When Does She Rebel? Explaining Vote Defection in the Mixed-Member Electoral System of Germany

Why and when do members of parliament vote against party line? Research explaining defective legislative behavior evolves around representatives’ strategic incentives shaped by electoral systems and party affiliations. Yet, surprisingly little attention has been paid to how individual-level factors influence choices to toe party line in case of West European parliaments. We argue that MPs make decisions based on their preferences, which are shaped by personal characteristics, most notably gender. Drawing on a newly released dataset of roll call votes of 17 legislative periods of the German Bundestag (1949-2013), we analyze whether male and female MPs respond differently to the strategic incentives they face. Our study reveals that context matters: while women have a higher likelihood to toe the party line, they increasingly rebel once the level of women’s representation rises, and in policy areas that disproportionally affect them, such as such as welfare policy, healthcare, or education.