"The Great Delusion is a provocative and timely work. But Mearsheimer’s account of the political theories that underpin liberal hegemony is confused and in some respects plainly wrong, while the prospect of American policymakers converging on a consistently realist approach to foreign relations seems remote. One difficulty is that Mearsheimer bases his argument for realism on a misconceived dichotomy. For him, liberalism comes in two versions: progressive liberalism, which favours active government intervention in order to promote positive rights to welfare alongside negative freedoms from censorship and the like, and modus vivendi liberalism, which focuses on the protection of these negative freedoms above all else. Progressive liberals to have come to prominence over the past fifty years ‘include Ronald Dworkin, Francis Fukuyama, Steven Pinker, and John Rawls’. Modus vivendi liberals of recent times, Mearsheimer tells us, include myself and the American political theorist Stephen Holmes. In a longer time frame, ‘John Locke is a quintessential modus vivendi liberal, as are Adam Smith and Friedrich Hayek.’ It is flattering to be included in such distinguished company, but Mearsheimer’s analysis reflects a fundamental misunderstanding. No political theorist of whom I am aware would represent Locke, still less Hayek, as a theorist of modus vivendi liberalism. Both were classical liberals who prioritised negative freedom from coercion by the state over other freedoms and values. The progressive liberals Mearsheimer cites hold to a more positive conception of freedom that includes endowing people with the capacities needed for effective action. Such liberals recognise important rights to equality and welfare. Modus vivendi liberals do not fit into this dichotomy since they are ready to promote both positive and negative liberties if they can be shown to help individuals and communities with different beliefs and values to coexist productively in society. The canonical thinker of modus vivendi liberalism is not Locke but Hobbes, for whom all rights, other than the right to avoid a violent death, are subject to the overriding imperative of peace. Such a misunderstanding might not seem too damaging to Mearsheimer’s argument for realism, but it is not without consequences. Mearsheimer suggests that modus vivendi liberalism might offer a template for the kind of realist foreign policy he favours. Yet Lockean liberalism, which he invokes in support of his argument, sits uneasily with realism because Lockean rights are universal. For classical liberals as for progressive liberals, only one kind of regime can be fully legitimate: one that respects human rights, however defined. All other regimes are at best approximations of this ideal. Because its principles are supposed to be universally authoritative, Lockean theory has a built-in bias in favour of liberal hegemony. It is easy to move from the belief that liberal regimes are everywhere the best to the belief that existing liberal regimes have a duty to promote similar regimes throughout the world. (Modus vivendi liberals, by contrast, reject the idea that any regime could be the best for everyone.) Classical liberals have an inherent tendency to support what is now called liberal interventionism."