Incumbency Effects under Proportional Representation: Leaders and Backbenchers in the Postwar Italian Chamber of Deputies

We study incumbency effects for individual legislators from two political parties (Christian Democracy and the Italian Socialist Party) in Italy’s lower house of representatives over ten legislatures (1948–1992) elected using open-list proportional representation. Our analysis finds no reelection advantage for the average incumbent legislator. Only a tiny elite in each party successfully creates an incumbency advantage. We find incumbents advantaged for reselection by their political party. We interpret reselection advantage as a party loyalty premium. Our study depicts a political environment monopolized by party leaders who reward party loyalty but hamper legislators in appealing directly to voters.