Subsidiarity in International Human Rights Law—What is Subsidiary about Human Rights?

Subsidiarity is en vogue in international human rights law. From a largely implicit and mainly jurisprudential principle used in discrete guises by international human rights courts, it has become increasingly present in human rights reasoning and is about to become entrenched in the text of international human rights treaties. Past the usual truisms about States having the primary responsibility to secure human rights and international human rights institutions having only a supervisory function, however, the notion, role and justification of subsidiarity in international human rights law remain very difficult to capture. Broadly speaking, scholarly strategies have divided into two groups. Most authors focus on one aspect of subsidiarity (usually the margin of appreciation of domestic authorities), while fewer look for the broader underpinning principle. The former often neglect the broader question, however, while the latter have often been lured by one dimension of the prestigious history of the principle of subsidiarity and conflate subsidiarity in international human rights law with one or many of its different conceptions in other legal and political contexts (e.g. in a federal state or in the European Union). In this article, I argue that the concept of subsidiarity is at play in international human rights law, but that human rights subsidiarity is very different from the other conceptions of subsidiarity we know of. To understand it, we need to go back to the relationship between human rights and (democratic) politics and, accordingly, to the role of international human rights law and its complementary relation to domestic human rights law. The proposed argument is three-pronged. After a first section on subsidiarity in international human rights law and the different shapes it takes in practice, the second section compares human rights subsidiarity with the subsidiarity encountered in other social, political and legal contexts, and does so with respect to different dimensions of subsidiarity: its subjects, objects, functions, justifications, tests, limits and reviews. The third section draws various implications of the specificity of human rights subsidiarity, and in particular for how we should go about interpreting it and addressing some of the challenges it is currently facing in practice.