Rational Mobilization of Ideological Group Members in Elections : Theory and Evidence

Abstract

We re-examine the link between group membership and turnout. While recent theoretical work in the rational choice tradition emphasizes the importance of groups, such as political parties and informal social networks, for turnout, it has paid little attention to formal economic groups like labor unions. We argue that this has hampered scholars' ability to make sense of unions' electoral impact. Theoretically, we show that rational mobilization implies that the link between union membership and turnout varies by individual ideology and electoral competitiveness. This suggests that the common empirical approach of estimating the average union vote premium can lead to misleading inferences. Analyzing American national election surveys combined with state-level data between 1964 and 2008, we find strong evidence consistent with rational mobilization by unions. Competitiveness increases turnout among left-leaning union members rather than all members, and left-leaning but non-unionized individuals are less affected by competitiveness.