Persecution & Toleration by Noel Johnson and Mark Koyama adds to the growing list of monographs arguing that religion played an important role in the rise of the Western World. In particular, the book seeks to examine where our modern understanding of religious freedom comes from by describing the interplay between religious legitimacy and state capacity over the long run. It starts from the premise that religion is an inexpensive way of providing social order (p. 295), which explains the widespread reliance of political elites on religion throughout much of human history. A reliance on identity rules, or the treatment of individuals based on social identity, characterized this pre-modern equilibrium, resulting in what they call the conditional tolerance of religious minorities. The book lucidly highlights the costs of this framework which, among other things, restricted movement in ideas, people and goods (e.g., p. 229).

The book then charts how the process of state formation in much of Western Europe undermined religion-based identity rules. As state capacity increased the spread of impersonal institutions drove the separation of religion and politics (p. 300), a decrease in persecution based on religious beliefs (p. 184), and the emergence of religious freedom as we understand it today.

This narrative provides a novel explanation for the rise and the decline of the persecuting state in European history. Its rise was related to increases in state capacity in the identity rules world (p. 69), whereas this same process of state formation eventually led to the collapse of identity rules and the rise of the “tolerating state.” By focusing on institutions instead of ideology (p. 304), Johnson and Koyama uncover important patterns in the relationship between religion and European state formation.

Ultimately, however, their analysis begs the question: Why was the process of European state formation so unique? A host of possible explanations are explored, although the authors stress the importance of the Reformation (p. 197). The Reformation is thought to have made religious legitimacy less politically advantageous by rendering religious coercion impossible, forcing states to transition to more impersonal arrangements (pp. 123, 146).

Yet history is full of ideological shocks that did not result in the emergence of impersonal institutions. Examples include the rise of Christianity in the Eastern Roman Empire or the early Islamic Empires. For centuries these political entities presided over religiously diverse populations they could not immediately coerce. Yet neither witnessed a transition to impersonal institutions or the tolerating state.

While the Reformation may have been a catalyst for the process Johnson and Koyama document, the environment the Reformation interacted with seems the fundamental cause of Europe’s unique institutional trajectory. Johnson and Koyama allow for this possibility when they suggest important interactions with economic developments and the spread of the printing press (pp. 146–47).

This observation resonates with centuries of scholarship stressing the economic and political importance of Europe’s medieval institutions. In recent years, studies have stressed the importance of a host of factors, including the emergence of the nuclear family, proto-representative institutions, and impersonal contracting institutions. Importantly, this line of scholarship argues that by the late medieval period much of Europe was abnormally open to institutional and technological innovation (e.g., Van Zanden, Jan Luiten. The Long Road to the Industrial Revolution: The European Economy in a Global Perspective, 1000–1800, Vol. 1. Leiden, the Netherlands: Brill, 2009).

This alternative interpretation views religious liberty as the product of a chain of institutional changes rooted in a unique political environment. It is thus consistent with Johnson and Koyama’s focus on institutional shifts rather than ideas. Yet it suggests a more gradual decline in the importance of identity rules than Johnson and Koyama’s allow (p. 245). This gradual decline becomes apparent when one expands the focus on religious liberty to include other historically oppressed groups including serfs, women, homosexuals, or ethnic minorities. Such examples demonstrate the emergence of impersonal rules both before and after the time window stressed by Johnson and Koyama depending on which group one focuses on. They also suggest that the spread of impersonal institutions was often rooted in the political empowerment of groups who had an interest in advancing such an agenda. In other words, the advent of modern religious freedom represents one facet of a broader trend towards impersonal rules.

Take seventeenth century Amsterdam as an example. Although it is possible to construe Amsterdam’s tolerant environment as a product of the city’s unique levels of religious legitimacy and state capacity, it is more precise to state that the tolerance of minorities was rooted in the political influence of Amsterdam’s merchant class (p. 187). Scholars trace this influence back to the interaction between the region’s relatively benign medieval political environment and the rise of the Atlantic trade. In this case impersonal institutions for Dutch Christians interacted with a shock (Atlantic trade) to strengthen mercantile elites. These newly empowered elites had incentives to expand impersonal institutions to include religious minorities with trading links to the Americas.

This example illustrates how Johnson and Koyama’s reliance on religious legitimacy and state capacity can lead them to abstract from the political winners and losers in the process of institutional change they describe. This abstraction is often costly, limiting their ability to clearly illustrate how the political forces that drove increases in state capacity led to the demise of identity rules. In other words, changes in quantities such as state capacity or religious legitimacy are ultimately driven by individuals and groups with economic interests. Abstracting from the constraints faced by decision makers restricts both the internal clarity and the external validity (p. 262) of the analysis.

Nevertheless, Johnson and Koyama make a strong case that the emergence of religious liberty was rooted in the process of European state formation rather than in ideology. More broadly, their argument implies that the emergence of the tolerating state and modern economic growth stem from the same political process. These political origins suggest the tolerating state is likely to remain a work in progress for the foreseeable future.