PHNOM PENH, Cambodia — The first trial to showcase the atrocities of the Khmer Rouge three decades ago concluded with the regime’s chief torturer still seemingly unable to grasp the magnitude of his actions. Yet despite that surprising end, the trial may have helped Cambodia begin to move beyond the horrors of its past...

... The case broke new ground as a hybrid of national and international justice systems with the support of the United Nations. In another innovation, it included the participation of some victims as “civil parties” represented in court by their own lawyers.

After a slow start, the trial began to draw the attention of a nation that for the past three decades has mostly hidden from the traumas of the Khmer Rouge years. Coinciding with the trial, a new textbook about the Khmer regime began distribution to the high schools, breaking a silence in the education system that has contributed to widespread ignorance.

Human rights groups and legal experts said they hoped the trial would act as an example to help reform Cambodia’s corrupt justice system and erode a culture of impunity, in which powerful people often act beyond the reach of the law.

“The Duch trial itself proceeded methodically and, in the end, was a success,” said Alex Hinton, director of the Center for the Study of Genocide and Human Rights at Rutgers University. “Duch received the fair trial his victims never had.”...