A taxonomy of armed conflict

With some relatively minor exceptions international humanitarian law (IHL) applies only when a certain threshold is met: the existence of an armed conflict or belligerent occupation. The purpose of this chapter is to explore the many difficulties surrounding the classification of armed conflicts in modern IHL. While the two main archetypes – international armed conflict (IAC) and non-international armed conflict (NIAC) – are reasonably clear in their basic forms, their boundaries are complex and obscure. Many recent conflicts do not fit the classical archetypes well, provoking debates on spill-over, internationalized, mixed or hybrid and even transnational armed conflicts. The chapter strives to show that there are some differences between IACs and NIACs that cannot be erased simply by reasoning from analogy or from moral imperative, and that therefore the classification of armed conflict is an issue that matters and will continue to matter for the considerable future. The principal goal of the chapter is clarity, clarity in a conceptual and doctrinal framework which can enable legal and policy debates to be properly had and argued without their participants talking past each other. In attempting to advance such clarity, the chapter discusses the framework of war and peace in classical international law, the conceptual revolution brought about by the aftermath of the Second World War, and finally the modern law, by developing a comprehensive taxonomy of armed conflict.