Introduction CHAPTER 1Although state sovereignty has become the bedrock of the international state system as we know it at the present time, this has certainly not always been the case throughout history (Krasner 1999, Philpott 2001. 3 Yet, it has become common in contemporary political thinking to attribute main governance practices and political authority to sovereign states. From that perspective, rebel groups are an illegitimate and relatively under-recognized governance actor. However, as the case studies in this dissertation show, rebel groups that fight against a sovereign state can themselves also be involved in governance and, thus, acquire political authority. These rebel groups are not internationally recognized states, but they do mimic many state functions that in contemporary history have become directly associated with the sovereign state. These functions include security provision, a judicial system, education, health care, taxation, infrastructure, and utility services. As a result, some geographical territories (for example Northeastern Sri Lanka between 1990-2009) were de jure considered to be part of a sovereign nation state (the Sri Lankan state in this case), but de facto ruled by a rebel group (the LTTE).Rebel governance is not an uncommon phenomenon. Approximately one-third of all insurgencies worldwide between 1945 and 2003 provided health care and/or educational services to the population under their control (Stewart 2014). From Latin-American leftist guerillas to Islamic groups in the Middle East and liberations movements throughout Africa and Asia, rebel groups have been involved in governance (see for example: Arjona et al., 2015). However, involvement in practices of governance is not self-evident for rebel groups. Governing is a costly endeavor filled with obstacles. The implementation of a judiciary system, the collection of taxes, and the provision of costly public goods demand sufficient resources, internal discipline, and coherence in strategy. In order to govern, rebel leaders must divert financial resources away from the military battle towards civilian governance efforts . This also requires rebel personnel that could have been used on the battlefield (Mampilly 2011, p. 62). Particularly under short-term military pressure rebel groups have fewer incentives to focus on a governance agenda, which almost inherently entails longterm investments and decisions (Arjona 2016, pp. 53-54). 4 For short-term gains, it may be more opportune for rebels to travel around and loot the population (Olson 1993). 5 Why then, do rebel groups become involved in governance?Civil war is the common context in which rebel governance takes place. Understanding rebel governance, therefore, requires a focus on the interactions between rebel groups and 3 The European tradition of thought in particular views the Peace of Westphalia in 1648 as an important transition from the dispersed authority of the Middle Ages to an international system of sovereign states (Philpott 2001, pp. 75-96). As a result of thi...