Antiwar movements mobilize in environments in which many of their potential supporters maintain loyalties to other social movements. Social movement organizations must find ways to attract supporters from these allied movements if peace demonstrations are to achieve critical mass. We argue that organizations with hybrid identities -those whose organizational identities span the boundaries of the antiwar movement and one or more other social movements -are vital to mobilizations for peace. Our analysis draws upon original data from surveys of 5,410 antiwar demonstrators conducted in 2007-2009, combined with publicly available data on 526 organizations that helped to mobilize them. Regression analysis using a two-stage mixed-process estimator shows that individuals with past involvement in non-antiwar movements are more likely to join hybrid organizations than are individuals without involvement in non-antiwar movements. Regression analyses using Tobit and Negative Binomial panel estimators establish that organizations with hybrid identities occupy relatively more central positions in interorganizational co-contact networks within the antiwar movement, and contact significantly more participants in demonstrations, than do their peer organizations. A movementlevel examination of the distribution of hybrid organizations helps to pinpoint some of the strengths and weaknesses in antiwar organizing. For example, numerous hybrid organizations form on the basis of gender and religious identities, but few organizations form to connect with environmental, African-American, and Latino activists. We conclude by proposing a broader research agenda on hybrid organizations, as well as on the role of individual biographies in social movements.
Keywords