Why have new firearms restrictions been so difficult to pass in the United States? One answer, suggested by a new study, is that gun-rights advocates may be more likely to snap into political action after a mass shooting.

In a study published in the June issue of Social Science Quarterly,  Kristin Goss, a researcher at Duke University,  analyzed the results of Pew Research Center surveys administered in the six months following the 2012 mass shooting at Sandy Hook Elementary School. She found that pro-gun men were significantly more likely to engage in political activism than any other group, dwarfing the efforts of individuals in favor of increased regulation, regardless of gender.

The examination is limited to the aftermath of Sandy Hook, which happened nearly five years ago. In the years since, the gun-violence-prevention movement has made significant strides in raising money and organizing volunteers. A similar evaluation conducted today might yield different results.

That said, Goss’s study goes a long way toward explaining the reluctance of public officials to adopt more restrictive gun laws. “Pro-gun organizations have a really, really well-developed infrastructure that’s been in place for a really long time,” Goss wrote in an email to The Trace. “[They have] strong bonds of social capital, and long experience with political mobilization.”

Pew asked random samples of Americans whether they had contacted a public official to express their opinion about gun policy; contributed money to an organization that takes a position on gun policy; expressed their opinion on gun policy using Facebook, Twitter, or another social network; or signed a petition about gun policy, in the six months after Sandy Hook.  

The results show that pro-gun men were the most politically active group relative to their population, comprising only 27 percent of the sample but 28 to 37 percent of political acts.

Pro-regulation women, the largest segment of the sample, consistently underperformed relative to their population.

While pro-gun men were more politically active across the board, a breakdown of the study’s data shows that on one issue pro-regulation women won out: background checks.

All in all, the pro-gun advantage in terms of activism stood between 9 and 19 percentage points for both genders combined.

It’s worth noting that gun-rights groups benefit directly from this boost in political participation. The National Rifle Association experienced a surge in membership and a sudden influx of cash following Sandy Hook — a pattern that often repeats itself with the new threat of gun restrictions.