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

The United States leads the world in the number of violent mass shootings that occur each year, and policy making on firearms remains polarized along party lines. Are legislators responsive to mass shootings? We estimate the latent positions of nearly 2,000 state legislators on gun policy from their roll-call voting records on firearm-related bills from 2011 to 2022. Employing a staggered 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, for members of both parties. Our estimated effects of mass shootings on treated legislators' support for restrictive gun policies (on a -1 to 1 scale) range from a 4.8% reduction among California Democrats and a 0.9% increase among California Republicans to, across six total states, a 5% (among Democrats) and 7.1% (among Republicans) increase, with 95% confidence intervals spanning opposite directions. We conclude that, on average, mass shootings fail to produce changes in a legislator's support (opposition) for restrictive (permissive) firearms bills. Our findings suggest that even the most heinous acts of mass violence -- that are squarely in the domain of events that state legislators might respond to -- fail to produce any measurable effects on legislators' positions on firearm-related policy.