Monday’s horrific mass shooting at the Washington, D.C. Navy Yard left 12 victims (plus the shooter) dead and more than a dozen people wounded. It has raised immediate, impassioned, and understandable—if ultimately misguided—calls for increased levels of gun control now.

Sen. Dianne Feinstein (D-CA), a longtime proponent of assault-weapons bans whose effectiveness is questionable at best, announced that the killer was armed with a “military-style assault weapon” and asked, “When will enough be enough?” She argued for restricting sales of AR-15 rifles even though the shooter was not armed with that weapon.

Joining Feinstein in specifically denouncing the AR-15 was CNN host Piers Morgan, who said on his show that the Navy Yard installation had been “infiltrated by a man with a legally purchased AR-15, who just committed the same kind of atrocity as we saw at Sandy Hook and Aurora.” After learning that Aaron Alexis had in fact been unable to purchase such a weapon due to existing laws, Morgan tweeted, “Lots of confusion over exactly what guns Wash Navy Yard shooter used. But do you think it matters to the victims? #GunControlNow”

Feinstein’s and Morgan’s imprecise reactions suggest exactly why legislation shouldn’t be crafted, much less passed, in the heat of a crisis. Whether it’s truly awful drug laws pushed in the wake of high-profile celebrity deaths, national-security measures rushed unread through Congress after the 9/11 attacks, or transformative bailouts to the banking and auto industries essentially cobbled together over a long weekend, laws should be the product of serious and dispassionate deliberation. We feel with our hearts, yes, but we should govern with our minds.

Any calls for new gun legislation need to be squared with two long-term trends that are directly relevant to the unspeakable crime at the Navy Yard. The first is that mass shootings are not increasing. Northeastern University’s James Alan Fox, co-author of the 2011 book Extreme Killing, defines mass killings as those in which four or more people die and says there is no increase in such events in recent years. As he told Bloomberg, “Our tendency is to go overboard and overreach in terms of trying to increase levels of security … [but] this is not an epidemic.”

In the wake of the December 2012 Sandy Hook shooting, Mother Jones published a widely cited tally suggesting that mass shootings were in fact trending upward. In an article for The Boston Globe, Fox criticizes Mother Jones for “exclud[ing] cases based on motive, location, and victim-offender relationship.” Despite shootings in Aurora, Colorado, and Connecticut, “there has been no upward trend in mass shootings” wrote Fox, who provides an illuminating chart of incidents and casualties covering the years from 1976 to 2010. “What is abundantly clear from the full array of mass shootings, besides the lack of any trend upward or downward, is the largely random variability in the annual counts.”

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.

The Pentagon is reportedly auditing its security-clearance processes for military installations; one assumes other workplaces will follow suit. Such attention comes too late to offer any succor or comfort to the families, friends, and co-workers mourning the dead. But in the end, it is far more likely to be effective than any sort of gun-control legislation urged after a mass shooting.