Fighting corruption remains an ongoing challenge due to its multifaceted nature. This research examines (2008-2022) three regional governments in Spain (Valencia, Catalonia and Andalusia) with varying degrees of success in anti-corruption efforts, focusing on preventive reforms due to their limited powers for repressive measures, which remain a central government competence. To understand the disparities in accomplishment between them, complexity theory is used to look for leverage points for effective anti-corruption policies. Complexity theory provides a framework for understanding the unpredictable behavior of corruption and suggests that targeting strategic leverage points can effectively improve anti-corruption efforts, provided they fit the specific environment. This research shows that leveraging critical junctures with a holistic and disruptive strategy and the building of social empowerment were essential in reducing corruption in the Valencian case. Moreover, the study underlines that social empowerment is closely linked to a reduction in perceived corruption, both directly and through the mediation of trust in institutions. While the Valencian model offers valuable insights, each region must identify its own leverage points based on unique origins and path dependencies. However, the cases of Andalusia and Catalonia demonstrate that the key lever to significantly reduce perceptions of corruption and improve institutional trust has yet to be found. Further research is needed to understand the evolution of these systems.
