While cosmopolitans have long dreamt of a world republic where ‘there’s no countries’, to quote John Lennon, Kant himself preferred the federation of nations without coercion over such a world republic. Some interpreters, whom Luigi Caranti refers to as ‘moderate cosmopolitans’ (Habermas Reference Habermas1998; Habermas Reference Habermas2006; Höffe Reference Höffe and Höffe2004, Reference Höffe2006; Kleingeld Reference Kleingeld and Caranti2006; Kleingeld Reference Kleingeld2011; Pogge Reference Pogge and Caranti2006), nonetheless have attempted to claim that we can still defend the ‘minimal world republic’ (p. 51) on Kantian grounds by loosening the tension between the idealist interest in dissolving states into a world republic and the realist concern for the preservation of a plurality of states. Against this attractive reading, Caranti’s illuminating new book aims to defend Kant against such an idealist reading by seeking out the condition under which a world republic can sustain itself in this actual world.

Caranti’s aim in this book is to show that Kant provides plausible evidence to prefer the federation over the world republic as well as that, on Kantian grounds, the only condition under which we can conceive of realising the world republic in this actual world is that all citizens (not a majority) consent to dissolving states. According to Caranti, Kant preferred the federation because Kant thinks that it can best preserve the freedom of citizens, whereas the world republic could undermine this because of its possible erosion of states’ sovereignty. At the same time, however, Caranti is well aware that Kant never abandoned the possibility that states might voluntarily choose to dissolve themselves in order to enter a larger global institution (pp. 44, 51).

Caranti’s valuable contribution is thus drawing our attention to Kant’s actual concern for the freedom of citizens and to why this concern leads to his preference for the federation over the world republic. Moreover, Caranti’s contribution is not merely exegetical, as it provides us with important insights into our actual need for the Kantian federation and what it might mean to conceive of a world republic today. Caranti’s primary example of the Kantian federation is the EU because, according to Caranti’s understanding (prompted by Pogge), it mirrors the tension between the process of furthering integration while remaining a confederation of sovereign states, a tension that Kant tackled in all of his political writings (p. 59). In what follows, I first outline the structure of the book and then offer my take on a controversial issue that surfaces throughout Caranti’s account of the Kantian federation, namely the elusive place of morality in political philosophy.

After Section 1, which serves as the introduction to the book, Section 2 delineates Kant’s theory of peace as presented in Towards Perpetual Peace with a detailed exposition of the six preliminary articles, which ensure that factors generating hostility among states are removed, followed by articulating three definitive articles: ‘the civil constitution in every state shall be republican’ (TPP 8: 349); ‘the right of nations shall be based on a federalism of free states’ (TPP 8: 354); and ‘cosmopolitan right shall be limited to conditions of universal hospitality’ (TPP 8: 358). This section, which ranges over 20 of the 66 pages of the entire book, not only serves as a first-rate account of Kant’s project of perpetual peace but also is suitable as an introduction to Kant’s theory of peace for Kantians and non-Kantians alike, including policy makers.

Next, Section 3 situates Kant’s project of perpetual peace in the context of his critical philosophy. Section 4 then traces the evolution of Kant’s thought on international right. According to Caranti, although Kant’s view has been geared towards preferring a federation over a world republic over time, the underlying thought that a world republic is the only guarantee of peace has not changed (pp. 9, 39, 42). Section 5 discusses Kant’s three arguments – empirical, logical, and moral – for his preference for the federation of nations (Völkerbund), which is characterised by non-coercivity, over the state of nations (Völkerstaat), where some unifying principles coerce nations. Caranti argues that Kant’s moral argument is the strongest among these, based on Caranti’s emphasis on the freedom of citizens which the ‘moral personality’ of states rests on. Section 6 deals with the common ‘federation versus world republic’ picture by presenting the readings that moderate cosmopolitans endorse. In response to these readings, Section 7 suggests the problem of moderate cosmopolitanism. This section includes consideration of the history of real politics from the late twentieth century to the present, thereby serving as an entry point for non-Kantians and policy makers to cultivate their interest in the topic of the Kantian federation. Section 8 focuses on what Katrin Flikschuh (Flikschuh Reference Flikschuh2010) terms a ‘sovereignty dilemma’, where Kant’s theory of right, although it is analytically connected to coercion, simultaneously requires coercion within states and prohibits coercion imposed by other states. Caranti argues that this is not a dilemma but indeed what he calls the ‘antinomy of practical-political reason’, which rather vindicates reason’s power and extension. Section 9 concludes the book by spelling out, on Kantian grounds, Caranti’s own reasons for preferring the federation over the world republic. After all, Caranti is sceptical about the possibility that all citizens agree to dissolve states at the risk of undermining the freedom of each individual, which, as Caranti so argues, those individuals exercise only under states’ sovereignty.

