AbstractUnlike studies that view democratization merely as free and fair competitive multiparty elections, this case study provides a subnational, socioterritorial analysis of the demise of single‐party rule in Chiapas, one of the last strongholds of the Institutional Revolutionary Party, revealing the contradictory and erratic processes of local politics in Mexico. Democratization requires not only regular alternation in office but also the development of representative institutions and of solid political parties that are able to constrain the executive branch. In Chiapas, electoral democratization occurred very late, with significant geographic variation, as the result of a convulsive process of political decomposition that included the indigenous Zapatista rebellion. Yet, corporatist structures and illiberal practices resisted, reproduced, and accommodated to electoral pluralism. The gradual erosion of the local “Revolutionary Family” spurred the fragmentation, and then the collapse, of the incipient party system, instead of fostering democratic governance with genuine checks and balances.