What explains the direction and magnitude of immigration policy change in liberal democracies? Despite long-standing aspirations to develop large-scale cross-national comparisons able to produce a grand theory of immigration politics and outputs, the diversity and complexity of migration systems render the task rather difficult. Trade-offs seem inevitable. Much of the existing literature has attempted to elucidate policy dynamics based on a limited set of variables, which can be broadly classified into the clusters of institutions, ideas and interests. In The Comparative Politics of Immigration: Policy Choices in Germany, Canada, Switzerland, and the United States, Antje Ellermann ambitiously builds on these foundations to develop a more comprehensive and comparative theory of immigration policy making in liberal democracies, grounded in solid empirical analysis.

The theoretical framework laid down in the first chapters of the book is impressive both in its scope and sophistication. Ellermann's main argument is twofold, combining institutional factors and policy actors’ strategic behaviour. It purports to explain two dimensions of immigration policy change: the direction of change (toward liberalization or restriction) and the magnitude of the change (incremental or paradigmatic). First, building on an institutionalist perspective, the author argues that the direction of policy change is contingent on political insulation—that is, the extent to which policy arenas (executive, electoral, judicial) are accessible and responsive to domestic and international pressures. More specifically, Ellermann identifies three types of political insulation: popular insulation from citizens’ demands and preferences, interest-group insulation from lobbying efforts by organized interests, and diplomatic insulation from pressure from both receiving states and sending states (19). Ultimately, the argument points to the salience of popular insulation and diplomatic pressure by receiving states to account for policy liberalization, whereas strong insulation from organized interests and sending states explain restrictionism. Second, Ellermann advances three necessary conditions for paradigmatic policy change: loss of congruence between a paradigm and its environment, the presence of broad-based debates and the absence of institutional veto points (81).

Empirical chapters test Ellermann's theoretical argument over two pairs of cases: Switzerland and Germany, identified as guest-worker states; and Canada and the United States, paired as colonial-settler states. Each case is discussed in a separate chapter, with an analytical focus on policy reforms related to family and economic migration from the postwar era to the 2010s. The research design is solid, as it allows the tracing of policy change over time in similar contexts while simultaneously allowing for institutional and ideational variation. In Switzerland, the lack of insulation of policy makers creates a situation of permanent pressure whereby policy makers have to accommodate plural and competing demands. While paradigmatic change is discernable in Germany, the presence of veto points has considerably impeded the adoption of a new paradigm. In Canada, the locus of authority situated in the executive arena and the strong political insulation of policy makers explain why the country has gone through frequent paradigmatic reforms. Finally, the centrality of Congress in immigration policy making and its numerous points of access for interest groups render paradigmatic shifts very unlikely in the United States.

Ellermann presents her argument following a meticulous justification of her theoretical and empirical choices. However, as a central variable for the argument, paradigm shift merits further theoretical attention and empirical development. This is especially relevant at a time when the spillover effect of the neoliberal paradigm over many policy areas is evident and when immigration policy is treated as a “visa mix” (Boucher and Gest, Reference Boucher and Gest2017, cited in Ellerman, 3) constituted of distinct admission policies that can be governed by contradictory paradigmatic logics. As the book mentions, it is likely that “competing paradigms will coexist in a given place and time” (79), although the author argues that one paradigm is generally more salient. How to understand paradigmatic shift in the presence of spillovers and sometimes overlapping paradigms? This theoretical disentanglement could prove useful to explain why the passage of the Canadian Immigration and Refugee Protection Act—identified as a paradigmatic shift—did not trigger broad-based political contestation (239). It might also account for the counterintuitive 2019 Skilled Worker Immigration Act in Germany that Ellermann concedes as a paradigmatic shift (in surface) whose “actual impact . . . is likely to be modest” (190). Finally, given the increasing politicization of immigration issues across countries, we can wonder to what extent differences in political insulation will remain a key characteristic of policy arenas and continue to be a determinant for policy making.

The Comparative Politics of Immigration compellingly uncovers some distinct logics of immigration policy making. Although the work is theoretically dense, Ellermann offers a well-constructed and clear unfolding of the argument. The book is particularly relevant for researchers interested in comparative politics, public policy, and migration studies. Given the remarkable balance achieved between depth and parsimony, it will certainly become an essential work to engage with for migration scholars. For that matter, the conclusion puts forward promising suggestions for the application of the framework to other migration-related policy areas and to the supranational and subnational levels.