Caranti demonstrates his extensive familiarity with the literature, and there is no doubt that this book is a significant contribution not only to Kant scholarship but also to political philosophy more broadly, especially to debates over federalism and cosmopolitanism. However, I would like to comment on two issues from the perspective of a moral philosopher interested in the place of morality in political philosophy, in order to highlight some desiderata that we need to fulfil in our future endeavours within Kant scholarship and beyond.

First, it is not obvious to me what Caranti means by ‘the moral personality of the states’ (pp. 3, 42, 51, 55), a topic that has its own tradition both within and outside of Kant scholarship (cf. Byrd Reference Byrd, Sharon and Hruschka2006; Walzer Reference Walzer and Beitz1985). Although Caranti speaks of the ‘division between virtuous and nonvirtuous states’ (p. 20), he maintains that Kant rejected this division. But if states cannot be described as virtuous or nonvirtuous, that is, if we cannot personify states, how can one say that ‘they already have a moral personality’ (p. 42)? Moreover, before this statement Caranti claims that ‘states may not need to be forced to abandon the state of nature’ (emphasis mine). To be sure, as Caranti rightly mentions, states exist in the state of nature in international relations for Kant (pp. 4, 18; see MM 6: 246, TPP 8: 357). But is such a moral personality of states retained after they leave the state of nature and enter the civil condition (see MM 6: 306–7)? I would like Caranti to have solved the confusion: he claims that states already have a moral personality in the state of nature; yet, it seems to me that states change their moral personality by entering the civil condition. If, as both Caranti and moderate cosmopolitans believe, preserving states’ sovereignty is an important issue, I would like Caranti to have clarified what kind of sovereignty is at stake and in what sense it has a moral personality. Is Caranti concerned with preserving that sovereignty of states which already exists in the state of nature, or is he rather interested in changing a moral personality of the sovereignty of states in accordance with the transition from the state of nature to the civil condition, as indicated in his interest in the move from the ‘domestic’ state of nature to the ‘international’ civil condition (pp. 36, 40, 42, 46, 55)?

Second, I would like Caranti to have developed what he mentions as ‘the complexity of human affairs’ (p. 3). To be sure, Caranti helps demystify the teleological nature of human affairs, namely the mystery about Kant’s thesis that nature somehow guarantees that humanity will one day reach perpetual peace (pp. 26–31). But Caranti does not explain in what way this teleological nature of human affairs is complex and how those affairs unfold in the actual political sphere. Even more, Caranti does not scrutinise such ethically charged concepts as mutual trust and respect (p. 20) and conscience as it occurs in various expressions – as in ‘a common conscience’, ‘a common moral conscience’, and ‘global moral conscience’ (pp. 25–26) – and clarify how these concepts help us better understand Kant’s political philosophy. I would have liked Caranti to make clear what he has in mind when he mentions mutual trust and respect, for example, by illuminating whether they are trust and respect among individual persons or among states. In a similar vein, I would have liked him to explain what he means when he says that conscience is global. Is he conceiving of something like one single universal conscience shared by different individuals and states? One can only speculate as to what Caranti has in mind here.

Caranti does show some interest in understanding the place of morality in political philosophy, as this book includes a detailed explication of Kant’s distinctions among the moral politician, the political moralist, the moralising politician, and the despotising moralist (pp. 31–35). Nonetheless, it is our task, if a demanding one, to continue to shed light on the place of morality in political philosophy, because it might be a key to understanding why Kant came to prefer the federation with its emphasis on non-coercion. For non-coercion, it has traditionally been considered the hallmark of morality as opposed to that of politics (e.g. Willaschek Reference Willaschek2009). That said, even without fulfilling these two desiderata, Caranti provides a first-rate account of Kant’s political philosophy.