VIRGINIA ONCE held the dubious distinction of being the top supplier of weapons to gunrunners in the Northeast. In 1991, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) concluded that 40 percent of some 1,200 handguns collected from New York crime scenes had come from Virginia. Guns from the commonwealth were also routinely recovered from crime scenes in the District. One reason for the allure of Virginia’s weaponry: a state law that allowed unlimited purchases of handguns.

That trend reversed after Virginia enacted a one-gun-a-month limit on purchases to address the gunrunning problem in 1993. In 1995, a pro-gun lawmaker gave the Virginia State Crime Commission the task of studying the limit’s impact. The commission found that the law had significantly reduced the number of Virginia guns found at crime scenes beyond its borders. A contemporaneous study by the Center to Prevent Handgun Violence (now known as the Brady Center) showed that the limit reduced by 66 percent the number of Virginia-bought guns recovered from crimes scenes in the Northeast corridor. The authors of the study, which was published in the Journal of the American Medical Association, concluded that it “provides evidence that restricting handgun purchases to 1 per month is an effective means of disrupting the illegal interstate transfer of firearms.” Rounding things out, the ATF knocked Virginia off the top of the list of leading exporter of crime guns; Georgia claimed the top spot.

The law worked, which is why it is unfathomable that the state is on the verge of throwing it out. Both chambers of the legislature approved eliminating the one-gun-a-month limit last week. The only thing standing in the way of the bill becoming law is the signature of Gov. Robert F. McDonnell (R), who voted for the limit as a state delegate but has since reversed course.

Virginia advocates of repeal argue that limiting law-abiding state residents to one purchase per month spits in the face of their Second Amendment rights. Does the Second Amendment guarantee a right to purchase dozens, hundreds, maybe thousands of deadly weapons each month? Even with the one-gun-a-month limit, collectors and those who could show a need for additional guns for personal or business protection were permitted to petition the state for an exception; the vast majority of these requests were approved.

To discard a law that has been effective for almost 20 years makes no sense.