Constituency Effects and Legislative Dissent under Closed-List Proportional Representation

Abstract

According to conventional wisdom, closed-list proportional representation (CLPR) electoral systems create incentives for legislators to favor the party line over their voters' positions. However, electoral incentives may induce party leaders to tolerate shirking by some legislators, even under CLPR. This study argues that in considering whose deviations from the party line should be tolerated, party leaders exploit differences in voters' relative electoral influence resulting from malapportionment. We expect defections in roll call votes to be more likely among legislators elected from overrepresented districts than among those from other districts. We empirically test this claim using data on Argentine legislators' voting records and a unique dataset of estimates of voters' and legislators' placements in a common ideological space. Our findings suggest that even under electoral rules known for promoting unified parties, we should expect strategic defections to please voters, which can be advantageous for the party's electoral fortunes.