Pol Pot's former deputy is a man who enjoys a good joke. "Good humour is in my nature," he told me. "I have no worries."
Nuon Chea, known as Brother Number Two, served as Pol Pot's ideologue and loyal lieutenant for more than 30 years. He lives with his wife and grandchildren in a traditional wooden house on stilts near Cambodia's border with Thailand. Now 76, he looks well and his mind remains sharp.
He is the former deputy general secretary of Cambodia's Communist Party - known to the outside world as the Khmer Rouge. He is the most senior surviving member of the regime that governed during the time of the killing fields. Pol Pot - Brother Number One - died in 1998, when the Khmer Rouge finally collapsed after fighting a 20-year rebellion in the jungles of northern Cambodia.
Nuon Chea displayed no remorse when we discussed his role in the deaths of 1.7 million people - nearly a quarter of the Cambodian nation. During our meeting he was often chuckling, and boasted: "I have never stayed awake at night or shed any tears." He said he would fear no trial for war crimes or genocide. "I want to be clean, I want to show my people that I am a good man," he declared without irony.
Nuon Chea now has reason to be confident. While Slobodan Milosevic was brought to the dock amid fanfare at The Hague, the United Nations announced that it was abandoning attempts to establish a war crimes tribunal for Cambodia. It is now unlikely that more than a tiny few of the men responsible for the carnage of the killing fields will be brought to account.
The decision of the United Nations to withdraw from Cambodia follows several years of bickering with Prime Minister Hun Sen, who has insisted on maintaining control over the legal process. One of the main sticking points was the refusal of the Cambodian government to allow international law to override national legislation, particularly in respect to an amnesty granted to Ieng Sary, the former Khmer Rouge foreign minister.
The problems that have thwarted attempts to bring Pol Pot's henchmen to justice represent the first significant setback to the process of establishing ad hoc tribunals, which began in former Yugoslavia and continued in Rwanda and now Sierra Leone.
These tribunals appeared as part of a formidable trend towards a system of international justice where despots and tyrants could no longer shelter behind the protection of national sovereignty. The permanent International Criminal Court, first proposed in 1998, will become a standing reference point for all such cases if it is ratified by 60 nations.
Unless, that is, Washington has its way. The Bush administration looks ready to obstruct the workings of the proposed court. An amendment before Congress - the American Servicemembers' Protection Act - forbids Americans from co-operating with the court and authorises "any necessary action" to free any American soldiers who may be held in custody by the court.
Meanwhile, at The Hague, Milosevic has accused those behind the ad hoc tribunals of applying a "victor's justice". He has a point: while the legal proceedings might be impartial, these courts apply justice only when it suits the political needs of the major powers.
In 1995, Milosevic was presented as a world statesman and peacemaker at Dayton, Ohio, during the signing of the accord that ended the wars in Bosnia and Croatia. Yet the indictments that will probably convict him refer to atrocities that occurred prior to Dayton and of which western nations were fully aware. Why was he not indicted earlier? Because he was considered politically useful by the same governments that seek his prosecution today.
Milosevic was indicted only when Nato provided the international prosecutor with detailed evidence, including aerial photographs and radio intercepts, that established a case against him. It was not a coincidence that this happened during the bombing of Yugoslavia in June 1999 - at a time when support for the Kosovo war was waning in some Nato countries.
In Cambodia's case, any trial before an international court could trigger a re-examination of the country's past that may embarrass more than the Khmer Rouge. Nuon Chea would claim that, although many died of starvation during his rule, the most culpable murderer was the then US secretary of state, Henry Kissinger. In 1970, the US orchestrated a coup to overthrow Cambodia's king and establish a pro-American military regime. Kissinger ordered the secret bombing of Cambodia, killing hundreds of thousands of civilians.
Then there were the deals struck under the auspices of the United Nations to bring peace to Cambodia. Khmer Rouge leaders were treated as statesmen at the Paris peace accord meetings in 1991. Cambodia's agonising civil war finally ended after amnesties were offered to Khmer Rouge soldiers who had been encouraged to desert.
Why did the world not arrest Pol Pot, Nuon Chea and their accomplices earlier? For a decade after the killing fields were discovered, the UN recognised the Khmer Rouge as part of the legitimate government of Cambodia. The present king, Sihanouk, was their ally for 20 years. China armed the Khmer Rouge throughout the 1980s, despite full knowledge of the mass killings.
The Royal Thai Police guarded and controlled Pol Pot's movement until his death. At one time they escorted Pol Pot, wearing Hawaiian shirt and sunglasses, to the beaches on Thailand's southern coast. Why? He was useful as a stick to threaten the Cambodian government, which was backed by rival Vietnam.
Today, the United States divides the world into those who are with America and the "evil axis" opposing it. But as John Lloyd pointed out in this magazine recently, the US is so dominant "that unilateralism makes more sense than multilateralism". This allows the world's only superpower to conduct its wars - like the one in Afghanistan - without reference to international institutions. America has the power to impose its definition of terrorism - and of war crimes - upon the outside world.
It is hard to imagine Washington recognising the legitimacy of a court that might garner enough evidence to issue a warrant for the arrest of, for example, the Israeli prime minister, Ariel Sharon, on war crimes charges.
Nuon Chea shares Milosevic's opinion that ad hoc war crimes tribunals represent "victor's justice". He has kept faith with a Marxist analysis of power structures: "When they win, they are in power and they define right and wrong their way. That's life," he mused.
Perhaps there is more truth in what Nuon Chea is saying than we should be comfortable with.
Philip Rees's exclusive interview with Nuon Chea will be shown in BBC2's Correspondent on Sunday 17 March at 7.15pm