International order, as we have known it over recent decades, is in deep trouble. In a world characterized by “the global expansion of authoritarian rule” (Freedom House 2022), including the spread of xenophobic and racist populism in the order’s core and the open commission of atrocity crimes by two of the order’s Great Power Permanent-5, the established norms and institutions that constitute the much-debated liberal international order are under threat as never before. Rapid, almost incomprehensible technological advances, geo-economic shifts resulting in (and from) concurrent processes of globalization and deglobalization, and profound ecological crisis rapidly seem to be bringing in a bewildered age. How to make sense of it? In the midst of this “unmoored, uncertain transition” (p. 282), many scholars have drawn on historical patterns of ordering to better anticipate what might emerge on the other side. Yet Glenda Sluga’s achievement, in this rich and ambitious study of one of the order’s multiple births during the peacemaking process that followed the Napoleonic Wars, is to draw our attention to the fluidity, contingency, and ever-shifting horizons of experience and expectation that condition what (and how) we imagine politics between states to promise or even to be.

When discussing a book, it often helps to get the very obvious out of the way, and so, to anticipate your anticipation, Glenda Sluga has written an excellent book—and one that is not just excellent but also important. By opening the forgotten (or intentionally erased) vistas of this particular point in the construction of the international, Sluga shows how the character, extent, and reach of international politics were (re-)created within the imaginative prism of exclusion (whether of colonized peoples, victims of war, and exploitive capitalist practices; women; non-Europeans; and the “lower social orders” in general) and inclusion (of new or revived actors and forces: national, economic, social, scientific, and even philosophical). Yet, while drawing our attention to the fluidity and the constantly evolving process of contestation and renegotiation that attends to the construction of (any) international order, Sluga—using one of the great strengths of history—reminds us also that this process embeds decisions. For this reason, her account of emerging order does not leave the reader flailing in a hopelessly unnavigable sea of abstract forces.

In Sluga’s hands, the story of the emergence of the international order is woven in between the personal narratives of individuals whose activity reflects the breadth of the possible politics being defined and melded into a revised order. Following the “ideological earthquake” of the French Revolution (p. 3), the Napoleonic Wars disrupted European politics in fundamental ways. Creating new geopolitical realities that could not simply be undone, contemporaries self-consciously understood themselves to be seizing the opportunity to make a wholly new politics. This was an endeavor shot through with philosophical idealism (p. 98). This combination was evidenced most clearly in the nascent multilateralism established in the Treaty of Chaumont in 1814, which committed the allies to continue cooperating after the war ended, inspired by the goal of establishing perpetual peace. Powerful men such as Castlereagh, Alexander I, and, above all, Metternich believed themselves to be “masters of the world,” shaping events in their own image.

Sluga takes great care to reintroduce the alternative forms and forums of politics that were sidelined in the ensuing constructions of modernity and of politics that emphasized professionalization, bureaucracy, and “masculinity.” In particular, the salon culture provided such a potent force that Germaine de Staël, who mastered its form, came to be known to contemporaries as the third great power in Europe along with England and Russia (p. 27); she was one of Bonaparte’s great antagonists. As politics between states eventually came to be ordered in such a way as to exclude women and to privilege a civilizational and racist fiction of European superiority, the structure of which continues to shape international politics today, Sluga’s book reclaims the possible futures foreclosed in the peacemaking that happened between 1814 and 1815.

After all, the international order is an idea constituted by practices that are continually contested, negotiated, and reimagined. In contrast with a tendency to conceive of an order as a coherent and relatively stable meta-institution accounting for the transnational distribution of political authority, Sluga’s history instead encourages a reading of it as interconnected and interwoven practices. By training the eye on this interpretive precondition of ordering processes, Sluga highlights the way in which the international order is a product of thinking about the possibilities of politics between states, of who gets to do politics, and—critically— of how the past and future are imagined. Indeed, the focus of her study, the intense period of postwar peacebuilding at the close of the Napoleonic Wars, sits at the fulcrum of what historian Reinhart Koselleck describes as Sattlezeit in The Practice of Conceptual History: Timing History, Spacing Concepts (2002). Sluga describes “a bridging century… between the ancient and the modern worlds that began around 1750 and lasted a hundred years… (and represented) a new capacity to imagine the future perched on an aspirational horizon of advancing and receding time” (p. 8). In many ways reminiscent of the peculiar historical condition of the early twenty-first century, Sluga’s history of nineteenth-century order building is timely.

