Who controls the wealth? Electoral system design and ethnic war in resource-rich countries

• We test the interaction of electoral system design and natural resource wealth.
• We ask how this interaction influences the risk of ethnic civil war.
• We use binary time-series-cross-section analysis.
• Resource-rich countries with a proportional electoral system are less prone to ethnic civil war.

Both natural resource wealth and electoral system design are frequently investigated factors in the civil wars literature. So far, however, there is no well-known study which explicitly considers the interaction effect between these two factors on the risk of violent ethnic conflict. We argue that resource-rich countries with a proportional electoral system for the legislature are less prone to ethnic civil war than resource-rich countries with a majoritarian or mixed electoral system, as proportional electoral systems tend to increase the effective number of parliamentary parties and thus the number of groups who can share state control over resource wealth. We find empirical support for this argument using binary time-series-cross-section analysis covering 83 to 140 countries between 1984 and 2007.