Autonomous and/or institutionalized social movements? Conceptual clarification and illustrative cases

textabstractCase studies of urban squatting in the United States and the Netherlands, and the fight against sexual violence in Spain and in the Netherlands form the empirical basis of an analysis of the features and development of autonomous and institutionalized social movements, and the in-teraction between them. Autonomous and institutionalized social movements have different strengths that they derive from characteristics that are not compatible. Nevertheless, a dynam-ic is possible that combines the strengths of both models. It provides synergy between self-contained autonomous and institutionalized movements, without imposing trade-offs. Politi-cal opportunity theory suggests that such a ―dual-movement structure‖ is most relevant when the political system is selectively open. Interaction between the movements is conditioned by the mainstreaming potential of the issue or interest that is at stake. Even when relations are tense, movements can create opportunities for each other. Autono-mous movements are able to retain a repertoire of disruptive actions when lobbying is the more popular option. An autonomous movement can benefit from the legitimacy and support-ing network engendered by an institutionalized movement, pioneering work done by an au-tonomous movement can inspire an institutionalized counterpart. Autonomous movements can provide a critical voice when co-optation occurs