The last few decades have seen a lively philosophical debate surrounding human rights. Allen Buchanan's book The Heart of Human Rights constitutes an important and novel contribution to this debate, focusing on the moral dimensions of international legal human rights (ILHRs) and the institutions responsible for their existence and implementation. This represents a shift away from the more mainstream philosophical debates about human rights, which tend to focus on the nature and foundations of moral human rights (MHRs)—that is, the moral rights held by everyone simply in virtue of being human.

Buchanan's central purpose in The Heart of Human Rights is to construct a framework for assessing whether a system of international legal human rights that has all or most of the main features of the existing system can be morally justified. After providing a detailed characterization of the system, he argues that it can be morally justified in light of various benefits it provides and because it is necessary to offset a number of flaws in the international order. He goes on to defend the system against three potential challenges to its justifiability having to do with (i) the legitimacy of ILHR institutions; (ii) the apparent tension between constitutional democracy and international human rights law; and (iii) the significance of ethical pluralism.

The essays that follow were originally presented at a symposium on Buchanan's book at Nuffield College, Oxford, in 2015. The themes of the book served as a starting point for the authors, but each essay has been written as a stand-alone contribution to the literature.

Both Andrea Sangiovanni and Jesse Tomalty take up the justification of ILHRs. Against the orthodoxy, Buchanan argues that MHRs are of little relevance in the justification of ILHRs. Sangiovanni and Tomalty both challenge this claim and develop alternative accounts that assign MHRs a key role in the justification of ILHRs.

David Miller discusses the function of ILHRs. According to Buchanan, ILHRs serve to protect and promote both the wellbeing of individuals and their equal moral status. While Miller agrees that equality of status is an important value, he is doubtful that its promotion should be pursued through international human rights.

Pietro Maffettone and Lorenzo Zucca both take up what Buchanan refers to as “the problematic supremacy of international human rights law.” The problem according to Buchanan is that the claim of international human rights law to supremacy over domestic law is in tension with constitutional democracy. Both Maffettone and Zucca argue that Buchanan mischaracterizes the problem. According to Maffettone, the tension runs deeper than Buchanan acknowledges. And according to Zucca, international human rights law is in fact so weak that it does not exert any real force on domestic law.

Among the most important contributions Buchanan makes in The Heart of Human Rights is the provision of a framework for his project of analysing and morally evaluating the system of international legal human rights. Despite their disagreements with various aspects of Buchanan's account, the essays in this symposium all seek to further this project, and will be valuable to all those who share this aim.

—The Editors