The great city of St. Louis has a major problem with gun violence. Even as homicide rates have continued to decline elsewhere in the country, they have surged in St. Louis, which last year saw a 33 percent rise in killing, to 159 in a city of 318,000. (Note: this does not include the death of Michael Brown in Ferguson, which is in St. Louis County, a separate jurisdiction with 1 million people.) Criminologists point to all the usual reasons for the violence: a thriving drug trade, high unemployment among young men, and so on. But a New York Times article on Tuesday noted that St. Louis police are contending with a factor that their counterparts in many other high-crime cities are not: exceedingly lax gun laws.