The Portuguese Revolution of 1974 pawned a complex set of social movements. In general, the historical literature has tended the revolution as an epiphenomenon of major structural political change. This article analyzes the interactions and interdependencies between local collective action and institutional agents in the context of a study of socio-environmental conflict in the Portuguese inland region of Beira Baixa. The conflict involved a group of smallholding peasants against a mining company that opened an open pit mine close to the village. The motives that drove collective protest are examined in face of the structural political transformation processes, and the theory of collective action is used to observe how institutional agents acted and relied on local mobilizations to accomplish their political agendas.