In Colorado and Washington state, advocates spent millions of dollars, and two Colorado Democrats lost their seats, in the effort to pass laws requiring criminal background checks on every single gun sale.

More than three years later, researchers have concluded that the new laws had little measurable effect, probably because citizens simply decided not to comply and there was a lack of enforcement by authorities.

The results of the new study, conducted by some of America’s most well-respected gun violence researchers, is a setback for a growing gun control movement that has centered its national strategy on precisely the kind of state laws passed in Colorado and Washington. A third, smaller state, Delaware, passed a background check law around the same time and did see increases in the number of background checks conducted, the study found. But a similar background-check law in Nevada passed in 2016 has also run into political hurdles and has never been enforced.

“These aren’t the results I hoped to see. I hoped to see an effect. But it’s much more important to see what’s actually happened,” said Garen Wintemute, one of the study’s authors. Wintemute is a University of California Davis emergency room physician and has been conducting public health research on gun violence for decades, sometimes self-funding his research when federal funding dried up.

“We know background check laws work, and this latest research shows Delaware in particular has seen a dramatic impact,” said Sarah Tofte, research director at Everytown for Gun Safety. “This research also shows how critical implementation and enforcement are, and it suggests Colorado and Washington still have gaps in those areas that can and should be addressed.”

In most states, Americans are allowed to sell their guns to each other privately without conducting a background check. In contrast, licensed gun dealers are required to consult a national database that lists people who are disqualified from owning a gun because of a criminal record or other disqualifying record.

Congressional Republicans, joined by a handful of Democrats, have repeatedly refused to pass a national law to require background checks on gun sales, despite public survey results that show overwhelming public support for the policy. As a result, some states have chosen to close the loophole themselves, mandating that any gun sale now be preceded by a background check, an attempt to crack down on the flow of guns to the illegal market.

Opponents of the new laws in both Colorado and Washington had proudly advertised their noncompliance with the new regulations. In Washington, Wintemute and his co-authors noted, more than 1,000 gun rights supporters held an “I will not comply” demonstration at the state capitol where they reportedly flouted the newly passed law in public by transferring firearms to each other in full view of law enforcement. In Colorado, some sheriffs in more conservative rural areas reportedly said they would not enforce the new gun control law, and others that enforcement would simply be “a very low priority”.

The new research results are likely to be touted by opponents of gun control as evidence that new gun regulations are futile. The National Rifle Association did not immediately respond to a request for comment.

Under American law, only a few categories of people, including convicted felons, are barred from gun ownership. America’s relatively permissive gun laws, together with the estimated 300m civilian-owned guns, make it more difficult to keep guns out of the hands of people who are not legally allowed to have them. Despite this challenge, some gun control laws, including laws aimed at disarming domestic abusers, have shown success in reducing gun murders.

“Passing these laws is just part of the battle, and making sure they work effectively once they’re passed is very, very important,” said Josh Horwitz, the executive director of the Coalition to Stop Gun Violence. He cautioned that looking at a law a few years after it’s passed is still very early in the process. “It really takes time for the system to coalesce around the new law, and that’s because people have done things one way for a long time.”



After advocates in Washington state worked together with law enforcement officials, prosecutors and judges to sit down together and figure out how to best enforce a new domestic violence gun law, compliance with the law increased, Horwitz said.

But the need to focus on enforcing new gun laws, as well as simply passing them, adds another layer of work for a gun violence prevention movement that is still relatively small, and that faces battles across the country to pass new gun control laws and to fight against efforts to erase existing gun restrictions.



“Our influence has grown exponentially over the past five years,” said Peter Ambler, the executive director of Americans for Responsible Solutions, a newer gun control group founded by the former US congresswoman Gabrielle Giffords, who survived a mass shooting in 2011. “But if you look at our funding compared to how we as a society otherwise address causes of mortality and injury that are similar in scope – or if you look at our opposition in the NRA – we still don’t have comprehensive resources for the problem at hand.”

The conclusion readers draw from the new study should not be that the background policy is “no good”, Wintemute said. “It’s evidence that these policies may need more assertive enforcement.”

“If I’m an advocate pushing for one of these laws, [I would ask]: ‘What can I do to maximize the opportunities for enforcement? Does that mean funding for law enforcement, for augmenting the activities of an enforcement unit?”

Another approach, Wintemute said, would be focusing on education, “to assertively remind private party sellers that background checks on their buyers is required, and that not having that background check done is a crime, and it potentially exposes them to a much more serious risk if a crime is committed with that gun”.

The fact that private gun sales have long been totally unregulated and undocumented – the very reason that the new laws were passed – does make enforcement difficult, he said.

The new research also raises the question of whether gun violence prevention advocates would save more lives if they chose to fight for a slightly tougher law, which requires background checks to be conducted by a law enforcement agency which then provides a permit to purchase a gun. Research evaluations of these “permit to purchase” laws in Missouri and Connecticut found much stronger results in preventing gun murders than the evaluation of universal background check laws alone found.

The new study, published in Injury Prevention, a medical journal, did not attempt to analyze whether the new background check laws in Delaware, Colorado and Washington had any effect on gun violence or gun crime. Instead, it asked a simpler question: did a law requiring more background checks actually result in more background checks being conducted?

In Delaware, a small state on the liberal east coast, the answer was yes. Delaware saw a 25% increase in background checks for handguns and a 34% increase in background checks for long guns, the study found.

In Colorado and Washington, both western states that have large rural, more conservative areas, the answer was no. Both states showed modest increases in the number of background checks conducted on certain kinds of private gun sales, according to other data sets, showing that some people did appear to be complying with the new laws. But neither state saw an increase in the number of overall background checks compared with the number researchers would have expected to see without the law.