Ethnicity and strategy in the Bosnian civil war

The impact of ethnicity for the onset of conflicts has often been dismissed in the cross-country empirical literature on civil wars. Recently, however, several studies using disaggregated data have reached different conclusions and highlight the importance of the configuration of ethno-national groups. This article follows the latter approach and investigates a different phenomenon: the impact of ethnic heterogeneity on the severity of violence. Using disaggregated data at municipality level in Bosnia and Herzegovina, we perform a quantitative analysis to assess the impact of various indices of heterogeneity on the number of casualties that occurred in the 1992–95 war in the 109 municipalities composing the country. We argue that in a context where ethnicity plays a key role in shaping rivalry among groups, ethnic polarization, in particular, creates strategic incentives for severe violence as armed groups try to create ethnically homogenous territories in the first phase of the war. By also including the temporal dimension in the analysis, we show that ethnic polarization loses its impact as the war evolves over time; therefore, the geographic location of the municipalities becomes the best predictor of severe clashes because as the war goes on, ethnic groups shift their objective from creating internally homogenous municipalities to consolidating wider areas. As such, municipalities located on politically and militarily relevant frontlines experience the highest levels of violence.