This chapter discusses Mexico’s subnational democratization process as an entangled process where formal institutions become entangled with informal rules, structures, and practices to produce diverse outcomes. It analyses three major domains where formal democratic institutions interact with locally embedded traditions and practices – political dynasties, double-dealing, and democratic delinquencies. The chapter makes two main contributions to the literature on subnational democratization and to the study of formal and informal institutions. First, it provides a conceptual framework to understand subnational democratization processes as complex and unstable processes that encompass both formal and informal institutions, and their entanglements with often illiberal local structures and practices. Second, it provides exemplary illustrations of such entanglements in a range of contemporary subnational Mexican settings, using evidence from the three domains just indicated.