ABSTRACT
This chapter examines the legitimacy and binding nature of the obligations of Non-state armed groups (NSAG) under established international law, as well as ad hoc agreements and more initiatives that challenge the definitions of ‘legal’ and ‘non-legal’ regulation. It explains the transnational nature of the topic and offers working definitions of NSAGs and legitimacy and considers the extent to which international law applies to NSAGs. The rationale for the application of the law of armed conflict is examined, before turning to the question of whether international human rights law could also apply. The chapter addresses informal means of engaging with NSAGs that could potentially result in binding such groups to international human rights or humanitarian norms. It offers an examination of the relationship between legitimacy and formality in determining the sources and application of the law. The legitimacy of the instruments themselves, and the substantive norms that they contain, is also a source of contention.
