Influence in the United States Senate

Interpersonal influence is an important, yet difficult to measure factor mediating legislative outcomes in the United States Congress. Building on theories that conceptualize a legislator's influence as an individual property, I cast influence in a relational framework, recognizing that influence is exercised through legislators’ social and political networks. I develop a novel measure of legislative influence using temporal patterns in bill cosponsorship data as an instrument to infer a latent network of influence relationships between legislators. I then validate the measure of legislative influence I derive from these networks in several contexts. For example, scholars have observed a decrease in the power of committee chairs relative to party leadership over time, yet existing quantitative measures of interpersonal influence do not agree with these findings at a micro level. I find that my measure performs like an effective measure of interpersonal influence in Congress.