Violence erupted after the 1989 arrest of Miguel Ángel Félix Gallardo, who was the leader and founder of Mexico’s first major drug cartel, the Guadalajara Cartel. His arrest led to the dissolution of the cartel as high-ranking members splintered off to create their own groups. This fragmentation gave rise to the Sinaloa, Juarez, Tijuana, and Sonora cartels, among others, which began to battle for control over lucrative trafficking routes and territories. This marked a new chapter in the drug war, with the cartels becoming increasingly violent in their efforts to secure dominance.
Mexican drug trafficking organizations have been a powerful force for decades, but their power surged significantly in the 1990s after the collapse of the Colombian Cali and Medellín cartels. By 2007, Mexican criminal groups controlled an overwhelming 90% of the cocaine entering the United States. Efforts to arrest cartel leaders, including those in the Tijuana and Gulf cartels, often resulted in even more violence, as smaller gangs competed for control over key drug trade routes into the U.S.