicing torture.

In Afghanistan, many prisoners and ex-prisoners I interviewed were illiterate villagers who had been manipulated and fed lies about the West, taught that its leaders sought to destroy their religion and that its women were prostitutes and devils. One young man literally shrank from me in his cell, covering his eyes and ears to protect himself from my contamination. I felt so sorry for him that I immediately apologized and left the room.

To interrogate a fanatical bomber is one thing. But to force a devout Muslim to masturbate or eat pork or bark like a dog only reinforces stereotypes of Western vulgarity and arrogance -- and aids the recruitment of religious insurgents willing to kill and die in places like Iraq.

Just as worrisome is the subtler numbing effect on American society when the idea of torture begins to seem acceptable, even normal; when it becomes euphemized as "extreme duress" or "coercive" interrogation and practiced by protagonists in TV dramas. It is easier for us to ignore when it happens to non-Americans far away and out of sight, but it still confronts us with a moral choice.

I don't think America is in immediate danger of losing its ethical compass and abandoning its principles. The military has investigated some of the most egregious known abuse charges; some lower-ranking perpetrators have been punished; senior administration officials repeatedly assert they do not condone torture. And yet in less than four years, we have already become a more belligerent, hardened, unapologetic culture, where the vehicle du jour is an imitation Humvee and critics of military policy or prison abuses find their patriotism called into question.

As long as there are American troops overseas, the nation must rally behind them and pray for their safe return. But if we hope to set an example for the world, to rob Islamic extremists of their ammunition for jihad -- to truly defeat terrorism -- we cannot do it by waging a dirty war in the shadows. As long as one hooded captive is screaming in a dungeon at America's behest, we are all participants in torture, and we are all its victims.

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Pamela Constable is a deputy foreign editor at The Post and co-author of "A Nation of Enemies: Chile Under Pinochet" (W.W. Norton).

Slippery slope? Chile enjoyed a reputation for dignity and democracy before a 1973 military coup opened an era of brutality. The country is still recovering; above, anti-Pinochet protesters in January 2000.