This article analyzes the evolving mobilizational strategies of robust unions in contemporary Latin America. The origins of these strategies are rooted in the neoliberal adjustment policies in the early 1990s that compensated and reshaped power relations in labor organizations. With union compensation, a dominant faction concentrated power and embraced instrumentalism; the union exchanged electoral support with various parties for particularistic benefits. When adjustment policies were adopted without compensation, power was dispersed in an archipelago of activists. Unions then relied on movementism, which centered on contentious demand making and resistance to partisan alliances. Comparing teachers in Mexico and Argentina, this article contributes to broader debates about the effects of democracy on contentious politics and the changing partisan identities of workers.