Abortion politics affords an opportunity to examine how moral judgments are translated into collective action. Two approaches are examined. Cognitive developmental theory underscores moral development as a necessary condition of activism while rational choice theory emphasizes the necessity of appropriate incentive structures as a condition of participation in purposive organizations. Each theory is operationalized and the effects of moral development and organizational incentives on political activism are measured. Three significant conclusions emerge contradicting central tenets of each theory. First, moral development has no positive effect on any form of participation. Second, material and solidarity incentives, not normative incentives associated with the provision of a public good, have the strongest effect on abortion activism. Third, moral development significantly affects incentive choice, thereby having an indirect effect on political activism. The theoretical implications suggested by the findings are then discussed.Participation in social and moral reform movements is linked to a number of rational and cognitive determinants. As collective action, participation is analyzed as a function of rational utility calculations and organizational incentives (Eister 1989;Hardin 1982;Knoke 1988;Olson 1971). As moral action, participation is understood as a function of increasingly sophisticated cognitive development (Kohlberg and Candee 1984; Rest 1983;Haan et al. 1968;Merelman 1977;Nassi et al. 1983). Each methodology tells only one half of a complex story. Although rational choice theory has augmented the range of rationally compelling motivations with moral or normative incentives, the scope and content of these moral motivations are not fine-tuned, nor have the antecedent conditions of incentive choice been investigated. Moral development theory, on the other hand, delves into the cognitive conditions of action NOTE: The author is gratefully indebted to Richard Wilson as well as to the editor and three anonymous reviewers for their comments and suggestions on earlier drafts of this article.