The Role of Trade Unions in Environmental Governance: Exploring Workers Legitimacy Judgments

ABSTRACT Trade unions are increasingly expected to play a role in sustainability transitions, but their legitimacy as environmental governance actors remains underexplored. Our study uses a multidimensional framework to examine how workers, both union members and non‐members, evaluate trade union legitimacy “from below.” This framework distinguishes between normative legitimacy, based on environmental values, and instrumental legitimacy, reflected in perceived dual‐mandate capability. Survey data from Slovenia reveal robust normative support for union involvement in sustainability, fueled by environmental concern. In contrast, instrumental legitimacy is more conditional and closely linked to union membership. Interestingly, non‐members with high environmental concern express even stronger expectations for union involvement than members do. These findings suggest that legitimacy is co‐constructed through value alignment and perceived effectiveness rather than inherited from institutional status. By centering worker perceptions, we contribute to environmental governance scholarship by positioning unions as civic actors whose legitimacy is formed “from below” and to legitimacy theory by showing how internal and adjacent publics assess unions' purpose and performance, suggesting that these evaluations may condition unions' authority claims in contested transitions.