Party Central: Networks, Influence, and Party Change in the US House of Representatives

For decades, scholars have devoted considerable attention to the causes and processes of party change. In this dissertation, I offer a new theoretical framework that not only takes into account the behavior of Members of Congress, but also how that behavior is constrained and conditioned by the relationships they share with other Members. This web of relationships forms a party network, the structure of which changes as Member-to-Member relationships change over time. I also identify three mechanisms of party change: a Member of Congress shifting their position to align with another (assimilation); a Member being pushed to the periphery of the network and exiting professional politics (marginalization); or a Member of one faction being targeted for a primary challenge by someone of another faction (opportunity). I argue that each of the mechanisms is more likely to occur under certain types of network structures. When analyzed independently of structural conditions, I find modest support for assimilation, strong support for marginalization, and no support for opportunity. However, when structural effects are introduced, neither assimilation nor marginalization perform as predicted. Opportunity, on the other hand, becomes highly significant under factional conditions