Excluded ethnic groups, conflict contagion, and the onset of genocide and politicide during civil war

Why do some governments commit genocide or politicide during civil war? It is well established that opposition groups learn from each other and that rebellion by one group encourages rebellion by others. Governments understand this dynamic. When a government excludes several ethnic groups from power, it worries that rebellion by one excluded group may invite challenges by other groups simultaneously. Therefore, when fighting one excluded group, increasing the number of additional excluded groups provides the government two incentives to engage in atrocity. First, the government hopes to ward off other challengers by demonstrating its brutality. Second, the government hopes to win its war quickly by destroying the rebels’ support base to reallocate its resources in case of further rebellions. Statistical analysis of all civil wars since 1946 reveals that governments fighting against the backdrop of additional excluded ethnic groups are more likely to commit genocide or politicide than other regimes.