Women and Power: Unpopular, Unwilling, or Held Back?

We delineate three mechanisms that could explain women's under-representation in electoral lists and political power: voter demand, candidate supply, and internal party dynamics. We use Spain's Equality Law, which mandates a 40 percent female quota on electoral lists, to test these alternative theories. The law was enacted by the Social-Democratic Party after the surprise parliamentary electoral results following the Madrid terrorist bombings in 2004. It was therefore completely unexpected by local political organizations. The quota only applied to towns with populations above 5,000 and forced heterogeneous growth in the number of female candidates by party. Using preand post-quota data by party and municipality, we implement a triple-di erence design and nd that female quotas resulted in slightly better electoral results for the parties that started out with fewer women, and hence were most a ected by the quota. Our evidence is not consistent with the existence of pro-male voter preferences, or with the hypothesis that the best female candidates e ectively available to the parties displayed poor quality as politicians.