Of course, making it much easier to obtain a gun as Missouri did in 2007 means that the state now has a significantly higher rate of people using guns to kill people, so there's that.
In the past decade, Missouri has been a natural experiment in what happens when a state relaxes its gun control laws. For decades, it had one of the nation’s strongest measures to keep guns from dangerous people: a requirement that all handgun buyers get a gun permit by undergoing a background check in person at a sheriff’s office.
But the legislature repealed that in 2007 and approved a flurry of other changes, including, last year, lowering the legal age to carry a concealed gun to 19. What has followed may help answer a central question of the gun control debate: Does allowing people to more easily obtain guns make society safer or more dangerous?
We now have a pretty clear and tragic answer in Missouri.
Research by Daniel Webster, the director of the Johns Hopkins Center for Gun Policy and Research, found that in the first six years after the state repealed the requirement for comprehensive background checks and purchase permits, the gun homicide rate was 16 percent higher than it was the six years before. During the same period, the national rate declined by 11 percent. After Professor Webster controlled for poverty and other factors that could influence the homicide rate, and took into account homicide rates in other states, the result was slightly higher, rising by 18 percent in Missouri.
Federal death data released this month for 2014 showed a continuation of the trend, he said. Before the repeal, from 1999 to 2006, Missouri’s gun homicide rate was 13.8 percent higher than the national rate. From 2008 to 2014, it was 47 percent higher. (The new data also showed that the national death rate from guns was equal to that from motor vehicle crashes for the first time since the government began systematically tracking it.)
Other measures suggested that criminals had easier access to guns after the permit law was repealed. Professor Webster analyzed data from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, and found that the share of guns that were linked to crimes soon after they were bought doubled in the state from 2006 to 2010. The portion of guns confiscated by the police in Missouri that had been originally bought in the state — ordinarily a very stable statistic — rose to 74 percent last year, from 56 percent before the law changed.
The firearms industry would like you to believe that this is a case where correlation has nothing to do with causation, but the statistics are difficult to reconcile otherwise.
Missouri made it much easier to get a gun. As a result, more people used them for their intended purpose. There's now several years of data backing this up...but remember, according to Republicans, science is all a lie, so why bother?