Collective action lies at the heart of any vibrant civil society because civic engagement requires individuals to work together as part of a group. In plural societies, political parties, interest organizations, voluntary associations, and religious congregations serve an important role. Putnam et al. (1994) said these associations all help to “make democracy work.” Meyer and Tarrow (1998) characterize contemporary postindustrial societies as “social movement societies” in which interest organizations and protest groups are nearly ubiquitous. Too often, however, collective action is taken for granted by civic activists and prescriptive theorists of civil society alike. It is easy to assume that, because people belong to groups with common interests, the members of that group will act in concert to achieve those interests. These assumptions are challenged by collective action theory.