By Eric Lichtblau, New York Times

WASHINGTON — With guns emerging as a major flash point in the presidential race and campaigns nationwide, gun-control advocates are spending tens of millions of dollars on a central message: Stronger firearms laws can reduce gun violence.

Although the National Rifle Association has long rejected that assertion, a growing body of evidence from academics, advocacy groups and others supports the link between gun restrictions and a reduction in violence.

The latest analysis comes out Wednesday from the Center for American Progress, a leading liberal group that supports toughened gun control. It concludes that gun fatalities in states with weaker laws are more than three times as high as in those states with tougher restrictions, including background checks or permits.

Gun control has traditionally been a radioactive political issue in America. But voters in four states with gun measures on the ballot — California, Maine, Nevada and Washington — appear likely to approve toughened restrictions next month, and the gun debate is playing out in dozens of congressional campaigns as well.

In the presidential race, the NRA has spent more than $20 million on advertisements backing Donald Trump, who has voiced his strong support for gun rights, while urging gun right supporters to rise up against his Democratic opponent, Hillary Clinton.

“Trump would appoint Supreme Court justices who respect the Constitution and would uphold an individual’s right to bear arms,” Jennifer Baker, a spokeswoman for the NRA’s lobbying arm, said. “Hillary Clinton would not.”

With Congress still deadlocked over imposing new firearms measures, gun-control advocates have turned increasingly to state ballot initiatives and legislative races — with a string of successes in the last few years.

“We feel really excited about what’s happened on the gun issue this cycle,” said Peter Ambler, the executive director for Americans for Responsible Solutions, a gun-control-advocacy group. “The politics have shifted in a rather tectonic way.”

At a time of rising homicide rates in some major cities, the authors of the new report from the Center for American Progress believe their findings should bolster those efforts to impose tougher restrictions.

The group used 10 gun-crime and violence indicators for each state, including homicides, suicides and accidental shootings, and weighed them against how restrictive a state’s gun laws are.

The findings indicated a “strong” correlation between stricter gun laws and lower rates of violence, said Chelsea Parsons, one of the report’s authors.

To Learn More:

An Analysis of Gun Violence in the United States and the Link to Weak Gun Laws (by Chelsea Parsons and Eugenio Weigend Vargas, Center for American Progress)

Support Grows Among Americans for Tougher Gun Laws (by Lisa Marie Pane and Ryan J. Foley, Associated Press)

Gun Murders in Missouri Increase after Easing of Gun Control Laws (by Noel Brinkerhoff and Steve Straehley, AllGov)

Large Numbers of Americans Think Existing Guns Laws are Stronger than They Really Are (by Noel Brinkerhoff, AllGov)

Americans’ Desire for Tougher Gun Laws Up 13% from a Year Ago (by Noel Brinkerhoff, AllGov)