External support in armed conflicts: Introducing the UCDP external support dataset (ESD), 1975-2017

In this article, we present the most up-to-date, fine-grained, global dataset on external support in armed conflicts: the UCDP External Support Dataset (ESD). The dataset encompasses data on states and non-state actors as both supporters and recipients and provides detailed information on the type of support provided to warring parties in armed conflicts between 1975 and 2017. We use it to highlight three broader trends in the provision of external support: (1) a dramatic increase in the number of external supporters, (2) a larger share of pro-government interventions, and (3) the rise of direct military intervention as the predominant mode of external support. In conclusion, we identify several avenues worthy of future inquiry that could significantly improve our understanding of external support in armed conflicts.