["The British Journal of Sociology, EarlyView. ", "\nABSTRACT\nBased on ethnographic fieldwork in Mexico and judicial wiretap analysis in Argentina, this paper shows that collusion between state actors and violent non‐state actors operates through fluid and competitive relational networks rather than stable hierarchies or fixed institutional arrangements. In Mexico, private security entrepreneurs broker ties between public officials, clients, and violent specialists, particularly during periods of electoral competition. In Argentina, criminal organizations and state agents develop shifting alliances that shape drug market regulation and patterns of violence. Across both cases, collusion depends on the continuous negotiation of trust, access, and information across overlapping networks embedded within state institutions. We argue that these patterns cannot be fully explained by frameworks that treat collusion as a legacy of authoritarianism or as a product of institutional weakness. Instead, collusion emerges as an adaptive relational process shaped by competition among actors and the instability of contemporary security governance. These dynamics produce fluid and contested “gray zones” in which legality and illegality are continuously reconfigured, with direct implications for how violence and authority are organized in Latin America.\n"]