Party organizational strength and party unity in post-communist Europe

The existing comparative literature focuses on political institutions to explain party unity in parliament, and largely ignores the role of party characteristics in this process. This study argues that the strength of political party organization directly and independently influences the level of party unity. Organizational strength makes the party a valuable asset to individual legislators, thus increasing their willingness to be disciplined. Therefore, parties with strong organizations are likely to be more unified in parliament than those with weak organizations. I find support for this argument with data from four post-communist democracies: the Czech Republic, Estonia, Hungary, and Poland. Narratives suggest that the proposed causal mechanism is plausible.