By Paul Reynolds
World affairs correspondent, BBC News website
Protest against water-boarding in Washington
The latest revelations about CIA interrogations have put the advocates of coercive techniques onto the defensive.
The argument over such methods, especially "water-boarding", has raged since 9/11 as the Bush administration has fought to preserve what it regards as an effective way of getting information from al-Qaeda suspects.
Critics say the techniques are torture under both US and international law and should be banned.
The UN Convention on Torture defines torture as "any act by which severe pain or suffering, whether physical or mental, is intentionally inflicted on a person..." in order to get information.
The debate has been heightened by an ABC News interview with ex-CIA officer John Kiriakou, who said he took part in interrogating al-Qaeda prisoner Abu Zubaydah. He acknowledged that water-boarding, used in that case, does amount to torture.
It is now also known that in 2005 the CIA destroyed hundreds of hours of videotapes showing the interrogations of Abu Zubaydah and another al-Qaeda prisoner.
The legal state of play
The Bush administration accepts that torture is banned by US and international law and says it does not practise it.
However, the United States has not outlawed so-called "enhanced interrogation" techniques because the administration does not include enhanced interrogation in its definition of torture.
The "enhanced" techniques include not only water-boarding but sleep deprivation, subjection to cold and long periods of standing and some slapping.
Water-boarding involves a prisoner being stretched on his back, having a cloth pushed into his mouth and/or plastic film placed over his face and having water poured onto his face. He gags almost immediately.
CIA officials have been quoted as saying that water-boarding has been used on three prisoners since 2001 but on nobody since 2003.
CIA and water-boarding
The CIA Director Michael Hayden, who took office in May 2006, is reported to have discontinued water-boarding, but has refused to confirm that publicly. However, he did say in a recent interview: "It would be wrong to assume that the programme of the past is necessarily the programme moving forward into the future."
Congressional leaders have proposed a clause banning water-boarding in a bill to finance intelligence operations.
Difference between CIA and armed forces
The enhanced or coercive techniques, water-boarding included, are confined to the CIA. The US armed forces are not allowed to use them.
This was made clear in 2006 in a new army manual. It banned torture and degrading treatment of prisoners, including water-boarding, forced nakedness, hooding and sexual humiliation.
The manual's publication followed the passing of the Detainee Treatment Act in 2005, which prohibited the "cruel, inhuman, or degrading treatment or punishment" of detainees.
The president's order excluded the CIA
The CIA exclusion from all this was outlined in an executive order signed by President Bush in July 2007. This sought to define the American commitment to the Geneva Conventions' prohibition on cruel, humiliating and degrading treatment and torture.
The presidential order defined torture by reference to the US legal code. The code says it is an action "specifically intended to inflict severe physical
or mental pain or suffering".
John Kiriakou: "We probably shouldn't be ... doing this"
The order ruled out the use of torture as defined by the legal code and also listed other interrogation methods and practices that were not allowed.
These range all the way from murder and rape to acts of humiliation.
The banned methods did not however include the so-called enhanced interrogation techniques.
The order stated that the CIA was allowed to conduct a special "program of detention and interrogation".
An accompanying memorandum from the president is said to have listed the allowable methods, but this has not been made public.
Debate goes on
The argument is not over. Mr Kiriakou concluded: "Water-boarding is probably something that we shouldn't be in the business of doing. We're Americans, and we're better than that."
But he accepted that Abu Zubaydah had given up during water-boarding and had provided information he had previously refused to give (Abu Zubaydah later claimed he had made things up).
The issue dominated the congressional hearings this year into the appointment of Michael Mukasey as the new US Attorney general. He called water-boarding "repugnant to me" and promised a review of its use.
In 2006, Vice-President Cheney defended water-boarding.
Asked on a radio programme whether "a dunk in water is a no-brainer if it can save lives?" he replied: "Well, it's a no-brainer for me, but for a while there I was criticised as being the vice-president for torture. We don't torture."
On the other hand, Senator and Republican presidential candidate John McCain, who was tortured by the North Vietnamese as a prisoner of war, has said that water-boarding is torture: "It no different than holding a pistol to his head and firing a blank."