Until the 1980s, Mexico enjoyed relative freedom from violence. Ruthless drug cartels existed, but they usually abided by informal rules of conduct hammered out between several capos and representatives of the dominant Institutional Revolutionary Party (PRI), which ruled the country until the 1990s. Relying on bribes, the desperados pursued their illicit activities with the connivance of authorities In return for the legal authorities turning a blind eye, drug dealers behaved discretely, shunned...