“With U.S. backing, Mexico has gone to battle against the cartels, jailing drug users and drug runners, destroying opium and marijuana fields and sending thousands of armed soldiers into the streets. That may have weakened cartels, but it has opened the door for bloody infighting among splintered factions. Last year was Mexico’s most violent on record since the government began releasing crime statistics two decades ago, with 25,316 homicide investigations into 31,174 deaths.”