The second trend is a continuing decline in violent and gun-related crime, including murder. Newly released FBI statistics show that 8,855 murders were committed using firearms in 2012 compared with 9,528 in 2008. During the same five-year period, overall murders dropped from 14,224 in 2008 to 12,765 in 2012. Over the past decade, “serious violent crime” (rape, sexual assault, robbery, and aggravated assault) with weapons declined by 26 percent. Such declines are of a piece with longer-term declines in violent crime rates. In 1993, for instance, the violent crime rate per 100,000 people was 747. In 2003, it was 476, and in 2012 it was 387.

Yet even if the continuing decline in violence in America means that new federal gun control legislation is a nonstarter, as House Minority Whip Rep. Steny Hoyer (D-MD) concedes, it doesn’t mean that the government is without the means of increasing worker safety at military installations.

As my Reason colleague J.D. Tuccille has pointed out, the Navy Yard falls under the restrictive rules and regulations that cover most military bases and effectively strip personnel of weapons. To work at the Navy Yard—even as a subcontractor, as Aaron Alexis was—required a security clearance. Precisely how Alexis, who received a general (as opposed to an honorable) discharge from the Navy and had a history of gun-related violence and mental instability, was able to pass any level of scrutiny and be allowed to work at the Navy Yard remains a mystery. Just six weeks ago, reports Fox News, a Rhode Island police officer reported Alexis to naval station police for erratic and delusional behavior.