No one who has visited Tuol Sleng will ever forget it. Once a high school in the suburbs of Phnom Penh, it has been left exactly as it was found in 1979, when Cambodia's murderous Khmer Rouge were driven out.
The classrooms were turned into torture cells, and one or two blood-encrusted bedsteads, used to tie the prisoners down, are still in place. The upstairs walkways were caged in with barbed wire, the guidebook explains, to prevent inmates cutting their agony short by throwing themselves head-first on to the concrete below. Up to 20,000 people, most of them Khmer Rouge cadres who had fallen under suspicion, entered prison S-21, as Tuol Sleng was designated. No more than seven emerged alive.
Tuol Sleng, however, is merely a microcosm of what happened in Cambodia the late 1970s. During less than four years in power, the Khmer Rouge killed some 1.7 million Cambodians, roughly a quarter of the population, in an act of auto-genocide which dwarfs Mao's Great Leap Forward or Stalin's murder of the Kulaks. Nobody was tried for those crimes, and until recently it seemed that no Khmer Rouge leader would ever find himself in court. Pol Pot, the former "Comrade Number One", died in a jungle camp in 1998, deposed by his own movement but untouched by outside justice.
But now, 26 years after Pol Pot declared "Year Zero", it appears that someone may be made to take responsibility for the slaughter after all. Under international pressure, Cambodia is preparing a law which would enable surviving Khmer Rouge leaders to be tried for crimes against humanity. The process needs United Nations approval, and may take months to get started, but the Phnom Penh government is holding two highly deserving candidates for exemplary justice – the former commander of S-21, Kang Kek Ieu, known as "Duch", and Ta Mok, the one-legged Khmer Rouge commander known – with reason – as "The Butcher", who led what was left of the movement until its final collapse in 1999.
Duch is reported to have become a born-again Christian since his days in charge of S-21 (a memo survives in which a guard asked him what to do with nine boys and girls in his custody. His written reply: "Kill them all."), and is said by his lawyer to be eager to tell the courts and the people about "the truth of the Khmer Rouge regime". The Phnom Penh government, consciously or unconsciously invokingSouth Africa's celebrated Truth and Reconciliation Commission, says that the process will help to bring "peace and reconciliation".
There are still many obstacles to a trial, not least the opposition of the Chinese, who supported the Khmer Rouge throughout. But with Slobodan Milosevic in the dock in The Hague, and courts in Europe and Africa dispensing justice to the perpetrators of the Rwandan genocide, we seem at last to be living in an era in which potential dictators and their accomplices have reason to fear that they will not escape with impunity.
Why, then, does what is happening in Cambodia arouse so much caution, not to say cynicism? There are several reasons, not least of which is the government's motives. Hun Sen, who has effectively been in power since 1985, is himself a former Khmer Rouge cadre who seems less interested in repudiating the movement's philosophy than in punishing certain former comrades. Duch and Ta Mok's main crime appears to be that they held out to the last: they are the only former Khmer Rouge figures still in custody. Others who surrendered earlier are not only at liberty, some are serving in Mr Hun Sen's government.
Nor has the international community much cause to trust the Prime Minister. In 1993, at a cost to the rest of the world of some $2bn, the UN sent peacekeepers and administrators into Cambodia to organise the freest election the country has ever seen. Despite much intimidation by his supporters, Mr Hun Sen came second to King Sihanouk's son, Prince Ranariddh, and formed a coalition with him. He never relinquished effective power, though, and ditched his unwanted partner as soon as the world's back was turned.
Since then the former cadre, still barely 50, has been improving his golf handicap and taking an interest in the business deals on offer to a country with tempting natural resources. Tellingly, he warned this week that a Khmer Rouge trial might not only reignite civil war, but "will create concern for investors".
Phnom Penh has successfully resisted the UN's attempts to insist that the trials should be held outside Cambodia, and there may be some sympathy for the argument that if anyone has the right to witness justice being done, it is the survivors of the killing fields. There is a certain uneasiness too about hauling defendants out of their own society to be tried in another; even more so if it is to another culture entirely. Earlier this year I watched as four Rwandans, including two nuns, were tried (and later sentenced to long prison terms) in Belgium for their part in mass murder thousands of miles away, and wondered whether any cause had been served but the alleviation of Belgian colonial guilt.
That is not the only concession by the UN, however. It has also agreed that only two of the five judges on the panel will be international, making it even more likely that the process will be subject to manipulation. As for the implication that such a trial would mirror South Africa's reconciliation process, that is absurd. The Truth and Reconciliation Commission, or TRC, depended hugely on the moral authority of its inventor, Archbishop Desmond Tutu. There is nobody of the same independent stature in Cambodia – certainly not King Sihanouk, who with his son has been thoroughly tamed by the Prime Minister.
Yet the TRC itself was not the all-encompassing miracle so many people outside South Africa take it to be. In the interests of truth and reconciliation, many had to forgo justice; not everyone was happy to see their husband or son's killer obtain immunity in exchange for testifying. Some, like the former president, PW Botha, refused to appear and got away with it. The sessions I attended, on South Africa's chemical and biological warfare programme, never heard from the mastermind, Dr Wouter Basson. The commission did not go back to the origins of apartheid, and was subject to a deadline which gave it no hope of examining all the wrongs committed in the name of the ideology. The TRC, in short, was a messy compromise of the sort that has to be made in the aftermath of great crimes, something the negotiators on Northern Ireland will have to come to terms with. Unlike Ulster, South Africa or even Rwanda, however, there was no element of inter-communal enmity in Cambodia. The country tore itself apart on ideological lines, and the psychological damage is evident to anyone who has been there. It may be that almost any form of accounting for the past turns out to be better than nothing, which is what Mr Hun Sen might prefer if it served his purposes.
Again, Tuol Sleng illustrates the point. Next to the former school buildings where the Khmer Rouge consumed so many of its own, a visitors' centre has been built to detail the crimes of the regime. The final display is a map of Cambodia – made up of the skulls of the victims. It conveys an unintended message: that this is still far from being a normal society.