OPINION — The only thing that stops a bad guy with a gun is a good guy with a gun. It’s the mantra of the National Rifle Association, and a certainty for those who would brook no incursion into Second Amendment rights and definitely no gun control measures, no matter how small or “sensible,” as they are often described by those who propose them.

When children were gunned down at Sandy Hook Elementary School in Newtown, Connecticut, in 2012, and federal legislation that would strengthen background checks went nowhere, gun control advocates despaired. If the murder of children failed to crack the gun lobby, what would?

But real-life events and political surprises indicate that the landscape might be changing. And the work of groups such as the Brady Campaign to Prevent Gun Violence, Moms Demand Action for Gun Sense in America, the Giffords Law Center to Prevent Gun Violence and other large and small organizations has made a difference.

Where once politicians were loath to cross the NRA because of the organization’s hefty purse and powerful get-out-the-vote success, candidates in unlikely places are showing that a nuanced position is not a deal breaker. Earlier this month, Democrat Lucy McBath, a onetime spokesperson for Moms Demand Action for Gun Sense, won a House seat in Georgia that Newt Gingrich once held, no doubt surprising some leaders in her own party. Though the district has been trending away from its once deep-red hue for a while, a well-financed race by Democrat Jon Ossoff last year that engendered enthusiasm could not achieve what McBath did with far less attention.

McBath, an African-American woman whose activism was motivated by the murder of her son, Jordan Davis, in 2012 by a white man angered by the volume of his music, expressed support for the Second Amendment as well as changes in gun laws, including closing background check loopholes. Her platform did not stop there, also featuring a variety of other issues of concern, including affordable health care and middle-class tax cuts. And McBath was not the only new member of Congress elected on a similar platform.