The Chemistry of Customary International Law : Assessing State Position Papers on International Law in Cyberspace as State Practice and Opinio Juris

In response to the growing legal uncertainty on international law in cyberspace - in absence of clear and effective rules in that domain - many States have published position papers outlining their views on how international law applies in cyberspace as part of a UN led dialogue. This thesis examines the legal significance of these position papers in relation to the two-elements test of customary international law. Namely, whether they can constitute State practice and opinio juris. Using the international legal method, the thesis first analyses these two elements in detail and identifies when verbal statements may qualify as State practice and opinio juris, to then apply the criteria to the position papers. For State practice, the thesis finds that factors like consistency, duration, and widespread conduct are primarily tailored to physical conduct and are less relevant for verbal statements. In-stead, to qualify as State practice, verbal statements must be attributable to States, preferably made in formal multilateral settings, and clearly describe or influence actual conduct. For opinio juris, the focus is on whether the statement expresses a legal belief by asserting existing rules in clear and precise terms. While alignment with conduct can strengthen opinio juris, it is not required as the two elements must be assessed separately. The aim here is not to determine whether a customary norm exists, but to what extent verbal statement can constitute State prac-tice and opinio juris. The analysis shows that while the position papers are attributable to States and issued in multilateral UN forums, they generally lack a concrete link to actual conduct. Even though verbal statements may carry more weight in areas like cyberspace, where conduct is difficult to observe, the language of the position papers fall short of describing or influencing action sufficiently to count as State practice. However, they clearly express legal beliefs by responding to calls by the GGE and OEWG to clarify existing international rules. Although alignment between practice and belief can strengthen opinio juris, it is not decisive for its existence. Thus, the position papers are strong indicators of opinio juris. The thesis concludes that while position papers alone do not constitute State practice, they significantly contribute to opinio juris and may therefore influence the development of customary international law in cyberspace.