Searching for Armed Non-state Actors’ Role in the Process of Formation of Customary Law

Summary The paper explores the problem of the formation of the ‘(quasi-) customary law’, as a source of law created by, or contributed to by armed non-state actors (ANSAs). It argues that, despite some views presented in the doctrine of international law, claims of a quasi-customary international law are without foundation in the current state of international law. The paper is divided into three parts. The first part presents the views of legal doctrine concerning the customary law as contributed/created by non-state actors. The second section argues that ANSAs do not form practice and opinio juris which would allow them to create their ‘own’ customary law. The final part presents the possible challenges and consequences of including ANSAs in the process of formation of customary international law as created by States. In summary the conclusions posit that it could be potentially very harmful for international humanitarian law and the protection of human rights.