Explaining Legislative Extremity: Examining the Effect of Electoral and Campaign Constituencies on Legislative Behavior in the US House

There have been many studies that have attempted to explain why members of Congress vote the way they do. Previous studies of legislative behavior have looked at both roll call votes and other measures of position taking and have found that this behavior can be explained by a combination of constituency, party, and interest group influence. The literature has not yet adequately addressed, however, whether members' roll call voting behavior is driven to a larger degree by campaign donations or by the member's electoral constituency. Members of Congress are beholden to both constituencies in some way, and because these two constituencies may at times place different demands on a legislator it is important to investigate which group has greater pull when the legislator is determining how to vote on a bill. Using new data that estimates the ideology of a member of Congress using the campaign finance donations a member receives during their election campaign, along with measures of the ideology of different electoral constituencies from the Campaign Congressional Election Study in the 111th and 112th Congresses, we find that roll call voting is most driven by party affiliation and the ideology of a member's contributors. These findings hold for a number of subgroups, including Democrats, Republicans, freshmen, and incumbents. We also explore the consequences this finding could have for representation in Congress.