Strong parties and their alternatives: The structure of winning coalitions on the House floor.

다국어 초록 (Multilingual Abstract)

Drawing on the Responsible Party Government literature, this dissertation develops a new measure of party strength in the House—the Majority Party Strength (MPS) index—based not on partisanship but on the shape of the winning coalition and the affiliations of its pivotal members. It argues that the majority party is strong when it can engage in Single Party Legislating—the ability to ensure passage of whatever measures the caucus wishes. Since the majority party is not always successful in this regard, the dissertation defines alternative winning coalition structures as well and compares them with our current understanding of the changes in party strength and coalition structure since 1789. The dissertation reaches new conclusions about the causes of strong parties, the renewal of strong parties in the postreform House, and its impact on policy outcomes. For example, it finds that institutional variables explain the bulk of party strength, that unified government does not affect party strength but is necessary for non-median policy outcomes, and that Conditional Party Government began in the 1950s—at least fifteen years earlier than is generally theorized. The MPS index also helps resolve the empirical problem whereby roll call voting data are consistent with both a strong party model and a partyless model.