Part 1: Cohesion

Abstract

Legislative party discipline and cohesion are important phenomena in thestudy of political systems. Unless assumptions are made that parties are cohesiveand act as unified collectivities with reasonably well-defined goals, it isreally difficult, if not impossible, to consider their electoral and legislativeroles usefully. But levels of legislative party cohesiveness are also importantbecause they provide us with crucial information about how legislatures/parliaments function and how they interact with executives/governments.Without cohesive (or disciplined) parties,1 government survival in parliamentary systems is threatened because executive and legislative powers are fusedwhile in separated systems presidents' bases of legislative support become lessstable. How do we explain varying levels of legislative party cohesion? Thefirst part of this article draws on the purposive literature to explore the benefitsand costs to legislators in democratic legislatures of joining and acting collectivelyand individualistically within political parties. This leads on to a discussionof various conceptual and empirical problems encountered in analysingintra-party cohesion and discipline in democratic legislatures on plenaryvotes. Finally, the article reviews the extant empirical evidence on how a multiplicityof systemic, party-levels and situational factors supposedly impactcohesion/discipline levels. The article ends with a discussion of the possibilitiesand limitations of building comparative models of cohesion/discipline.