The Geographical Reach of International Humanitarian Law in Transnational Armed Conflict

Non-international armed conflict between States and organised armed groups is a reality of warfare. Since the emergence of the 1949 Geneva Conventions, this form of conflict has been regulated by international humanitarian law. However, a subset of this category known as ‘transnational armed conflict’ has seen aggressive proliferation over recent decades as groups such as the Islamic State of Iraq and Syria have taken advantage of the internet and other technologies to expand their reach beyond national frontiers and strike States around the world. This phenomenon has left the geographical extent of international humanitarian law – which has historically relied on State boundaries to determine its ambit – unclear. This article examines the main options for delimiting the geographical reach of the regime in transnational armed conflict. It considers approaches based on international boundaries; ‘hot battlefields’; ‘global application’ and ‘territorial control’ before ultimately concluding that a method based on ‘military presence’ would be the most suitable standard.