The Causal Effect of Parliamentary Breakthrough on Party Supporters’ Moderation

• In Event: Public Attitudes and Confidence in Democracy

Abstract

Gaining parliamentary representation is one of the first steps in the institutionalization of a political party. Representation in the national legislature gives access to several resources, from financial support to media attention. Participation into parliament also makes parties more accountable and responsible, discouraging outbidding and fostering moderation. New parties are often more radical, collecting protest votes of people who do not feel represented by current competitors. Still, entering parliament can be seen as a recognition of the legitimacy of the party. Accordingly, I argue that it could help decrease supporters’ dissatisfaction with the system and water down their most radical views. This paper identifies the causal effect of parliamentary breakthrough on the ideological moderation of party supporters. This potential is still uncovered by political science literature, that has so far only assessed the effect on the moderation of rival parties or on polarization in the electorate. In most European countries, to obtain seats in the national parliament an electoral threshold needs to be reached, which I will exploit in the form of a regression discontinuity design. The data will be taken from the Comparative Study of Electoral Systems and Manifesto Project datasets. The scope of the paper will include 17 European countries since 1996, providing a comprehensive causal analysis of the effect of parliamentary breakthrough on party supporters’ moderation.

Author

• Sofia Marini, University of Vienna