Democratic transitions represent unique opportunities in which movements of the poor can coalesce, place their demands on the national agenda, and institutionalise their access to authoritative decision-making centres. The opportunities and constraints movements of the poor face during transitions, however, remain little understood and under-theorised. This study develops an analytic approach that links national-level democratisation processes to the local-level movement dynamics that make collective action possible, particularly the creation and reproduction of collective identities and organisational structures. The approach theorises how changing elite alliance patterns during transition cycles, and redefinition of institutional linkages that bind state and society, shape the opportunities and constraints movements face at successive stages of democratic transitions. The utility of this approach is demonstrated by examining the new unionism in rural Brazil, in that country’s democratic transition during the 1980s.