Torture is evil and unacceptable. Everybody, including even President Bush, agrees on that. But then comes a long list of buts. When it comes to America, the list is depressingly familiar - how to define torture; what the President can authorise; who can do what, where, and who to.
Meanwhile, less noticed, the seemingly virtuous British Government is doggedly chipping away at the international ban. Its policy of deliberate ambiguity on the issue is immoral, illegal and dangerous. Astonishingly, the Government seems to believe no one will notice.
This month's Queen's Speech looks set to contain legislation allowing national security to be weighed against concerns about torture. This would make it possible to send people back to countries where they risk torture - an extraordinary development in 21st-century Europe. More extraordinary still is the insistence that nothing in British attitudes has really changed.
Last year, the law lords ruled unanimously against the use of torture evidence in British courts; Lord Bingham, the senior law lord, was "startled, even a little dismayed" that the Government could attempt to ignore its international obligations. Far from showing deference to the judges' concerns, the Government is now, with touted new legislation, taking things one step further, to get past the judges' concerns. If Parliament approves the measure, Britain will be in plain violation of international law.
Britain still portrays itself as being on the side of the anti-torture angels. It puts money into confronting it worldwide, with publications like the Torture Reporting Handbook. It has campaigned for governments to sign up for additional commitments under the terms of the UN convention, including a global system of monitoring conditions for detainees.
So far, so admirable. At the same time, however, the Government faces quite the other way. It argues that the absolute ban on returning somebody to the risk of torture is unnecessary or worse. To the Home Secretary John Reid, the ban is wrong. "No ifs. No buts. It's just plain wrong." The prohibition against torture would be meaningless if governments could get around it simply by sending a suspect to be tortured elsewhere.
There is no question that the terror threat in Britain is real. But the way to defeat it is through good police and intelligence work, not through setting aside our core values. Opening the door to torture aids the terrorists' cause. It alienates British Muslims, whose co-operation with the police and security services is crucial to successful counter-terrorism efforts. And it damages Britain's standing at home and abroad, undermining its global anti-torture work.
British ministers seem to have reached a different conclusion. Britain is hell-bent on getting rid of a key 1996 judgment in the European Court of Human Rights. The Chahal judgment enshrines the ban on return to the risk of torture, without exception. But the Government is intervening in the case of an Algerian, Mohammed Ramzy, to persuade that court to create a national security exception that would allow it to deport terrorism suspects known to be at risk of torture if returned. Reid claims that those who defend the Chahal judgment "just don't get it".
The Prime Minister tells us that "the rules of the game are changing". Well, yes; clearly so. Britain is forcing through its policy of "diplomatic assurances" - implausible and unenforceable promises by governments with a track record of torturing people. These governments are asked to sign memorandums of understanding where they agree that (in this particular case, because the British Government asks them so very nicely), they will not torture. Such promises have in the past been proved as empty as one might expect - not least because exposure of the broken promise would be in the interest of neither side.
The diplomatic-assurance deals do not stand up to serious scrutiny. If a country doesn't torture, the agreement isn't needed. If a country does torture, a one-off agreement will not stop it. Manfred Nowak, UN special rapporteur on torture, and Louise Arbour, UN high commissioner for human rights, are among those who have sharply criticised the British plans.
One might hope that ministers would take note of such voices. Instead, they lash out at Nowak and others for allegedly failing to "look at human rights in the round". And yet, the British Government refuses to see things in the round. It has repeatedly refused to introduce measures - such as the use of phonetap evidence in court, as advocated by senior police officers, which could make it easier to prosecute terror suspects successfully. Meanwhile, it refuses to criticise Washington for policies which have so spectacularly opened the door to torture in recent years.
Britain even seeks to whitewash the documented cases of torture that we have seen, claiming for example that the abuses at Abu Ghraib were merely a case of "bad apples". It has failed, too, to challenge Washington on renditions, or the policy of "disappearing" terror suspects.
The ban on returning people to the risk of torture is absolute. By denying that truth, the Government does not protect us from further attack. On the contrary. When governments seek to persuade themselves and others that laws no longer matter, that is dangerous for us all.
The writer is UN advocacy director of Human Rights Watch