Campaign Contributions and Roll-Call Voting in the US House of Representatives: The Case of the Sugar Industry

The question of whether campaign contributions buy roll-call votes is both important and contentious. Although researchers often find positive correlations between the two, it is difficult to conclude that these correlations are causal because interest groups may be simply giving to their supporters rather than attempting to change members' voting behavior. In this paper we use a pair of votes on antisugar subsidy amendments to investigate the causal effects of contributions on voting. With multiple votes we can control for the supportiveness of the district or member by using fixed effects. We find strong evidence that changing contribution patterns caused significant changes in the probability that a district or member would vote to support the sugar industry (i.e., against the amendments). Our results hold in both district and incumbent fixed effects models and also when we redefine the time window for measuring relevant contributions.