The Paradox of Accountability: Incumbent Insulation and Challenger Punishment in the Aftermath of Mass Shootings

This paper investigates how a uniquely American tragedy—the mass shooting—impacts electoral accountability in local politics. We examine whether voters punish or reward incumbent mayors for these events and how the electoral fortunes of challengers are affected. We employ a quasi-experimental event study design using a two-way fixed-effects regression model on a comprehensive dataset of U.S. mayoral elections. This approach allows us to isolate the causal effect of a mass shooting on candidate vote share and win probability while controlling for time-invariant city characteristics and national trends. Our findings reveal a stark paradox of accountability. A mass shooting precipitates a substantial and durable electoral penalty for non-incumbent candidates, reducing their vote share by approximately 10 percentage points. Conversely, incumbent mayors are completely insulated from this blame; the electoral effect for them is statistically indistinguishable from zero. We find no evidence that these events affect broader electoral dynamics such as voter turnout or candidate entry. These results challenge standard models of retrospective voting. They suggest that in the face of community trauma, voters engage in a form of "biased attentiveness," shielding the incumbent as a symbol of stability while punishing challengers who are perceived as introducing political conflict. This dynamic insulates leaders from accountability, reinforces the status quo, and raises critical questions about the functioning of democratic accountability in an age of crisis. [This version is a Preprint.]