This study argues that organizationally stronger local party branches are more powerful within the party than organizationally weaker branches: they can better perform the tasks central to the party, which include communication with, and mobilization of, voters. I further argue that this subunit power should be manifested in the parliamentary behavior and status of MPs: those from districts where the local party organization is strong are more likely (1) to behave independently in parliament and break party unity and (2) to hold leadership positions in parliamentary committees. I find support for these propositions in the analysis of 12 legislatures from four postcommunist democracies-Czech Republic, Estonia, Hungary, and Poland. The results remain robust against various alternative explanations.H ow is power distributed within political parties and what are the effects of the power distribution? These questions, and the internal workings of parties in general, are relatively unexplored in the otherwise voluminous literature on political parties. It is common to treat parties as unitary actors and ignore their internal diversity despite frequent calls to account for it (Laver 1998;Laver and Schofield 1998;Strom 1990). At the same time, parties' internal power distribution is important for understanding the dynamics of party behavior. Knowing which party subunits or individuals are more influential or more independent can give us clues about party policy choices, position taking, electoral campaigns and performance, interparty relations, coalition decisions, representational linkage types, restructuring attempts, and the like, i.e., the aspects of party politics that are extensively studied by political scientists but so far mostly from the unitary actor perspective. 1 This study explores the power distribution within political parties by borrowing insights from organizational theory. Literature on organizational sociology suggests that power within organizations is asymmetrically dis-