During the presidential campaign, Donald Trump said he would bring back waterboarding, a form of torture that simulates drowning, and "a hell of a lot worse" as a tactic in America's war against terror.

It doesn't look like his stance on torture has softened since winning the election. "I want to keep our country safe...as far as I'm concerned, we have to fight fire with fire...we're not playing on an even field," he said, referring to the Islamic State, during an interview with ABC News.

Trump did say he will rely on the views of his officials, including new CIA director Mike Pompeo and Defence Secretary James Mattis, "and if they don't want to do [torture], that's fine, if they do want to do [it], we'll work toward that end".

But he added: "I want to do everything that you're allowed to do within the bounds of what you can do legally. But do I feel it works? Absolutely, I feel it works." Trump claimed his view is shared by senior intelligence officials, who he had asked if torture works.

The CIA was heavily criticised for its violation of human rights and international law, such as the Geneva Conventions to which the US is signed, in its use of torture during the years after 9/11. And there is little if any evidence to show that, leaving aside the moral issues around its use, torture works in practice.

Some of the problems with torture were summarised succinctly in a 2009 paper by Mark A. Costanzo of Claremont McKenna College and Ellen Gerrity of Duke University, titled The Effects and Effectiveness of Using Torture as an Interrogation Device: Using Research to Inform the Policy Debate, and published in the journal Social Issues and Policy Review.

"Governments that allow for the use of torture typically argue that it is used in a precise, strictly controlled manner," said the paper's conclusion. "But scholars have found that once torture is authorised, its use is very difficult to contain...Although torture does not produce reliable information, it may persist because it satisfies psychological needs in times of stress. Specifically, it counters a sense of desperation, reassures interrogators that they are in control, and bestows a feeling of empowerment, at least in the enclosed world of the interrogation room."

In any case, a lot of the conversation and rhetoric around torture – as though it is just a cold, functional interrogation device – disguises the horror of what it means for those subject to it.

Not only is its effectiveness unproven, but its dark violence means that for many people, it is morally unjustifiable regardless of whether it works. Here are some harrowing accounts of what torture really means in practice.

'I had skin hanging off me and bruises and cuts all over me'

Ridha al-Najjar is a Tunisian picked up in Pakistan by the CIA in 2002 as it prowled the world in search of those responsible for 9/11. He was detained and tortured by the CIA at an infamous "black site" known as Cobalt in Afghanistan. Najjar, who was held until 2015 on vague suspicions of terrorist activities, but never charged or tried, described his experience of CIA torture to Human Rights Watch.

Al-Najjar said he was forced to hang from the bar repeatedly over the course of roughly his first three months at the Dark Prison. Each hanging session lasted up to 24 hours and happened frequently and repeatedly. During these sessions his arms would be chained above his head to a bar at the top of the room, making it impossible to sleep. Sometimes he could touch the ground with his feet, sometimes with just his toes, and other times not at all. The captors would only take him down for interrogation sessions and other forms of torture, often by throwing him violently to the floor where they would sometimes beat and kick him. While his arms were chained to the bar, they beat him with a baton on his back and legs and also punched him in the chest, in the back, and in his kidneys. After one session, they took him to another room where he said they used bright lights to videotape and photograph his injuries. "I was a mess," he said. "I had skin hanging off me and bruises and cuts all over me."

Al-Najjar said his captors took him into a room with an "electric chair." It was made out of metal or iron, had plugs attached to wires for fitting on fingers, and a headset with wires. The description suggested make-shift apparatus, attached to a wall pipe. His US interrogators threatened during interrogations to use the chair on him, but never actually did. The room also contained other instruments used for torture, including a board that he believes his interrogators used on him on various occasions for different types of water torture, and a coffin in which they threatened to place him.

Source: Human Rights Watch

The US Senate Select Committee on Intelligence published a damning report on the CIA's use of "enhanced interrogation techniques", a bureaucratic euphemism for torture, in 2014. The report detailed what "enhanced interrogation techniques" meant in its brutal reality.

The waterboarding technique was physically harmful, inducing convulsions and vomiting. Abu Zubaydah, for example, became "completely unresponsive, with bubbles rising through his open, full mouth." Internal CIA records describe the waterboarding of Khalid Shaykh Mohammad as evolving into a "series of near drownings."

Sleep deprivation involved keeping detainees awake for up to 180 hours, usually standing or in stress positions, at times with their hands shackled above their heads. At least five detainees experienced disturbing hallucinations during prolonged sleep deprivation and, in at least two of those cases, the CIA nonetheless continued the sleep deprivation.

At least five CIA detainees were subjected to "rectal rehydration" or rectal feeding without documented medical necessity. The CIA placed detainees in ice water "baths." The CIA led several detainees to believe they would never be allowed to leave CIA custody alive, suggesting to one detainee that he would only leave in a coffin-shaped box...CIA officers also threatened at least three detainees with harm to their families – to include threats to harm the children of a detainee, threats to sexually abuse the mother of a detainee, and a threat to "cut [a detainee's] mother's throat."

Conditions at CIA detention sites were poor, and were especially bleak early in the program. CIA detainees at the Cobalt detention facility were kept in complete darkness and constantly shackled in isolated cells with loud noise or music and only a bucket to use for human waste.

Lack of heat at the facility likely contributed to the death of a detainee. The chief of interrogations described Cobalt as a "dungeon." Another senior CIA officer stated that Cobalt was itself an enhanced interrogation technique.

