Drug-related violence over the weekend claimed 51 lives across Mexico, including 15 decapitations in the beach resort of Acapulco, authorities reported. The beheadings, mutilations, drive-by shootings and summary executions were carried out in southeastern Guerrero and northern Chihuahua states, as well as in the Mexican capital, despite the government’s five-year, 50,000-troop crackdown on...