This paper compares political activists from four community protest organizations, formed in response to the March 1979 accident at the Three Mile Island nuclear power plant.Using survey data, newsletters, and fieldwork, we document the existence of two separate paths to protest involvement. In two communities, recruitment was less likely to occur along the lines of established social networks. Instead, utilitarian alliances grounded on shared grievances were constructed.A second distinct path accounted for activism in two larger communities where many of the activists reported previous protest experience. In these communities, existing friendship networks were utilized.Two years after the accident, significant network and ideological differences between the groups persisted. We suggest that analysts work to specify the conditions for different paths to activism.