Discipline and party institutionalization in post-Soviet legislatures

Fearing that weak or poorly institutionalized party systems may undermine democratic consolidation, scholars have examined party systems in a myriad of contexts. The vast majority of these studies utilize aggregate measures of party system institutionalization to assess the relative merits of individual systems. While laudable, relying on aggregate measures may obscure the effects of the variation in party institutionalization in different systems. This article examines legislative politics in post-Communist Russia and Ukraine to determine whether variation in party institutionalization, even in weakly institutionalized party systems, has significant effects. The empirical results show that variation in party institutionalization creates variation in levels of parliamentary party discipline in both contexts. This raises the possibility that systemic level analyses of party system institutionalization are ignoring the effects of within-system variation.