Concentrated Party Systems and the Normative Theory of Partisanship

Abstract This chapter evaluates concentrated party systems (i.e., two-party system and predominant party system) based on the normative theory of partisanship. More specifically, it analyses the properties of these party systems, as well as several variants (or subtypes) within them, in order to assess the extent to which they each foster or hinder collegiality, systemic voice, and systemic accountability. The party systems are ranked along a scale from ‘very low’ to ‘very high’ in each of these dimensions (with the intermediate positions on this scale being ‘low’, ‘medium-low’, ‘medium’, ‘medium-high’, and ‘high’). The analysis reveals that two-party systems generally present low levels of collegiality and systemic voice but a medium-high level of systemic accountability. In the case of predominant party systems, collegiality is very low, while systemic voice is low and systemic accountability is medium-low.