Monday's horrific mass shooting at the D.C. Navy Yard left 12 victims dead and more than a dozen people wounded. It's raised impassioned, understandable – and ultimately misguided—calls for more gun control now. But legislation should almost never be crafted in the heat of a crisis.

Whether it's truly awful drug laws pushed in the wake of high-profile celebrity deaths or national-security measures rushed unread through Congress after the 9/11 attacks, legislation should be the product of serious and dispassionate deliberation.

The fact is that as Northeastern University's James Alan Fox has firmly established, there's no upward trend of mass shootings over the past 40 years. And when it comes to violent crime, the trend is clearly down. FBI statistics show the murders committed with firearms dropped between 2008 and 2012. Over the past decade rape, sexual assault, robbery, and aggravated assault committed with weapons declined by 26 percent. Overall violent crime rates are about half of what they were 20 years ago.

The Navy Yard gunman, Aaron Alexis, somehow managed to get a security clearance to work at a military installation as a sub-contractor despite getting booted from the Navy and a history of gun-related violence, mental instability, and erratic behavior.

The Pentagon is auditing its security-clearance and hiring processes its bases; one assumes that other public and private workplaces will follow suit. Of course, this comes too late to offer any comfort to the families, friends, and co-workers mourning the dead and wounded. But in the end, it is far more likely to be effective than any sort of gun-control legislation rushed through Congress.

Approx. 1:45 min. Written by Nick Gillespie, produced by Meredith Bragg.