In this ambitious and impressive monograph, Volha Charnysh examines one of the most urgent challenges facing the world today: large-scale forced population movements and their consequences. According to the UN High Commissioner for Refugees, at the end of 2023, there were more than 117 million forcibly displaced people worldwide—a number that had increased in each of the preceding 12 years and has certainly grown further since 2023 (https://www.unhcr.org/global-trends). These figures are enormous, and contemporary political discourse tends to emphasize the manifold problems that forced migrants allegedly impose on the societies that receive them. As Charnysh states, the prevailing wisdom appears to be that “forced migration and resulting heterogeneity are detrimental to the institutional development and economic performance of receiving societies” (p. 21).

Charnysh “urges scholars to rethink both the benefits of ethnic homogeneity and the costs of hosting refugees” (p. 8). She intends to show that “forced migration, a traumatic event, can strengthen states and benefit local economies in the long run by increasing social heterogeneity at the subnational level” (p. 8). Empirically, Charnysh draws on two case studies: Poland and (West Germany), both in the early aftermath of World War II, in which the two countries experienced large-scale forced migrations, and in the decades since, stretching up to the present. She employs a carefully designed mixed-methods approach. Her extensive qualitative evidence comes from historical archives, memoirs, newspapers, and secondary research literature in Polish and German. The quantitative material, in turn, derives from four original datasets that provide detailed information about longer-term developments, particularly economic trends, in a range of localities in both countries.

Charnysh’s key findings can be grouped under three main headings. First, she concludes that in the early post-1945 period, forced population movements caused significant “cultural differentiation in both Poland and West Germany” (p. 19). The “fiction of shared … nationhood” broke down in both countries, as uprooted populations that were supposed to be co-ethnics of the dominant ethno-national group (refugees defined as Poles arriving in postwar Poland and those defined as Germans settling in postwar [West] Germany) struggled amidst economic scarcity and socio-political uncertainty (p. 19). Several cultural markers, including religious and linguistic differences, contributed to the emergence of “new group boundaries, but what ultimately mattered most was opposing economic interests” (p. 19). In the post-war context, then, conflict was rife: arriving forced migrants were frequently viewed as foreigners rather than co-nationals by more established residents of areas that experienced a refugee influx, and a new kind of heterogeneity reigned at the grassroots level.

Charnysh’s second main argument has to do with state capacity. In a challenge to interpretations that view the arrival of forced migrants as a major problem for state authority, she maintains that “dealing with a sudden inflow of migrants shored up the role of the state in the provision of collective goods and increased state capacity in the long run” (p. 19). Uprooted individuals and communities typically turned to the state for assistance, and communal elites, weakened by the upheaval around them, became “more willing to endorse—or less able to resist—state building projects in their communities” (p. 12). Forced displacement therefore created “a window of opportunity for strengthening the state by reducing resistance to revenue extraction and shoring up societal demand for state-provided public goods” (p. 12).

The third—and most far-reaching—argument focuses on the economic consequences of big population displacements. Like many other scholars, she acknowledges that in the short term such events strain resources and impose burdens. Significantly, however, she contends that over the long haul the picture looks different: “one to two generations later … communities that received a larger and more heterogeneous migrant population … economically outperformed communities with a smaller of more homogeneous migrant population” (p. 20). Her primary explanation for this outcome derives from “the diversity bonus” (p. 198): the long-term gains in economic activity and productivity generated by the inter-mingling of people with varied cultural backgrounds and skill sets. Charnysh’s economic argument contains a significant caveat, however; the long-term benefits of “migration-based diversity” prevail “only under inclusive formal institutions” (pp. 20–21), that is in polities such as (West) Germany, in which “the state protected property rights and encouraged private entrepreneurship” (p. 230). In authoritarian political systems, such as Communist-era Poland, similar benefits fail to appear, but even there, they become possible once the institutional setting is transformed. Thus, in the Polish case, the economic advantages enjoyed by regions that had experienced a heavy influx of forced migrants after WWII appeared about a generation later than in (West) Germany—after the collapse of Communist rule and the transition to a market economy.

Charnysh’s monograph is a major achievement that deserves a wide readership among social scientists and contemporary historians. The study is carefully constructed, fluidly presented, and convincingly argued. As a historian, this reviewer was impressed by the insightful use of varied ego documents in both German and Polish on which the author draws in developing her interpretation of grassroots-level developments in the early postwar era. But Charnysh’s primary scholarly contributions lie in broader claims that pose important challenges to the existing literature in comparative politics and related fields. Through her case studies, she shows that, far from undermining the institutional development and economic performance of receiving societies, forced migration and the heterogeneity that it brings can in fact strengthen state institutions and boost economic performance in the longer term. Her findings also cast new light on the relationship between wars and state-building by highlighting ways in which the practical consequences of forced displacement provide opportunities for extending and strengthening state capacities. These are re-interpretations whose impact on future scholarship can be far-reaching.

My criticisms of this fine study are minor. From a historian’s perspective, Charnysh’s claim that social scientists have paid “little attention” to “postwar displacements in Europe” (p. 22), especially on the communal level, seems somewhat overdrawn. If one counts (at least some) historians as social scientists, the amount of available scholarship is considerable. In (western) Germany alone, there are significant local studies by a number of historians, including Rainer Schulze (whom Charnysh cites) or Alexander von Plato and Adam Seipp (who are not included in the bibliography). A broader issue relates to the wider applicability of Charnysh’s theses. She freely admits that her argument about state-society relations in migrant-receiving communities “fits best in cases where the uprooted population enjoys full citizenship rights” (p. 23), which is very rarely the case with today’s refugees. In the concluding chapter, she applies her model to three sizeable groups of twentieth-century forced migrants: people uprooted to Greece from Turkey in 1919–1922 and to India from the border regions with Pakistan in 1947–1951, as well as the French pieds-noirs who fled from independent Algeria in the early 1960s. Her observations are fascinating but also very brief (three pages in total), and further elaboration would have been desirable. Perhaps that can follow in future publications.

Overall, Charnysh has written a significant and highly illuminating study, combining history and political science to great effect. It is to be hoped that her forceful arguments about the long-term positive economic and societal effects of migrations can find a wide hearing at a time when poisonous populist rhetoric against refugees and migrants in general has reached alarming proportions.