Studies in religion and politics have already challenged, if not debunked, long-standing myths concerning the relevance and impact of neat book-end dates or concepts such as the peace of Westphalia and the “Westpahlian Order,” in other words the transition from a religious to a secular order. The study of political theology, on the other hand, often lacks the traction necessary to make a sustainable impact on International Relations. One reason for the niche existence of political theology is that it only intermittently links with the broader field of religion and politics. This is surprising, as one would assume that a focus on theology requires such a broad focus.

Fortunately, William Bain’s Political Theology of International Order is one of those rare studies that builds this conceptual bridge, and as such it has the potential to affect how we think about the relevance of theology for studying international relations. It does so by offering an interpretation of international order through the lens of nominalist medieval theology. Seen this way and contrary to conventional wisdom, “religion” is not just another variable to explain the world. Rather, theological “ideas structure the underlying character of international order” (p. 54). Regardless of what approach to international relations one takes, the common understanding underpinning all impersonal mechanisms or rules, is that they all can be “comprehended as objects of knowledge by observing behaviour.” Bain argues that this approach is “in fact, a worldly application of a theological pattern” (p. 2.).

Bain sets out to illustrate the flaws of the narrative of the secular arrangement of the modern states system as one supposedly succeeding medieval institutions. This transition, the mainstream International Relations narrative goes, got rid of the language of religion, while at the same time claiming to explain the state system’s observable behaviour. It is the merit of Bain’s work, and a slowly growing body of literature, to show that this behaviour is dependent on certain presuppositions, comprehensible only by having a close look at theology. Relying on R.G. Collingwood (Essay on Metaphysics, 1940), Bain contends that “logical efficacy, rather than truth, is the test of an absolute presupposition that can only be assumed for the purpose of argument” (p. 17). The very idea of order, then, entails a logic of theology.

Certainly, applying theological vocabulary and concepts for explanations of the modern states system is nothing new. Carl Schmitt’s work (e.g., Political Theology, 1922) or Leo Strauss’s analogies go a long way towards explaining the omnipotence of God, the state, and its behaviour. Take, for example, decisionist policies and the politics of sovereignty and their capacity to transgress the established legal order as well-known examples of this phenomenon. Yet the context of these analogies has been interpreted as one of supplanting or replacing religion and its theological interpretation. Political Theology of International Order argues, however, that beyond this context (i.e., the transformation from a religious to a secular order), it is worthwhile to direct our attention “to the logical efficacy of ideas and their attendant assumptions, propositions, and statements” (p. 52). In doing so, it becomes clear that the “capacity for extraordinary action in politics must be interpreted against the backdrop of God’s self-imposed promise to uphold the order he freely chose to establish” (p. 225).

The theological roots of international order thus persist in several ways. For example, in international relations parlance, these theological debates shaped the question of “whether the international order is a contrived arrangement, born of will and artifice, or a natural arrangement that arises without intention or design” (p. 22). Neorealism, for example, assumes the balance of power as a self-regulating pattern or, alternatively, that this behaviour is the result of free human agency. Bain illuminatingly argues that beyond describing theological analogies, God, “conceived as either a rational being or a willful person, is the absolute presupposition that grounds rival theories of order” (p. 18).

The first part of the book illustrates these two kinds of rival conceptions of order: immanent and imposed, tracing both back to medieval theology. Part two illustrates how these concepts became fixed during the Renaissance, Reformation, and all the way to Westphalia and beyond. Doing so, Bain provides a fresh re-interpretation of the presuppositions from thinkers of (international) order from Martin Luther, to Hugo Grotius, to Thomas Hobbes. The third part of the book describes the entire modern international order as based upon medieval theology. For International Relations theorists this part most clearly illustrates that more is at stake than just context and identifying theological language and analogies.

For Bain, International Relations’ very own dogma explaining the international order as one underneath “an empty sky from which the gods have departed” (Hans Morgenthau, Politics Among Nations [1948]) therefore conceals that “the deification of man deviates from the theological original, exposing the regularity of international order to the whims of arbitrary power” (pp. 224-225). In other words, remove God from this system of presuppositions, and the “corresponding pattern of thought collapses into confusion” (p. 18). Bain illustrates how the theory of imposed order, the dominant discourse in international relations scholarship, developed out of nominalist theology. This discourse persisted well through the development of the modern states system and its consequential contractual international order relying on such presuppositions. Today, it continues in secular alternatives to God that are nevertheless still sustained through faith in secular postulates. Today’s concepts such as common humanity or rational autonomy, for example, provide “no more security than professing faith in God” (p. 213).

Religious dogmas and presuppositions, interpreted and narrated through theology, are thus what we all invariably rely on in some form when thinking about and tinkering with the world of politics. Political theologians have previously sought to illustrate the relationship between the religious and the secular realms. Yet Political Theology of International Order goes beyond these earlier studies and also clarifies some of their epistemological shortcomings. As Robert Wuthnow (“Understanding Religion and Politics,” Daedalus, 120[3], 1991) points out, good theory is not foremost about prediction. Good theory helps us think about the significance of processes and events.

Empiricists and (nominal) secularist International Relations theorists might want to see more regarding the empirical ramifications of Bain’s argument. Given the detailed theoretical outline of the book, some might seek, for example, a discussion of the tangible institutional or policy outcomes of the theological roots of international order. However, it is the merit of Bain’s work to lay the groundwork for just that sort of application of its theoretical engagement in future studies. Yet even more than that, Political Theology of International Order challenges the common mentalité of the nominal secular rationalist cast of mind that Michael Oakeshott—an important influence on Bain’s book—lamented long ago in Rationalism in Politics (1962).