This chapter reflects on the last decade of scholarly reflections on the question of non-State actors and customary international law and revisits some of the specific argumentative constructions and presuppositions that have informed – and continue to inform – discourses on the contribution of non-State actors to the formationof customary international law. It is argued here that three tropes have been mechanically repeated in previous rounds of scholarly debates on non-State actors and customary law. These constructions can be summarised as follows: the idea that the two-element variant of the doctrine of customary international law originates in article 38 of the Statute of the Permanent Court of International Justice; the continuous attachment of international lawyers – including the International Law Commission – to the distinction between practice and opinio juris; the understanding of the concept of non-State actors as a plain and innocent descriptive category.