Party Status to Armed Conflict in International Law

Parties to armed conflict are referred to in hundreds of provisions in international treaties and are also, for example, frequently addressed by international bodies, such as the UN Security Council in resolutions on situations of armed conflict. Despite this prominence, little attention has been paid in international law scholarship to the concept of party status in armed conflict. However, determining which entities qualify as the parties to an armed conflict and which legal consequences flow from this status can raise complex challenges, in particular as armed conflicts have always been and are increasingly fought in different forms of cooperation. These forms of cooperation range from joint missions to various forms of coalitions or looser partnerships of support and involve diverse types of entities—States, international (governmental) organisations, as well as non-State armed groups—to varying degrees. 

Against this background, the thesis aims to shed light on the concept of party status in armed conflict under international law by answering a two-fold research question: which legal criteria determine when entities cooperating in armed conflict become parties to the conflict under international law and which international law implications follow from this status? 

The thesis is divided into three parts. In the first part, the thesis explains why and how it matters from an international law perspective to identify the parties to an armed conflict. The second part of the thesis investigates how international law determines whether and when entities cooperating with partners in military operations become parties to an armed conflict under international law. In the third part the thesis brings together and further develops the findings of the first and second parts by exploring whether and to what extent there are or could be cooperation-specific implications of (co-) party status.