The Mexican automobile manufacturing industry experienced rapid sociopolitical change in the 1960s and 1970s as workers in several firms overthrew entrenched labor leaders and instituted democratic forms of union governance. These reform movements sought increased participation by the rank and file in union affairs and heightened worker control over different aspects of the production process. For many workers, democratic unionism promised increased leadership responsiveness in resolving workplace conflicts and more effective representation of worker interests in a changing industrial environment. Specific measures of democratic unionism included the election of key union officers and their accountability to members, regularly held general assemblies, an enhanced role for the general assembly in internal decision making, procedural safeguards of workers' union rights, and opportunities for the emergence of identifiable and relatively stable internal opposition factions. By 1975 workers in five of the seven major terminal firms (those manufacturing vehicles) had won control over the selection of union leaders and other phases of internal union decision making.