John Rawls called most of what he did “ideal theory.” The label aptly describes the political theory mainstream. Mainstream egalitarian liberal theory, building on Rawls’ work (or that of Ronald Dworkin), and the more rationalistic forms of deliberative democratic theory have in common an essentially Platonic method. They defend as morally best that imagined republic most capable, in the theorist’s view, of defending itself against the right kinds of rational arguments (whether made in the theorist’s own voice or attributed to equal citizens).

In the past decade, starting with the publication of Bernard Williams’ In the Beginning Was the Deed (2005) and Raymond Geuss’ Outside Ethics (2005), the self-styled realist movement in political theory has taken a very different approach. Avowed or retrospectively baptized realists, including Richard Bellamy, Bonnie Honig, Alison McQueen, Karuna Mantena, Chantal Mouffe, Glen Newey, Enzo Rossi, Rahul Sagar, Judith Shklar, Marc Stears, Frederick Whelan, and this reviewer; and on some accounts John Dunn, William Galston, Geoffrey Hawthorn, David Owen, Mark Philp, and even Michael Walzer draw inspiration from a canon centered on Thucydides, Machiavelli, Hobbes, and Hume rather than Plato, Rousseau, Kant, and Hegel. They portray politics as having its own distinctive rules of action; some, though not all, call those rules a special kind of ethics. Denying the possibility of basing politics on a rational or moral consensus, even a consensus on how to deal with disagreement, they take politics to be everywhere and essentially a matter of conflict—rational, irrational, or both—over the most fundamental questions.

These stances distinguish realism sharply from the idealist mainstream. But realists also differ among themselves. One dimension of disagreement is ideological, reflecting the difference between the two founding authors, Geuss and Williams. Radicals, closer to Geuss, follow a neo-Marxist tradition in rejecting liberal rationalism on the grounds that it mystifies or obscures social and state power. More liberal realists, closer to Williams, strongly reaffirm the institutions and values of liberal politics—constitutionalism, the rule of law, individual choice, civil rights, protections for minorities, a willingness to balance equality against diversity—but fault ideal-theory liberals for understating the permanence and importance of conflict over fundamentals.

This book forces us to acknowledge a second, cross-cutting division—call it “dry” versus “wet”—regarding how thoroughly one rejects the demand for rational justification. Wet realists long for a society that could justify itself with thoroughly good reasons, or could mostly do so, while stressing that such a project must grapple with more conflict, and will be realized less perfectly, than ideal liberals admit. (Even politically radical realism can be wet, on the model of critical theory: it can wield the demand for rational justification—though not an expectation of ultimate consensus—against the inequalities and dominations of the status quo.) Dry realists reject the idea of rational justification altogether, or think it largely beside the point. They think that all institutions and practices rest not primarily on reasons and justifications but on power, sub-rational passions and sentiments, irreducibly partial viewpoints, or social norms and habits. And they see many, perhaps most, political and moral arguments as post-hoc rationalizations for individual or group interests.

In Liberal Realism Matt Sleat, one of the realist movement’s most prominent members, stakes a distinctive and powerful claim to one of these boxes. Liberal Realism is ideologically liberal (though not particularly Left) and distinctly wet. Despite its subtitle, it is less a realist theory of liberal politics than a realist amendment to liberal accounts of justification. Like Williams, whose work he discusses extensively and dissents from judiciously in this book and elsewhere, Sleat believes that political orders must be justified to those who live under them—that their legitimacy depends on their ability to do so. Sleat departs from ideal-theory liberalism in questioning the latter’s aspirations to universality and its implicit teleology. He doubts that any set of public values can accommodate all citizens’ private convictions, and doubts the common, quasi-Hegelian assumption that attachment to liberal values can only expand as opportunities for rational argument increase. Sometimes and in some places, liberal values will not appeal at all; never and nowhere will they appeal to all who might politically matter. Liberalism can therefore, at best, be justified to most people some of the time. Even in those times, it will have enemies who must be coerced because they cannot be convinced. Compared to myths of a liberal consensus, uniquely justified by philosophical theory and ever more stable as a matter of everyday practice, this stress on conflict and coercion is bracingly realist—but within limits. Sleat’s form of liberal realism does not contest the normative demand for justification, nor the implicit premise—often assumed but rarely defended—that a polity’s strength tracks its ability to muster compelling arguments.

Sleat describes the political problem as one of ensuring “stability and order” amidst “radical disagreement, discord and disharmony” (p. 2). “[T]he political question” (Sleat’s emphasis) is “how we are to live together in the face of such deep and persistent disagreement,” how a “common political authority” can govern in its wake (p. 47). His answer, distinctively realist, stresses the “indispensible role of power and coercion to create and maintain stability where none naturally exists” (p. 13). So far, so agnostic on both the above dimensions.

In addition to being a realist, however, Sleat believes in liberalism—and liberalism of a particular kind, defined not primarily in terms of institutions or practices (rights, liberties, constitutions) but in terms of an aspiration to a society whose members live under “principles that…represent their own will” (p. 22; compare 154). Sleat does more than reject, as liberals surely must, a politics based merely on might or domination (p. 48). He also rejects—rather quickly, calling it a “mistake”—Weber’s identification of “the legitimacy of a regime with people’s belief in its legitimacy.” What matters on the contrary is that the political framework “can be justified with reference to the beliefs of a substantial proportion of those over whom it applies” (p. 51; emphasis added). Sleat’s realism appears in that phrase: “a substantial proportion of.…” An ideal-theoretical or rationalist liberal would typically say that the framework must in principle be capable of being justified to all citizens (in accord with Jeremy Waldron’s famous “Theoretical Foundations of Liberalism,” The Philosophical Quarterly 37, No. 147 [1987], 127–50). But a dry liberal would reject the standard of rational justification altogether, without necessarily endorsing Weber’s view that legitimacy is only a sociological category.

