By Matt Frei
BBC News, Washington
The first time I came across the concept of water-boarding was in Cambodia in 1996.
Water-boarding was used by the Khmer Rouge in Cambodia
I was on a visit to Tuol Sleng, the school that had been turned into a concentration and liquidation camp by the Khmer Rouge in the 1970s.
It was situated, oddly, right in the heart of the capital, Phnom Phen.
I met one of the seven people - out of about 23,000 - known to have left the camp alive.
He was a sculptor and he was saved because he was particularly good at depicting the smile of Brother Number One, Pol Pot.
He took me on a tour of the camp, where most of his friends and seven members of his family were butchered.
In one room, there was a small painting, barely noticeable amongst all the skulls, bones, chains and hammers.
It was a naive drawing of a man strapped to a plank, a board, if you like, with another man pouring water over his face with a metal watering can. The kind you use for watering flowers.
The face of the man lying down was covered in a blue cloth. The painting looked fairly comical, as if someone was irrigating a human face.
"Water torture," my friend explained. "You think you die."
The Khmer Rouge were fast workers. In only a few years they managed to kill one quarter of Cambodia's population with a mixture of execution and starvation.
But like others who butchered in the pursuit of utopia, they borrowed heavily from the past. Water-boarding was not their invention. The Spanish Inquisition used it and called it the toca.
The Dutch East India Company used it in the massacre of Amboyna in 1623.
For much of history, water-boarding has been to torturers what cream is to apple pie. They go hand-in-hand.
So, it seems odd that the United States is in the middle of a lively debate about whether water-boarding is an "enhanced interrogation technique", as the CIA insists on calling it, or torture.
Of course it is the latter, any hooded member of the Spanish Inquisition or executioner at Tuol Sleng could have told you that.
I interviewed Richard Armitage, the former US deputy secretary of state, the other day. A most affable man with a sharp mind and a quick tongue, he is the only person I have ever met who has actually been water-boarded.
Former official Richard Armitage was water-boarded in military training
It was part of his military training - he was a graduate of a US military programme called SERE (Survival, Evasion, Resistance and Escape).
"Of course water-boarding is torture," he said bluntly. "I can't believe we're even debating it. We shouldn't be doing that kind of stuff."
So here is the tricky part. Water-boarding has worked in some notorious cases.
It is said to have made Abu Zubaydah, the first high level al-Qaeda officer captured after 9/11, squeal.
It is said to have made Khaled Sheikh Mohammed, the alleged mastermind of 9/11, talk.
But how often was it used on people who had nothing to say? Has it ever killed any of those it was used on? We do not know for sure.
The CIA may not be the right organisation to tell us. They have, after all, just admitted to destroying hundreds of hours of video-taped interrogations in which water-boarding was used.
Water-boarding is said to have been what made Abu Zubaydah talk
Of what we can be more certain is that the enhanced interrogation technique has enhanced hatred of America.
The debate should not be about whether water-boarding is torture or not. It is.
Just listen to the description of the French journalist Henri Alleg, who was water-boarded by the French military during the Algerian War.
"I had the impression of drowning, and a terrible agony, that of death itself, took possession of me," he wrote.
"My body struggled uselessly to save me from suffocation. The fingers of my hands shook uncontrollably. 'That's it! He's going to talk!' said a voice."
Sounds like torture, doesn't it?
No, if the debate is to be honest it should be about whether torture is allowed in certain circumstances.
If water-boarding stopped another 9/11 from happening, the vast majority of Americans would probably be in favour in those special cases.
The trouble is, we never know if it is a special case until we have finished the torturing and even then we cannot be sure.
Torture becomes like an addiction, with uncertain results, that defiles the torturer as much as it haunts the tortured. The cost-benefit ratio is out of kilter.
Which is why the administration has already supplied the answer to a question that America should not even be asking. We do not torture.
Time to practice what you preach... just ask my friend from Tuol Sleng.
Matt Frei is the presenter of BBC World News America, airing at 2300 GMT (1900 ET / 1600 PT) every weekday
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