From After the Killing Fields: Lessons from the Cambodian Genocide, by Craig Etcheson (Texas Tech U. Press, 2006), p. 78 (footnote references omitted):
Were the Cambodian people somehow Pol Pot’s “willing executioners,” with the violence of the Khmer Rouge regime reflecting an underlying cultural trait of the Cambodian people, historically unique to the time and place it occurred? Or did the violence of the Khmer Rouge regime emanate from some more broadly distributed ideological origin, therefore rendering it amenable to comparison? Perhaps the Khmer Rouge mass killing arose from the same tenets of communism that brought about the mass killing of Stalin’s Russia and Mao’s China but that was, by absolute numbers, much less evil. Or perhaps the killing in Cambodia can be understood as a response to the perceived threat from Vietnam, as the Khmer Rouge themselves have argued at some length. These same themes and issues lay at the heart of the Historikerstreit, and they also are part and parcel of genocide studies.
In the scholarly literature on the Khmer Rouge regime of Democratic Kampuchea, there have been two principal schools of thought regarding the nature of the violence that took so many lives in such a short period of time. One school of thought holds that the primary locus of the violence was local and that it was largely the result of the spontaneous excesses of a vengeful, undisciplined peasant army. A prominent proponent of this school of thought is Michael Vickery. A second school of thought holds that the locus of the violence was centralized and that it was largely the result of a carefully planned and centrally controlled security apparatus. Several observers have proposed this explanation of the violence in the Democratic Kampuchea regime, including, for example, the recently retired U.S. ambassador to Cambodia, Kenneth Quinn. It can be argued, however, that until recently there was an inadequate amount of data to make an unambiguous determination on this question.
A wide range of new evidence uncovered by the Documentation Center of Cambodia over the course of the last ten years has done much to resolve this controversy. In particular, data on the frequency, distribution, and origin of mass graves, combined with data gleaned from newly discovered Khmer Rouge internal security documents, have given us new insight into the question of the economy of violence within Democratic Kampuchea. The data lead inexorably to the conclusion that most of the violence was carried out pursuant to orders from the highest political authorities of the Communist Party of Kampuchea. In this chapter I briefly review some of the new evidence that so strongly suggests this new and now well-documented conclusion.