Book review: Timothy Williams. The Complexity of Evil: Perpetration and Genocide.

Timothy Williams. The Complexity of Evil: Perpetration and Genocide New Brunswick, NJ: Rutgers University Press, 2020. Paperback $43.95

In The Complexity of Evil: Perpetration and Genocide Timothy Williams draws from his training as a comparative political scientist and conflict scholar to construct what he terms the Complexity of Evil model. Aptly named, this model is an attempt to capture the complexity of why foot soldiers and low-level perpetrators participate in genocide. While not adding much new research to the field, his analysis and synthesis of the existing scholarship demonstrates a fresh attempt to amalgamate more than 70 years of perpetrator studies to better understand what drives genocidal action. Like others pioneers of comparative genocide research, such as Chalk and Jonassohn (1990), Robert Melson (1992), James Waller (2002), Scott Straus (2016), and Kjell Anderson (2018), among others, Williams’s study endeavors to highlight behavioral and contextual patterns during genocide to better understand how and why so-called ordinary people participate in genocide. The answer, unsurprisingly, is complicated.

Having mined a robust literature of perpetrators studies by historians, psychologists, philosophers, political scientists, geographers, anthropologists and more, Williams constructs a three-part model to determine what drives individual participation in genocide. This model, named in response to Hannah Arendt’s seminal book Eichmann in Jerusalem: A Report on the Banality of Evil, is built upon the premise that “individuals’ motivations to participate in genocidal action are indeed most often banal, but they are also manifold and complex” (3). To untangle this intricate web of motivations, Williams systematically differentiates between three influential mechanisms that inform a perpetrator’s actions, which he classifies as motivations, facilitative factors, and contexts. While little of this is groundbreaking, Williams’ approach is usefully organized and therefore a great resource for scholars seeking a structured approach to investigating low-level perpetrators.

This model articulates a dynamic network of possibilities that can be used to understand post-facto the psychological processes that perpetrators engage in. Firstly, he looks at motivations, which he defines as “a mechanism that guides a choice between action alternatives that are both socially structured and individually constructed” (212).  He further delineates these motivations into three categories: ingroup-focused motivations, outgroup motivations, and opportunistic motivations. And these three categories are further broken down into 15 subcategories, which are then further disentangled. As a result, the reader has access to decades of scholars’ answers (23 in total) to why people commit genocide all boiled down into one articulate chapter.

But this quantitative approach to motivations does leave something to be desired. For example, part of the reason why Arendt’s conclusion about the banality of evil was and is so powerful has much to do with her probing study of Adolf Eichmann, the man on trial for his key role in the Holocaust. Although Williams blends in examples from the Holocaust, Armenian Genocide, Cambodian Genocide, Bosnian Genocide, and Rwandan Genocide in his narrative, these examples cannot offer the same gripping analysis that qualitative studies like Christopher Browning’s Ordinary Men or Wendy Lowers’s Hitler’s Furies offer.

Unlike his discussion of motivations, Williams’ analysis of so-called facilitative factors of genocide—factors that “have an impact on the participation decision, although none of them would suffice alone” to cause someone to conduct genocide (127)—uses greater storytelling to bolster his analysis. Here, he brings in poignant interviews he conducted with Cambodian perpetrators and in so doing intertwines the qualitative with the quantitative. These original sources enrich his presentation of the four facilitative factors he introduces: ideological framework, dehumanization, group dynamics, and time. His expertise in the Cambodian case allows him to make original contributions to the scholarship within and beyond the Complexity of Evil model. His analysis of the ideological and moral justifications for genocide under the Khmer Rouge elucidates the extremity of that regime as it relates to the cadres’ acceptance of propaganda targeting well defined categories of enemies like the Vietnamese and Cham Muslims, as well as newer categories of otherness invented by the Khmer Rouge (129-136) not necessarily tied to the 1948 UN definition of genocide.

Context is the third and final consideration of the Complexity of Evil model and in it Williams combs through the “political, economic, and cultural factors that together create an environment that is particularly conducive to genocide” (212). His main point here is that five macro issues—the state, societal tensions and divisions, ideology, instability, economics, and cultural norms—help to explain why certain motivations and facilitative factors become more prominent than others. The importance of this category is further exemplified in the penultimate chapter wherein Williams applies the Complexity of Evil model more conclusively to the Holocaust, Cambodian Genocide, and Rwandan Genocide. Again, it is his analysis of the Cambodian Genocide that again stands out. His scrutiny of the cultural factors that contributed to the Cambodian Genocide indicate a new and expanded focus that earlier studies on the Cambodian Genocide did not address (195).

Ultimately, in this multidisciplinary and comparative study of genocidal violence, Williams excavates what we already know about individual perpetrators to unpack what motivates genocidal action. In this reader’s opinion, the final product may have additional value when used to study other atrocity crimes, namely crimes against humanity, war crimes, and ethnic cleansing. Williams does acknowledge that participation in genocide as opposed to other crimes is unique given that unlike other crimes, genocide requires proof of intent to destroy an ethnic, racial, religious, or national group, but I would argue that for the low-level perpetrators he is studying, intent is not necessarily relevant to all their actions (7-8, 215).

When it comes to prosecuting perpetrators for the crime of genocide, intent is key. It is for this reason that historically those who have been found guilty of the crime of genocide by international criminal courts are not individual foot soldiers and rather the planners and leaders of genocide. However, this study is not about the illegality of genocidal violence and instead about the conditions that support an individual’s actions within a violent system. Nothing in the Complexity of Evil Model, when applied to low level perpetrators or foot soldiers, is exclusive to genocidal systems. Indeed, all the categories and subcategories of analysis he highlights bare value when looking at it as applied to totalitarian, fascists, and extreme communist regimes. We can see this most profoundly in Williams’ analysis of the Cambodian case. The majority of the Khmer Rouge’s victims do not fit within the narrow confines of victim groups as defined by the United Nations Genocide Convent (1948), and yet the processes in which ordinary perpetrators justified their actions was the same whether the victim was a Cham Muslim or alleged political opponent of the Khmer Rouge. This is not indicative of a weakness in this study, rather perhaps an indication that unlike in that past, now it may be worthwhile to decentralize our focus on genocide in favor of looking at regime sponsored violence more holistically, at least as it pertains to the functionaries of violence.


University of San Francisco


Anderson, Kjell. Perpetrating Genocide: A Criminological Account. (New York, NY: Routledge, 2018)

Chalk, Frank and Kurt Jonassoh. The History and Sociology of Genocide: Analyses and Case Studies. (New Haven, CT: Yale University Press, 1990)

Melson, Robert. Revolution and Genocide: On the Origins of the Armenian Genocide and the Holocaust. (Chicago, IL: University of Chicago Press, 1992)

Straus, Scott. Fundamentals of Genocide and Mass Atrocity Prevention. (Washington, DC: The United States Holocaust Memorial Museum, 2016)

Waller, James. Becoming Evil: How Ordinary People Commit Genocide and Mass Killing (New York, NY: Oxford University Press, 2002)