Social movements occupy a shared ideational and resource space, which is often referred to as the social movement sector. This article contributes to the understanding of the relational dynamics of the social movement sector by demonstrating how ideational linkages are formed through protest events. Using a data set of protest events occurring in the United States from 1960 to 1995, the authors model the mechanisms shaping why certain movement issues (e.g., women’s and peace or environmental and gay rights) appear together at protest events. They argue that both cultural similarity and status differences between two social movement issues are the underlying mechanisms that shape joint protest and the resultant ideational linkages between issues. Finally, they show that the linking of issues at protest events results in changes in the prominence of a given issue in the social movement sector.