Sleat’s wet form of liberal realism leads him to put forth what amounts to piecewise rationalism. On his view, liberal societies can and must prove themselves capable of justification through arguments, but the arguments in question will never appeal to all. The remainder, permanent enemies of the liberal order, must be coerced. The tragedy of politics derives from this need to coerce some members of the polity towards ends they will not endorse (p. 63); more bluntly, some dissenters from liberalism will see the political order as “the imposition of a will other than their own” (p. 127). Sleat, quietly but acidly, accuses standard or ideal liberals of evading the issue through ignoring non-liberals’ wills and attributing to them “the will of liberals” (p. 75). But then how can politics avoid being based on mere might?

Drawing a sharp and useful distinction between “disagreements” within a framework whose legitimacy is acknowledged and “conflicts” over what constitutes such a framework, Sleat affirms the realist position that the latter, true conflicts, are permanent. In broad agreement with most realists, he defines politics as “the sphere of contest between human wills competing for power or influence to determine what decision is taken” (p. 57); again like most, he rejects any suggestion that politics so defined lies outside normative standards and judgments. Sleat departs from many realists, however, in largely retaining the ideal-liberal belief that such standards and judgments must derive from rational justification.

Sleat’s version of liberal justificationism is, to be sure, tragic and chastened. An avowedly “fighting creed” (p. 139), it acknowledges more debts to Niebuhr and Morgenthau than to Kant. Endorsing, and fleshing out, Stephen Macedo’s defense of liberalism’s “moderate hegemony,” Sleat believes that something like standard, justificationist liberalism is both morally required and far more partisan than its proponents typically believe. Its partisan quality is revealed in two ways. First, liberal justification is relative. If I understand Sleat’s argument: While it is always and everywhere the case that legitimate authority must be justified to as many citizens as possible, what citizens will acknowledge as justifiable will vary across time and place. The principle of justification rules out neither socialist (including communist?) nor fascist states: It is simply and, it seems, somewhat accidentally the case that fewer people find fascist justifications persuasive than used to (p. 155–56). Second, no regime embodies the will of all or reflects the values and projects of all. Sleat endorses Mouffe’s tripartite distinction (improving on Schmitt) between friends, adversaries, and enemies. But unlike Mouffe, who would restrict the “enemy” label to those who reject the basic rules of the democratic game, Sleat thinks liberalism must regard as enemies even those who participate in democratic politics but endorse “non-liberal forms of political order” (pp. 147–8), and admits the uncomfortable conclusion that liberals have more enemies than mere democrats do.

Liberalism’s redeeming virtue—its claim to normative superiority over non-liberal alternatives (though Sleat mostly avoids such language)—lies precisely in its way of dealing with enemies. Its moral claims are, one might say, not substantive but adverbial. Liberalism cannot claim a unique ability to justify itself, nor the ability to govern without coercion. Liberal government, like all government, means “ruling” over some who reject the governors’ right to rule (p. 174). But liberals, unlike fascists, are “restrained masters” (p. 152, 161). Believing in universal freedom and equality—even if some of their illiberal subjects don’t—liberals care about the fate of illiberal minorities. Good liberals are tolerant and decent; they refuse to employ certain means even against many who would use such means against them. Friends and enemies are to be treated equally under the law, all being considered innocent until proven guilty (p. 168). Passive enemies who acquiesce in spite of their principles are to be left alone. Only “active,” militant, antiliberal enemies are to be targeted, and there are serious limits to the means that the authorities may use against even them (p. 161). The distinctive liberal virtue is therefore a kind of self-restraint that Sleat explicitly labels a kind of moral character (pp. 161, 168). Liberals, that is, extend freedom and equality to the non-liberal minority not by offering them arguments they can accept—that’s impossible—but by ruling them with decency.

Relentlessly intelligent, innovative, and insightful, this book contains many more clever and persuasive arguments than can be described here. (In particular, one might note Sleat’s fascinating rebuttal of modus vivendi accounts of liberalism, and his creative reading of realist IR theorists, whose relationship to political-theory realism is controverted.) But precisely because no one is likely to do better than Sleat at adapting the liberalism of justification to meet the realist challenge, one might question whether any such adaptation can fully succeed.

The problem with Sleat’s piecewise account of justification is that much of the attractiveness of demanding justification derives from the pieces that Sleat has cut off. The requirement that political frameworks be justified to all those subject to them is commonly defended as uniquely inclusive and critical: It is supposed to smoke out regimes that only appeal to the dominant group, and to open up the public sphere to those who lack social and economic power. To admit that justification is fundamentally partisan—that those who govern according to liberal principles can pride themselves only on having arguments sufficient to convince the substantial proportion of society that happens to uphold liberal principles—is to make the demand for justification more realistic while sapping much of its moral point. And if liberalism’s moral superiority consists primarily of its uniformly decent treatment of friends, adversaries, and enemies, the alleged moral advantages of the justification requirement seem even more beside the point. For the decency in question is a simple matter of how we treat people, not of which arguments we propose to them. The limits of justification are so great as to suggest the advantages of a different kind of liberalism that claims to excel at promoting most everyone’s interests and expanding the scope of most everyone’s choices—not at addressing most everyone’s reason. Such a “dry,” interest-based argument for liberalism might prove both more universal and more critical than one that can only claim to persuade most people, for now and around here.