So What If Tommy Guns Are Popular?

How unusual?

Photographer: George Frey/Getty Images

When a sharply divided Supreme Court created an individual right to bear arms seven years ago, it also made clear that the right would remain subject to "longstanding prohibitions." On Monday, the court confirmed that some newer prohibitions are allowed as well.

The court's deference -- it refused to review a lower-court decision upholding a local ban on assault weapons -- should surprise no one. Arms have always been regulated in the U.S.; that's why it's against the law for people to put missile silos in their backyards, and why people must demonstrate "justifiable need" to obtain a permit to carry a handgun in New Jersey. The constitutional question has always been where to draw the line.

The city of Highland Park, Illinois, drew it at semi-automatic rifles with large-capacity magazines, a ban that includes the popular AR-15 military-style rifle. In court papers, the city argues that its law is constitutional because the Supreme Court's 2008 District of Columbia v. Heller decision allows the prohibition of weapons that are "dangerous and unusual."

No one argues that these guns aren't dangerous. But the National Rifle Association, it its amicus brief, focuses on the second adjective: "This case should have turned on a simple premise," the NRA brief states. "Firearms that are commonly chosen by law-abiding citizens for lawful purposes cannot be banned." In effect, the NRA argues that if a gun is "hugely popular," then it cannot be "unusual," so therefore it must be constitutional.

The appeals court decision, written by Reagan appointee Frank Easterbrook, offers one rejoinder to this argument, pointing out that there was a time when the tommy gun was popular among Chicago gangsters. By the NRA's logic, machine guns could be featured for sale in the display windows of Michigan Avenue.

Another persuasive argument comes from the city of Highland Park, which notes that about one-quarter of the nation's population lives in places where "assault weapons" are banned. These include seven states, the District of Columbia, New York City and San Francisco. There is nothing terribly unusual about a desire to ban them.

Leaving aside the American tendency to constitutionalize every argument, there is a more practical concern: To what effect is this regulation? On that score, the case highlights, once again, the need for comprehensive research on gun violence. Yet the gun movement has successfully encouraged Congress to defund and discourage such research at every turn. Knowledge about the efficacy of gun regulation is limited by a self-imposed ignorance.

QuickTake Guns in America

"A ban on assault weapons won't eliminate gun violence in Highland Park but it may reduce the overall dangerousness of crime that does occur," the lower court's ruling states. For gun policy to advance beyond the current stalemate in Congress, that kind of declaration is not good enough. Data needs to take its proper place in this debate.

To contact the senior editor responsible for Bloomberg View’s editorials: David Shipley at davidshipley@bloomberg.net.