At times, the detainees at Cobalt were walked around naked or were shackled with their hands above their heads for extended periods of time. Other times, the detainees at Cobalt were subjected to what was described as a "rough takedown," in which approximately five CIA officers would scream at a detainee, drag him outside of his cell, cut his clothes off, and secure him with Mylar tape. The detainee would then be hooded and dragged up and down a long corridor while being slapped and punched.

Throughout the program, multiple CIA detainees who were subjected to the CIA's enhanced interrogation techniques and extended isolation exhibited psychological and behavioral issues, including hallucinations, paranoia, insomnia, and attempts at self-harm and self-mutilation. Multiple psychologists identified the lack of human contact experienced by detainees as a cause of psychiatric problems.

Source: US Senate Select Committee on Intelligence report on CIA torture

Liam Holden was waterboarded by the British Army as a 19-year-old suspected of being involved in an IRA murder of a British soldier in 1972. He served 17 years in prison before having his murder conviction quashed as a miscarriage of justice.

After being led into the cubicle, he told the jury, he had been forced to stand spread-eagled against the wall before being punched in the stomach. Then, he said, the sergeant shouted for a towel and a bucket of water. A reporter from the Belfast Telegraph who was in court recorded what Holden said next: six soldiers held him down, the towel was folded over his face, and water was poured slowly from the bucket and through the towel, on to his face. "It nearly put me unconscious," Holden said. "It nearly drowned me and stopped me from breathing." This is said to have happened five or six times over the next couple of hours.

There were allegations of further mistreatment. At one point, Holden told the jury, he was hooded, taken from the school, and driven to the outskirts of the city, where he was told he was to be shot dead. He finally agreed to admit shooting Pte Bell, and was told that if he didn't sign a statement for the police at Castlereagh he would be brought back to the school for more of the same.

Source: The Guardian

Amid the war in Syria, Amnesty International has documented the horrifying experiences of torture by those held in the prisons of President Bashar al-Assad's forces. Assad is being supported against the various rebel groups in Syria by Russian President Putin. Trump has suggested a closer working relationship in Syria with Russia. Here is a small selection of the accounts of torture by Assad's forces.

They had me stand on the barrel, and they tied the rope around my wrists. Then they took away the barrel. There was nothing below my feet. They were dangling in the air. They brought three sticks... [They were] hitting me everywhere... After they were done beating me with the wooden sticks, they took the cigarettes. They were putting them out all over my body. It felt like a knife excavating my body, cutting me apart.

They beat me until I was lying on the ground and then they kicked me with their military boots, in the places where I have had my hip operations, until I passed out. When I woke up, I was back in the solitary cell – they had dragged me back there from that room – but my trousers had been opened and moved down a bit, my abaya [full-length robe] was open and my undershirt was moved up. Everything was hurting, so I couldn't tell if I had been raped. It was overwhelming pain everywhere.

I realised that my friend was in the same cell. He was blindfolded and covered in blood. He had told them that my father and brother had been helping the armed groups, which was not true, and that I had gone to demonstrations. I was annoyed with him at first but then I forgave him when I understood the pain that he went through... He told us that they had taken him and his mother. He apologised to us: 'I was tortured, so I said your names.'

The guard laid me down on my stomach. He tied my legs to a stick with a rope, and lifted up my feet. The beating was focused on the bottom of my feet. He struck me around 35 to 40 times... For the first 10 strikes I felt the pain. Then all the feeling left my body. I went out of my body. After the beating was done, my feet swelled to a huge size. It was unimaginable. They didn't look like feet any more. I couldn't stand. I felt I would fall over. They made me jump from one foot to the other foot. This made the blood go back into my feet, so that I could feel the pain again. Then they started again. The second time was the worst, much worse than the first time.

Source: Amnesty International

In 2008, at the time there was a debate in the US as to whether waterboarding should really be considered torture, the late journalist Christopher Hitchens was himself waterboarded as an experiment. He wrote an eloquent piece for Vanity Fair titled: Believe Me, It's Torture.

You may have read by now the official lie about this treatment, which is that it "simulates" the feeling of drowning. This is not the case. You feel that you are drowning because you are drowning — or, rather, being drowned, albeit slowly and under controlled conditions and at the mercy (or otherwise) of those who are applying the pressure. The "board" is the instrument, not the method. You are not being boarded. You are being watered. This was very rapidly brought home to me when, on top of the hood, which still admitted a few flashes of random and worrying strobe light to my vision, three layers of enveloping towel were added. In this pregnant darkness, head downward, I waited for a while until I abruptly felt a slow cascade of water going up my nose...I held my breath for a while and then had to exhale and—as you might expect—inhale in turn. The inhalation brought the damp cloths tight against my nostrils, as if a huge, wet paw had been suddenly and annihilatingly clamped over my face. Unable to determine whether I was breathing in or out, and flooded more with sheer panic than with mere water, I triggered the pre-arranged signal and felt the unbelievable relief of being pulled upright and having the soaking and stifling layers pulled off me. I find I don't want to tell you how little time I lasted.

Hitchens concluded:

I apply the Abraham Lincoln test for moral casuistry: "If slavery is not wrong, nothing is wrong." Well, then, if waterboarding does not constitute torture, then there is no such thing as torture.

Source: Vanity Fair