This article examines the impact of organizational structure on party behavior in the context of Franz Müntefering's resignation as SPD Chairman in late 2005. Conceptually, it argues that party organizations embed institutionalized rules that govern internal hierarchies and shape party decision making. Because party organizations are created under different circumstances, the rules governing their internal hierarchies and decision-making behavior may vary. This analysis suggests why such differences can persist for decades even when they produce such unintended-and undesirable-consequences as the embarrassing resignation of a popular chairman in the middle of a coalition negotiation.