Mass grave at the Killing Field of Choeung Ek, Cambodia, by akturer

Fifty years ago on 17 April 1975, the Khmer Rouge captured Cambodia’s capital, Phnom Penh. Led by Pol Pot, the movement sought to create a Maoist, rural society. Under the regime, around two million people are thought to have died, including by execution and forced labour.

Though the Khmer Rouge’s time in power ended in 1979, it wasn’t until 2018 that a trial, the Extraordinary Chambers in the Courts of Cambodia (ECCC), secured the convictions of three of the movement’s senior leaders for offences including crimes against humanity and genocide. By this point, Pol Pot himself had long since passed away.

The ECCC’s origins are found in the 1990s and the establishment at that time of international criminal trials, including in the former Yugoslavia and in Rwanda. Momentum was building towards the creation of a permanent court. Eventually, in 2002, this became the International Criminal Court (ICC).

The trial featured many months of witness testimony, including that of François Bizot, a French anthropologist who had been imprisoned by Duch in 1971. Duch’s trial was perhaps the most dramatic. ‘I bear moral responsibility before the souls of the dead for all the crimes,’ he told the courtroom as he took the stand.

Ultimately, Khieu Samphan, Nuon Chea and Kaing Guek Eav/Duch were all convicted by the ECCC. Ieng Sary passed away before his trial ended and Ieng Thirith was found to be unfit to stand. She passed away herself in 2015.

When assessing the Court’s success or failure, critics of the ECCC highlight its limited number of convictions. Cases number three and four against less senior leaders fell apart in 2021, for example. Tomas Hamilton is a barrister with G37 Chambers in London who worked at the UN Assistance to the Khmer Rouge Trials and led the defence team for one of the leaders. ‘It’s not so much about the absolute number of convictions,’ he says. ‘The conviction of one very senior person may speak volumes compared with a number of convictions of less senior participants. Those three convictions spanned three and a half years over a large number of geographic crime sites.’

Commentators believe there are other, longer-term contributions to take into account. For example, around a quarter of a million Cambodians – from farmers to monks – watched the proceedings as part of an unprecedented outreach programme. Ambassador David Scheffer was the key negotiator for the US and was instrumental in establishing and maintaining the ECCC as a UN special expert. ‘The ECCC holds the record for the most participation by a local population in the trial process – more than any other war crimes tribunal to date, an extraordinary legacy,’ he tells Global Insight.

The ECCC was a ‘hybrid’ court, a joint project between Cambodia and the international community, as embodied in the UN. Its unusual structure was a source of friction but also collaboration between the two. ‘The ECCC was not some neo-colonial idea. It was an “internationalised” national court. Through a process of dialogue and negotiation, we worked out what could be achieved domestically and where we needed an international overlay to ensure appropriate legal standards and keep everything as impartial as possible,’ explains Scheffer. ‘The court could not be a perfect court. But if you pursue the perfect, you sacrifice everything. What really needs to be pursued is credible justice, and that’s what we managed with the ECCC.’

Another product of this local approach was the role of the regime’s victims in the process. They were, for the first time in an international war crimes trial, given a voice during proceedings and participated as civil parties – although these were criminal proceedings. In trials one and two, over 4,000 victims were recognised and over 100 actively participated. ‘It was pioneering in some respects,’ says Hamilton, who is also the author of the book The Arms Trade and International Criminal Law. ‘Victims felt that they had a voice and a role to play as civil parties in the proceedings. Since then, the ICC has built on that model. Though there were no financial reparations at the ECCC, there were symbolic measures.’ Sara Elizabeth Dill is Co-Vice Chair of the IBA War Crimes Committee and agrees that ‘international criminal law can help establish a historical truth, giving survivors a voice.’

The ECCC ultimately cost over $350m. ‘The cost of tribunals is a frequent debate, especially when armed conflict utterly destroys the social and economic fabric of a nation,’ says Dill, who’s a partner at Anethum Global. ‘When millions are starving or lacking proper healthcare for months or years, it does raise the question of whether millions of dollars should be spent on courthouses and trials, or on rebuilding a nation and fostering peace and forward movement. Ultimately, I think that this decision, as with any decision on accountability, should be solely for the population of the nation recovering from armed conflict.’

Accountability, argue proponents of international criminal law, is key. In 2025 this may mean being called to account for one’s actions by the ICC. ‘If you commit a crime that falls within the jurisdiction of the ICC, you should not benefit from impunity,’ says Hamilton. ‘The ICC is there to demonstrate that there are certain prohibitions under international law, and they apply to everyone even if you are a powerful state.’