Are Politicians Responsive to Mass Shootings? Evidence from U.S. State Legislatures

The United States leads the world in the number of mass shootings that occur each year even as policy making on firearms remains polarized along party lines. Are legislators responsive to mass shootings? We estimate the latent positions of 264 California state legislators on gun policy from their roll-call voting records on firearm-related bills from 2011 to 2022. Employing a stacked difference-in-differences design, we find that mass shootings within or near a state legislator's district do not alter their voting behavior on firearm policy, on average (with 95% confidence intervals spanning opposite directions). When we extend our analyses to an additional 5 states (for a total of 1,864 legislators), we find similarly null results, though we report evidence of statistically significant effects in both directions from event-specific estimates. Our findings suggest that even the most heinous acts of mass violence generally fail to produce measurable effects on legislators' positions on firearm-related policy.