Voting Against Your Constituents: How Lobbying Biases Representation

Citizens delegate the representation of their political preferences to Members of Parliament who are supposed to represent their constituents interests in the legislature. The congruence of citizen preferences and legislative behavior of their parliamentary deputies is crucial for the quality of representation in a democracy. However, Members of Parliament are exposed to a variety of interest groups which seek to influence MP voting behavior in the legislature in their favor. In this paper, we study the consequences of interest group lobbying for the congruence between voter preferences and legislative behavior of their representatives. We argue that interest groups bias representation since they supply valuable resources to politicians such as monetary contributions (allowances or campaign donations) or information which causes MPs to defect from their constituents. We test our theoretical argument based on an innovative study of 118 Swiss public referenda which at the same time, have been put to vote in the legislature so that we can directly compare issue-specific constituent preferences with legislative voting of 451 MPs on these issues. Given that the Swiss legislature also requires all MPs to declare their interest group affiliations, we are able to examine whether MPs with strong interest group ties are more likely to defect from the preferences of their constituents. Our findings will have important implications for our understanding of political representation.