Legitimacy of Transitions – Transitions of Legitimacy: Uncovering institutionalization dynamics in sustainability transitions

Legitimacy is of central importance for the establishment of technological and social innovations in sustainability transitions. The literature broadly conceptualizes the process of legitimating innovations as their alignment with institutionalized context structures. However, as transitions can be defined as (de)institutionalization processes themselves, they highlight the complexity of social orders. Therefore, this paper argues that legitimation not merely involves aligning with context structures, but rather the active and strategic social construction of legitimate relations between the innovation (object of legitimacy), the institutions (criteria for evaluation), and the evaluating actors. Building on this relational perspective, the paper develops a conceptual framework for analyzing legitimacy gaps – perceived inappropriatenesses concerning these relations – as constitutive entry points for legitimation and illegitimation strategies. The framework distinguishes two interrelated action spaces, in which these relations are dynamically constructed and stabilized: the evaluation space and the transformative action space. In these spaces, actors negotiate legitimacy gaps through a dynamic interplay of evaluation, challenge, and response, incrementally constructing (il)legitimacy relations. The framework is illustrated through the case of negotiations regarding the (il)legitimacy of wind energy installations in forested areas in Germany. By shifting focus from alignment to the interplay of micro-level actor dynamics, this paper advances institutional perspectives in transition research. By providing analytical tools to examine situational dynamics of (il)legitimacy constructions, it contributes to a deeper understanding of how innovations become established and (de)institutionalization evolves incrementally in sustainability transitions.