Political systems,stability and civil wars

In this paper we analyze theoretically and empirically the stability of the different political systems; that is, their ability to prevent conflict. According to our model, the proportional system has a lower probability of group rebellion than the majoritarian system. In the empirical part we test the role of political systems in preventing civil wars. We show that democracy by itself does not play an important explanatory role, while the specific type of political system-majoritarian, presidential and proportional-does. The rationale of this result is that different political systems entail different opportunity costs of rebellion.