A man with no face stares at me from the corner of a room. He pleads for help, but I'm afraid to move. He begins to cry. It is a pitiful sound, and it sickens me. He screams, but as I awaken, I realize the screams are mine.

That dream, along with a host of other nightmares, has plagued me since my return from Iraq in the summer of 2004. Though the man in this particular nightmare has no face, I know who he is. I assisted in his interrogation at a detention facility in Fallujah. I was one of two civilian interrogators assigned to the division interrogation facility (DIF) of the 82nd Airborne Division. The man, whose name I've long since forgotten, was a suspected associate of Khamis Sirhan al-Muhammad, the Baath Party leader in Anbar province who had been captured two months earlier.

The lead interrogator at the DIF had given me specific instructions: I was to deprive the detainee of sleep during my 12-hour shift by opening his cell every hour, forcing him to stand in a corner and stripping him of his clothes. Three years later the tables have turned. It is rare that I sleep through the night without a visit from this man. His memory harasses me as I once harassed him.

Despite my best efforts, I cannot ignore the mistakes I made at the interrogation facility in Fallujah. I failed to disobey a meritless order, I failed to protect a prisoner in my custody, and I failed to uphold the standards of human decency. Instead, I intimidated, degraded and humiliated a man who could not defend himself. I compromised my values. I will never forgive myself.

American authorities continue to insist that the abuse of Iraqi prisoners at Abu Ghraib was an isolated incident in an otherwise well-run detention system. That insistence, however, stands in sharp contrast to my own experiences as an interrogator in Iraq. I watched as detainees were forced to stand naked all night, shivering in their cold cells and pleading with their captors for help. Others were subjected to long periods of isolation in pitch-black rooms. Food and sleep deprivation were common, along with a variety of physical abuse, including punching and kicking. Aggressive, and in many ways abusive, techniques were used daily in Iraq, all in the name of acquiring the intelligence necessary to bring an end to the insurgency. The violence raging there today is evidence that those tactics never worked. My memories are evidence that those tactics were terribly wrong.

While I was appalled by the conduct of my friends and colleagues, I lacked the courage to challenge the status quo. That was a failure of character and in many ways made me complicit in what went on. I'm ashamed of that failure, but as time passes, and as the memories of what I saw in Iraq continue to infect my every thought, I'm becoming more ashamed of my silence.

Some may suggest there is no reason to revive the story of abuse in Iraq. Rehashing such mistakes will only harm our country, they will say. But history suggests we should examine such missteps carefully. Oppressive prison environments have created some of the most determined opponents. The British learned that lesson from Napoleon, the French from Ho Chi Minh, Europe from Hitler. The world is learning that lesson again from Ayman al-Zawahiri. What will be the legacy of abusive prisons in Iraq?

We have failed to properly address the abuse of Iraqi detainees. Men like me have refused to tell our stories, and our leaders have refused to own up to the myriad mistakes that have been made. But if we fail to address this problem, there can be no hope of success in Iraq. Regardless of how many young Americans we send to war, or how many militia members we kill, or how many Iraqis we train, or how much money we spend on reconstruction, we will not escape the damage we have done to the people of Iraq in our prisons.

I am desperate to get on with my life and erase my memories of my experiences in Iraq. But those memories and experiences do not belong to me. They belong to history. If we're doomed to repeat the history we forget, what will be the consequences of the history we never knew? The citizens and the leadership of this country have an obligation to revisit what took place in the interrogation booths of Iraq, unpleasant as it may be. The story of Abu Ghraib isn't over. In many ways, we have yet to open the book.

The writer served in the Army from 1995 to 2000 as an Arabic linguist and worked in Iraq as a contract interrogator in early 2004. His e-mail address iserictfair@comcast.net.