The most useful forms of outside support for an insurgent movementinclude safe havens, financial support, political backing, and directmilitary assistance. Because states are able to provide all of thesetypes of assistance, their support has had a profound impact on theeffectiveness of many rebel movements since the end of the Cold War.However, state support is no longer the only, or indeed necessarily themost important, game in town. Diasporas have played a particularlyimportant role in sustaining several strong insurgencies. More rarely,refugees, guerrilla groups, or other types of non-state supporters playa significant role in creating or sustaining an insurgency, offeringfighters, training, or other forms of assistance.This report assesses post-Cold War trends in external support forinsurgent movements. It describes the frequency that states, diasporas,refugees, and other non-state actors back guerrilla movements. It alsoassesses the motivations of these actors and which types of supportmatter most. This book concludes by assessing the implications foranalysts of insurgent movements.