It’s no secret this country is extraordinarily divided on the issue of gun rights, and common ground has been hard to come by. That’s why it’s heartening to see fact-based evidence of a law that has produced results in curbing gun deaths without infringing on the rights of lawful owners to purchase weapons.

A new and rigorous study by Harvard Business Research shows that states with gun-purchase waiting periods consistently show 17 percent fewer gun homicides than states without such laws, saving 750 lives a year nationwide. Researchers project that a nationwide waiting period could save another 900 lives annually.

The findings come from a rigorous analysis of 45 years of data on every change to state and local waiting periods between 1970 and 2014. The results, researchers said, confirmed “a large and robust effect of waiting periods on homicides.” Findings on suicides were less consistent, but showed between 7 percent and 11 percent fewer gun suicides than in states without waiting periods. That could save a substantial number of lives, given that about half the suicides in the U.S. are caused by firearms, according to the National Center for Health Statistics.

What exists now is a hodgepodge of state regulations. California requires 10 days for all firearms purchases. Minnesota has a weeklong waiting period on handguns and assault-style rifles unless the weapon is bought through a private sale or the buyer already has a permit.

A waiting period won’t prevent all gun deaths, but researchers found that gun deaths resulting from impulsive emotion can be reduced through such measures. “Visceral factors, such as anger or suicidal impulses, can spur people to inflict harm on others or themselves, but tend to be transitory states,” the study noted, with a cooling-off period of as few as 48 hours producing noticeable reductions in gun deaths. The study drew on another set of data: The four years in which the U.S. did have a nationwide waiting period, replaced in 1998 by the current system of instant background checks. Researchers found the same 17 percent drop. Background checks have their own merits, but some are done in minutes. Having both waiting periods and background checks makes more sense.

Gun owners may find a waiting period irksome, but it is a minor inconvenience weighed against lives saved. No one qualified to own a gun is denied one. The wait is, in most instances, not much more than for an Amazon delivery. Some states have exceptions for urgent situations, in which local law enforcement can authorize a bypass of the waiting period. That’s an important safeguard.

What’s remarkable about the Harvard study is that it exists at all. For 20 years a ban on federally funding research has suppressed reasonable, fact-based debate, allowing tribalistic hyperbole to dominate discussions. Guns kill tens of thousands annually in the U.S. and seriously injure thousands more. Yet this country is kept deliberately in the dark as to possible effective remedies.

Other experts agree with the Harvard findings. Christopher Herrmann, a professor at John Jay College of Criminal Justice in New York, said his 20 years of study — including years with the New York Police Department — have convinced him that waiting periods are effective, particularly for workplace violence and domestic violence. “The guy who got fired, goes out, buys a gun and kills his boss and himself — that’s the kind who needs a cooling-off period,” Herrmann said. For domestic violence, he said, ready access to a gun can turn an assault into a homicide. “It’s a violence-reduction technique,” he said. “You are minimizing the opportunity individuals have to kill themselves or others.”

Harvard is to be commended for expending its own resources to provide factual evidence for what works. What is needed now is for Congress to act on it. Restore a national waiting period. Make it applicable to every gun purchase, including private sales. Not one individual in the United States will lose their right to own a gun because of it.

The public strongly supports waiting periods. As Herrmann noted, “They are easy to understand, tangible and practical.” There may be no better start to breaking the paralysis in this country on gun issues than a reasonable, nationwide waiting period.

— Minneapolis Star Tribune, Oct. 20