We never will know why a mentally unstable person chose Lafayette to try to restart his life. We never will know why, after a matter of days there, he decided to fire a handgun inside a movie theater. The only thing we do know is that Louisiana law permits private entities engaged in public commerce a latitude that fails to discourage these kinds of incidents.

Last month at Lafayette’s Grand 16 Theatre, when John “Rusty” Houser fired more than a dozen shots in the span of about a minute, killing two and injuring nine others before the last bullet presumably ended his own life, he was firing a weapon legally obtained in Alabama by his passing a federal background check to buy it last year — despite the fact that previously he had been denied a concealed-carry permit in Alabama due to violent past episodes. A couple of years later, he was evaluated for his mental health but apparently not involuntarily committed, which would have made him unable to pass a background check.

Unfortunately, state law may have contributed to this unfortunate event. The Grand Theatre chain has a company policy of allowing no weapons, including firearms by a holder of a concealed-carry permit; in fact, it was the only theater in Lafayette with such a restriction. Louisiana law allows private property owners or lessees discretion to forbid handguns where the law otherwise would permit them.

Mental illness does not connote stupidity. Houser had been to the theater before (or he could have checked the company website) and surely knew of the company policy. Indeed, his diary left in his motel room showed the attack to be premeditated and that he specifically chose that location after apparently ruling out other theaters. If a sick individual wanted the least resistance in carrying out his twisted plans — almost all of these shooters, when they spot the first possibility of return fire, either immediately surrender or take their own lives, as Houser did when he saw police approaching him — then a business that promised plenty of targets and banned guns on its premises would be like a red cape waved in front of a bull.

While some have argued the tragedy demands more gun control, such a view rests on ideology, not proper understanding of the issue. The background check in Houser’s case operated as might be expected, given its limits. But according to figures compiled by the U.S. Department of Justice, in 89 percent of the cases where a firearm is involved in a criminal act, the perpetrator used a gun obtained without a background check — either from a private party or illegally. Nothing short of draconian, freedom-threatening curtailment of Second Amendment rights can keep guns out of the hands of people determined to do harm.

Instead of focusing on some perhaps unattainable ideal of perfection for firearms background checks, maybe the best way to help prevent such mass shootings is to eliminate the exception in state law that allows most businesses the option to forbid concealed-carry permit holders from carrying these legal weapons on their premises. Over the past two decades, much research, such as that published by analysts associated with the Crime Prevention Research Center, corroborates the deterrent effect of concealed-carry laws concerning violent crime, despite widespread but inadequate attempts to debunk their results.

There’s no reason to subvert an effective anti-crime policy by making it discretionary. In places where the law already allows possessing a concealed-carry firearm by a permit holder, the Legislature should revoke the ability of these businesses to ban these guns. That would reduce the chances of another horrific multiple shooting.

Jeff Sadow is an associate professor of political science at LSU in Shreveport, where he teaches Louisiana politics. He is author of a blog about Louisiana politics (www.between-lines.com) and, when the Louisiana Legislature is in session, another about legislation (www.laleglog.com). His views do not necessarily express those of his employer.