This report analyzes the reported killing of CJNG leader Nemesio Rubén Oseguera Cervantes (“El Mencho”) and the immediate nationwide retaliatory violence that followed. It assesses the operational, economic, and national security implications for Mexico, examines potential succession and fragmentation risks within CJNG, and evaluates the broader impact on U.S. interests, Foreign Terrorist Organization designation dynamics, and security planning for high-visibility events such as the 2026 FIFA World Cup