The ideological cohesion of parliamentary parties and its implications for decision-making in modern democracies

Abstract

Political scientists often treat parties as “unitary actors”. In most cases, however, parties represent divergent interests of various members in several regional and organizational units. This project aims at measuring the ideological cohesion of political parties, that is, the general agreement within a party in terms of policy positions. In addition, the project aims at exploring the causes and consequences of ideological cohesion. We explain varying levels of intra-party cohesion taking individual characteristics of MPs and ministers as well as country- and party-specific institutional factors into account. Moreover, the project explores the manifold implications of intra-party cohesion on legislative decision-making, government formation, and policy-making in general. It is argued that intra-party cohesion or its opposite, heterogeneity has consequences for the power and behavior of political actors, for example when forming governments and allocating ministerial portfolios. Furthermore, intra-party cohesion should have wider consequences on political outputs. Focusing on nine Western European countries (Austria, Belgium, France, Germany, Italy, the Netherlands, Spain, Sweden, and the United Kingdom), we analyze parliamentary speeches of members of Parliament (MPs) and cabinet members by applying computerized methods of content analysis. Understanding the causes and consequences of intra-party cohesion is important for the performance of political parties, governments, ministers and MPs, and democratic systems as a whole.