This paper seeks to clarify the confusions regarding the relationships between international human rights law and international humanitarian law, the principle of equality of belligerents, and the use of the term “should” in treaties. For this purpose, it examines, as a case study, the Optional Protocol to the Convention on the Rights of the Child on the Involvement of Children in Armed Conflict, on which doctrine is divided whether Article 4(1) thereof is binding on armed non-State actors. First, this paper reconceptualizes international humanitarian law as a subset of international human rights law, which share the same purpose, mutually reinforce, and depend on each other. Second, drawing on the customary rules of treaty interpretation under the Vienna Convention on the Law of Treaties and through a comprehensive analysis of the authentic texts in other languages and the travaux préparatoires, it argues that the term “should” in the operative part of treaties always creates legally binding obligations and that the equality principle does not strictly apply to norms applicable during peacetime. As such, despite its use of “should” and differential treatment between States and armed non-State actors, Article 4(1) of the Protocol creates a direct human rights obligation on armed non-State actors.
Armed Non-State Actors and International Human Rights Law: An Analysis of the Practice of the U.N. Security Council and the U.N. General Assembly
