Daniel Karch examines the German colonial campaign against the indigenous peoples of German Southwest Africa (present-day Namibia) at the beginning of the twentieth century and the expansion of US federal power into the northern Great Plains against the Sioux nation in the latter half of the nineteenth century as manifestations of “colonial and imperial power projection” (29) both of which served as nation-building projects and expressions of contemporary population policies.

Karch's study intersects with two current areas of historiographical focus. First, this work is one of several recent monographs within the field of genocide studies that examine cases of mass killing or genocide employing a comparative and transnational framework. Second, the work engages with recent scholarship dealing with the process of settler colonialism and the role of the United States as an imperial power based on the conquest and subjugation of indigenous populations in the American West in the nineteenth century. As the title implies, Karch's major contribution to this discourse centers on his introduction of the concept of “unrestrained violence” as a scaffold for evaluating the process by which colonial powers attempted to assert control over indigenous peoples, an approach heavily influenced by the scholarship of Birthe Kundrus, and one that is evocative of Christian Gerlach's Extremely Violent Societies: Mass Violence in the Twentieth-Century World (2010). Furthermore, he directly engages with broader debates related to the use of the term genocide as a construct for defining cases of imperial conquest.

An edited and slightly shortened version of Karch's dissertation, the work reflects the virtues and the necessary vices of the genre. Organized into only four chapters, the first chapter discusses theory, terminology, definitions, and methodology, and provides the obligatory detailed source review. Chapter 2 traces the development of international law related to the conduct of warfare, including the passage in 1948 of United Nations Resolution 260, the “Convention on the Prevention and Punishment of the Crime of Genocide,” and reviews the academic discourse and ongoing debates concerning the concept of genocide within the scholarly community. Chapter 3 focuses on the presentation of the two case studies, each considered separately. The last chapter constitutes the work's analytical and theoretical primary emphasis. In this chapter, Karch engages with issues of popular and mythic national narratives and historiographical traditions related to each case. He then evaluates the use of state-sanctioned violence within the two colonial settings using a “structural analysis” that incorporates “sociological and social-psychological paradigms” (32) of perpetrator motivation. Finally, he offers a determination on the appropriateness of employing the term genocide to describe either case.

One of the strengths of the book involves the breadth and depth of the archival sources examined, a task complicated by the transnational focus of the study. Based on the broad availability of primary sources for the US case compared to the loss and destruction of German colonial archival collections, largely as a result of the two world wars, Karch notes, “The quantitative and also qualitative differences in the source base could hardly be greater” (43). Paradoxically, Karch's impressive coverage of US archival sources is not matched by an equally adept coverage of printed sources, whether those related to ethnographic studies on the experience of Native American communities (including those of the Great Plains) or relevant English-language secondary sources in the field. With regard to the latter, Karch may be excused in part for not including some secondary sources, as the bibliography reflects the dissertation submission date of the winter semester 2016–2017. Nevertheless, one might expect that Karch would have included references to Jeffrey Ostler's The Plains Sioux and U.S. Colonialism from Lewis and Clark to Wounded Knee (2004), Carroll “Pete” Kakel's The American West and the Nazi East (2011), and Gary Anderson's Ethnic Cleansing and the Indian (2015). In contrast, the author does an excellent job of including the German-language historiography related to both cases.

Using this evidence, Karch offers a concise yet nuanced overview and analysis of Imperial Germany's colonial campaign in German Southwest Africa between 1904 and 1907, as well as the role of the US federal government and the US military in the conquest of the American West between 1854 and 1877, in order to frame the structural and situational factors that shaped each of these national projects. Ultimately, the work is less about the comparison of the two cases and more about identifying the elements of each that promoted the use of “unrestrained violence” by Imperial German and US military forces on the colonial periphery. The author contends, “Moreover, it is necessary to identify the exact circumstances [of a given case] under which the unrestrained use of violence was possible, allowing ordinary people to become excess perpetrators [Exzesstäter]” (291).

The focus on the specific and unique empirical elements of each case using social-psychological theory results in several findings. First, Karch engages with the concept of a German military Sonderweg as expressed in the work of Isabel Hull and Jürgen Zimmerer, but eventually rejects a trajectory linking Imperial military traditions with those of the Third Reich. Second, he argues that the number of variables and factors associated with individual colonial enterprises renders an overarching concept such as “Colonial Genocide” as “tautological at best” (293). Although he rejects the use of the term genocide to describe either of the cases based on the absence of intent and the absence of “a clearly defined plan” (321), Karch still maintains that the concept of “genocidal violence” should not be discarded, but rather understood as one “possible category of unrestrained violence” (328).

Karch's ambitious study and his concept of “unrestrained violence” offers one alternative for reframing discussions on state use of force against indigenous peoples that allows for a nuanced analysis of these processes and their results, in a way that complicates and enhances our understanding of genocidal violence. Although a number of scholars in the field of genocide studies might disagree with his conclusions, Karch's analysis is deserving of a broad readership within the field.