Soft law, hard stakes? State commitment to non-binding international instruments and the case of the UN Declaration on the Rights of Indigenous Peoples

Soft law is a common feature of international governance, occupying a grey zone between the realms of politics and law. The multifaceted concept can refer to vague provisions or norms generally, but is most useful when defined as international instruments adopted in a non-binding form. Whilst the advantages and appeal of soft law have been widely studied, with its effects explored in both International Relations (IR) and International Law (IL) scholarship, states’ behaviour on commitment to soft law per se has remained underexplored. It is often assumed that its non-binding status upon adoption makes commitment to soft law a relatively inconsequential endeavor, at least in comparison to hard law. In this thesis, incorporating insights from public international law into rationalist IR approaches, I argue that soft law instruments can have important effects over time and bring substantial costs for states to bear. This is particularly the case for soft law instruments ‘hardening’ through domestic law, treaties or customary international law, increasing the sovereignty and implementation costs attached to commitment. I further argue that those potential costs of soft law are taken into account by states when making decisions on commitment. Depending on the importance and likelihood of the costs foreseen, states can craft their commitment to mitigate these costs or block them from arising. Empirical evidence for the place of the costs of soft law in states’ decision-making on commitment is offered through an in-depth case study of the UN Declaration on the Rights of Indigenous Peoples, with a focus on the opposition it faced upon adoption – an unusual occurrence for a UN declaration in the field of human rights. Recognizing the potential costs of soft law and their impact on state commitment helps to bridge theory and practice regarding the creation of non-binding instruments and sheds light on challenges raised by the use of soft law by states and non-state actors at the frontiers of international law-making.