Recent work on power sharing and civil conflicts in ethnically divided
societies emphasizes the crucial distinction between mandates and
their implementation. Formal power-sharing rules reduce the risk of
armed conflict, but power-sharing practices mediate this effect. Some
scholars argue that proportional electoral systems belong to the
broader class of power-sharing institutions and lead to
power-sharing practices, which in turn reduce the likelihood of
intrastate armed conflict. Empirical evidence for this claim is
indirect at best. Using mediation analysis, we comprehensively assess
whether PR rules alone or their combination with other formal
power-sharing institutions engender elite power sharing, and thus
reduce the chances of intrastate conflict. The results suggest that PR
does not have this general positive effect on power-sharing practices
and thus does not complement the conflict-reducing effect of
formal power-sharing institutions.