Adding Fuel to the (Gun)Fire: How Politicians Polarize the Public Debate

Abstract

We show how politicians polarize policy-relevant public debates. Analyzing 4.75 million tweets about 57 mass shootings events (2016-2022) with two-way fixed effects and event studies methodologies, we show that the partisan and tribal content of tweets---our measure of online polarization---systematically increases after a politician first tweets about an event. Our detailed analysis of the timing of political interventions suggests that politicians do not intervene in response to specific characteristics of the debate or the event, nor to immediate changes in the debate. Interventions by other (not politicians) focal influencers do \textit{not} polarize the public debate. We show how the rhetorical supply of politicians explains the unique polarizing effect of political interventions.