Territorial contenders in world politics

Territorial contenders are political entities that control territory but differ from sovereign states in that they lack diplomatic recognition as legal members of the international system. One consequence of this difference is that international relations data sets have historically excluded information about them. And yet, as evidenced by the Islamic State’s impact on politics in the Middle East and beyond, territorial contenders are important actors in the international system. In this article, we introduce a new data set of territorial contenders, compare territorial contenders to other categories of territorial nonstate actors, explore how the presence of territorial contenders affects the probabilities of civil war and state failure, illustrate the conditions under which territorial contenders are more likely to emerge, and discuss a series of studies now possible given the existence of this new data set.