Development is not an all-powerful machinery imposing its will upon powerless actors. Rather, it is a complex process that brings together multiple actors with diverse agendas. Participants' power in affecting outcomes results from their ability to mobilize discursive and material resources and to control and manipulate time and spatial contexts. This work critically examines development practices and various forms of collective action based on detailed ethnographical analysis of the Yacyretá hydroelectric project. The story unfolds in the borderlands of Paraguay and Argentina in the heart of the Latin American Southern Cone where local political cultures are responding to global forces that now dictate economic integration. Although relatively unknown today to the world, this area promises to exert a strong global impact in the near future.The saga of the Yacyretá hydroelectric project on the Argentina-Paraguay border not only illustrates the radical change in the power dynamics of the Latin American Southern Cone region, but also reflects the transformation of development discourse and practice during the last decades. It examines the relationship between the weakened role of the nation-state in decision making and the emergence of nongovernmental organizations and grassroots movements as key development actors. Because the Yacyretá dam is being built in the borderlands of two countries as a binational undertaking, it threatens the boundedness of nation-states precisely where sovereignty is traditionally guarded-the national frontiers. Under these and other global challenges of deterritorialation such as processes of regional integration encouraged by Mercosur (Common Market of the South), popular conflicts have become spatialized, reflecting both the resilience of national imaginings and histories of exclusion and exploitation.This study demystifies populist and romanticized academic constructions of subaltern groups. It shows that the outcomes of popular struggles can be one of accomodation and cooperation and not resistance. Nonetheless, they constitute serious threats to planned development. It challenges current approaches in development that advocate participation, empowerment, and communication.