Abstract

The economic and political literature widely studied the effects of electoral system on corruption. But very little attention has been dedicated to the role of political competition in explaining this relationship. We hypothesize that the proportionality degree of the electoral system impacts corruption directly and in a conditional way: through the degree of electoral competition among political parties. The estimation results, on a sample of the 20 Italian regions over 26 years, show that both the direct and the indirect effect matter in explaining corruption. As the electoral system becomes more proportional, corruption directly decrease. This beneficial effect can be reinforced or depressed depending on how political competition reacts to changes in the proportionality degree of the electoral system.