Nobody really knows how Missouri got the nickname the "show me state," but what we do know is that under a new gun law passed last week, Missouri residents will be able to walk around openly showing their guns. And what we further know is that this law drops the concealed carry (CCW) age requirement from 21 to 19 and allows local school districts to grant CCW privileges to teachers whose job will be to protect everyone else in the school from all those bad guys carrying guns.

The intent of this new law obviously is to make Missourians more safe because lowering the CCW age to 19 will qualify more people to walk around armed and letting teachers bring concealed weapons into schools will also protect the children and other teachers when a bad guy with a gun comes into the school. In other words, the new law supports a favorite theory of the NRA which can be summed up as "more guns equals fewer guns." Oops, what we mean is more guns carried around by the "good guys" means fewer guns carried around by the "bad guys."

The last time Missouri made it easier for its citizens to arm themselves was in 2007 when the legislature abolished a law which required that people wishing to buy handguns first had to go to the police department and get a permit-to-purchase (PTP) in order to take possession of the gun. To show you how successful this measure was in helping good-guy Missourians use guns to protect themselves from bad-guy Missourians, the gun homicide rate over the next three years jumped by almost 25 percent, even though the non-gun homicide rate remained about the same.

Of all 50 states, only Louisiana currently has a higher gun homicide rate than Missouri, and while the overall violent crime rate in Missouri has declined by about 20 percent between 2007 and 2012, the homicide rate has remained remarkably stable and remarkably high, a testament no doubt to the legislature's uncanny ability to understand how making it easier for everyone to acquire handguns would lead to a safer and more secure place to live. Having seen the positive impact of easier handgun access on gun homicide rates, the legislature in its wisdom now believes that it will move the gospel of "good guys with guns protecting us from bad guys with guns" into the schools.

But what are the facts about the utility of using guns to protect kids (and teachers) in schools? Actually, the number of homicides that take place in schools each year has shown the same gradual decline over the last twenty years that has characterized violent crime rates in the United States as a whole. From 1994 to 2013, violent crime dropped roughly 50 percent, with most of the decline taking place prior to 2004. As for school homicides, according to a Justice Department study, they have dropped by about the same amount over the period 1992 to 2010, and serious victimizations, including robberies and assaults, have declined by as much as two-thirds.

Most of this decline in school criminality seems to have been the result of increased attention paid to people entering school buildings and increased surveillance within the buildings. By 2011, nearly 90 percent of all public schools had some kind of security measures to monitor access and the same percentage reported requiring visitor sign-ins. On the other hand, less than one-third of all schools had armed security patrolling on a full-time or part-time basis. And while I don't have specific numbers on school security in Missouri, I can tell you that the last school shooting in the 'show me' state occurred in 1993.

Do you think there was any connection between the passage of the new Missouri gun law and the racial strife in Ferguson after the shooting of Michael Brown? It's as good a theory as any about what really motivated legislators to let guns into schools, because there sure isn't any violence problem in Missouri schools that this law will solve.