Twenty-two Democratic senators and one independent sent a letter to Senate Majority Leader Mitch McConnell and Minority Leader Harry Reid Wednesday seeking to keep a rider that blocks federal research into gun violence out of annual appropriations bills. In light of the “gun epidemic,” the letter states:

One step that we should be able to agree on is to study the problem, in order to understand the causes and characteristics of gun violence and the best strategies to prevent future tragedies. Yet policymakers, healthcare practitioners, researchers, and others lack comprehensive, scientific information because gun-violence prevention research has ground to a halt. The principal reason is that, since 1996, Congress included an annual appropriations rider prohibiting the Centers for Disease Control and Prevention (CDC) from lobbying for gun control. Specifically, the rider provides that none of the funds available to the CDC may be used “to advocate or promote gun control.” Unfortunately, this rider has been misconstrued as a ban on supporting scientific research into the causes of gun violence and has chilled practically all research efforts.

The research “ban” is one of the most pernicious impacts of the extremists in charge of the National Rifle Association. NRA arm-twisting led to the rider the senators talk about in the letter being passed in 1996. It was first added to an appropriations bill by Jay Dickey Jr., then a Republican Congressman from Arkansas. Congress followed up by shifting $2.6 million that the previous year had been budgeted for gun violence research into traumatic brain injury research, instead.

After that first vote, Knight-Ridder investigated and found that 75 percent of the lawmakers who backed the Dickey Amendment had received $1.6 million from the NRA that same year. Only six of the 158 members who opposed the measure had received support from the gun lobby.

The NRA’s motives were clear. In 1993, in the New England Journal of Medicine, Arthur Kellerman, and his colleagues published “Gun ownership as a risk factor for homicide in the home.” The study showed that rather than protecting families, keeping guns at home was associated with an increased risk of homicide by a family member or intimate acquaintance. The NRA demanded elimination of the CDC’s National Center for Injury Prevention and Control, which had funded the NEJM study.

The Dickey Amendment didn’t actually prohibit all federally funded gun violence research. But, as Michael Hiltzik has reported, “The real blow was delivered by a succession of pusillanimous CDC directors, who decided that the safest course bureaucratically was simply to zero out the whole field.”