Parliamentarians and Party Groups: The Role of Intra-Party Unity

Parliamentary democracies show little variance in party unity because the vast majority of parliamentarians vote in near perfect unity with their party on recorded votes. Legislative scholars are thus presented with a paradox: In those systems where party unity is most needed, it is the hardest to study. The focus of this chapter is on the elected representatives of the party, the party’s Members of Parliament (the parliamentary party group). This chapter addresses the importance of party unity in parliamentary democracies, as well as the conceptual confusion surrounding party unity. It presents a new model for assessing party unity that begins to solve the puzzle of how to explore party unity when near perfect unity is recorded in parliamentary voting, and delineates the recent developments in research on party unity. It concludes by proposing an agenda for future research.