Evaluation of Political Party Cohesion Using Exponential Random Graph Modeling

摘要

The United States is becoming increasingly politically divided. In addition to polarization between the two-major political parties, there is also divisiveness in intra-party dynamics. In this paper, we attempt to understand these intraparty divisions by using an exponential random graph model (ERGM) to compute a political cohesion metric to quantify the strength within the party at a given point in time. The analysis is applied to the 105th through 113th congressional sessions of the House of Representatives. We find that the Republican party not only generally exhibits stronger intra-party cohesion, but when voting patterns are broken out by topic, the party has a higher and more consistent cohesion factor compared to the Democratic Party.