Why do communal conflicts turn violent in some regions but not in others? Communal conflicts pose a severe threat to human security and kill thousands of people each year, but our understanding of this phenomenon is still limited. In particular, we lack knowledge about why some of these conflicts become violent while others are resolved peacefully. This study addresses this knowledge gap and has a novel approach by addressing subnational variations that are unexplained by previous research. The theoretical framework combines insights from three different perspectives focusing on the role of the state, elite interactions, and conditions for cooperation over common resources. Empirically, the research question is investigated by combining within- and between-region analyses of three Sudanese regions: Darfur, Eastern Sudan, and Greater Upper Nile. Despite sharing several similar characteristics, communal conflicts have killed thousands in Darfur and Greater Upper Nile but only a few dozen in Eastern Sudan. The empirical analysis builds on extensive material collected during fieldwork. This study generates several conclusions about the importance of government conduct and how state behavior contributes to the prevalence of violent communal conflicts. It finds that when governments act in a biased manner – favoring certain communities over others – interactions between central and local elites as well as among local elites are disrupted. Unconstructive elite interactions, in turn, have negative effects on three mechanisms that are crucial for communal cooperation. First, when the regime is biased, communal affiliation, rather than the severity and context of a violation, determines the sanctions that are imposed on the perpetrators. Second, government bias leads to unclear boundaries, which contribute to violent communal conflicts by creating disarray and by shifting power balances between the communities. Third, regime partiality distances rules from local conditions and restricts the influence of local actors who have an understanding of local circumstances. The study also reveals why a regime acts with partiality in some areas but not in others. The answer to this question is found in the complex interplay between the threats and opportunities that a region presents to the regime. Taken together, the findings have important implications for the prevention and management of communal conflict.