As the Napoleonic Wars ground to a halt, according to Sluga, “Europe became the site of shared moral and political (liberal) values and institutions pushing humanity further along the path to social and political progress, liberty and political equality” (p. 79). But this liberal, cosmopolitan moment did not preclude establishing civilizational hierarchies (p. 81), and much less could its nascent multilateralism give rise to the Enlightened perpetual peace those foolish, powerful men felt within their grasp. The paradoxes of violence, exclusion, and exploitation that lived alongside the high-minded ideals of progress, law, and rights plague the contemporary international order as much as they did the post-Napoleonic. This is one of the ways in which Glenda Sluga’s account of how the order was conceived, the ambiguities and the movement, and “the unsettledness, unpredictability, and unevenness of the past” (p. 282) speaks to the present idea of a liberal international order in crisis. Most of all, it reminds us that the scope of the politics between states, of who it includes and who it excludes (consciously or otherwise), is ever up for negotiation. As a “multiplex order” threatens us with its precarities (see Amitav Acharya, “After Liberal Hegemony: The Advent of a Multiplex World Order,” Ethics & International Affairs, 31[3]: 2017), this important history of emergent ordering processes shows that how we define the spaces where politics is done and allocate access to participation in shaping a vision of what politics means is crucial.

With these challenges in mind, Sluga’s work provokes several questions. In these debates over the future of the international order, IR scholars are as inclined to look backward as forward. Although some have hypothesized the reemergence of Cold War bipolarity, with China facing off against the United States in a generalized macro-security competition, others foresee the return of a balance-of-power, multipolar order akin to the nineteenth-century European states system. The particular contribution that historical accounts can make to these debates, especially broad and deep histories such as the one produced by Sluga, is to color in the caricatures, to fill out the shorthand images of the past that IR scholarship so often leans on in reaching for such analogies.

Because as Sluga has underlined, order building—especially when it occurs at significant critical junctures such as peace conferences that conclude major wars—is not a lineal process. It inevitably involves redefining the boundaries, limits, and terms of what “politics” becomes international. We find the same basic question being asked whenever we encounter these seminal moments of order building in European and global history, whether in Osnabrück and Münster, Vienna, Berlin, Paris, or San Francisco: What aspects of politics are to be subject to common rules, and what issues are taken to reflect the common concerns of international society?

One possible explanation for the contemporary crisis in the international order is that it has outlived the previous institutional consensus on these questions. Current arrangements have been overwhelmed by the number of challenges that can no longer be contained by domestic politics but that are not yet fully embraced by the “international.” The legitimacy gap brought about by this conflict, then, demands a fundamental reordering. If we are indeed facing a reckoning of this kind, what does Sluga’s history tell us about how the process of exclusion happens? How do narrow interests reassert themselves, time and time again? Acknowledging this (in the context of San Francisco and Paris as much as Vienna), when confronted with moments of possibility, what strategies—political, rhetorical, and institutional—can be used to evade the pitfalls of a narrower politics that we so often fall into? Sluga shows perfectly well that it is not enough simply to have participation—voices around a table. Perhaps we need to reconceptualize the very terms of the debate or to interrogate the path dependencies on which our existing concepts lead us. What do we really mean by “universal” or by sovereignty, peace or self-determination? None of this is to charge Sluga with the indomitable task of prescribing new methods of order building; it is rather the historians’ privilege to ask questions. But the richness of her study and the mournfully teasing “what could have been” leave the reader inevitably thinking about how political and economic interests can be brought in line with wider conceptions of politics and notions of peace.