Partisan responsiveness in real time: causal evidence from Trump’s military attack on Iran

Abstract Elite cues signal citizens how to interpret political events through a partisan lens. Do these effects occur in real time? We exploit President Trump’s unexpected announcement of US military strikes against Iran during a nationally representative survey to estimate the causal effect of elite cues on public opinion. Leveraging minute-level variation in exposure, we find that partisan divergence emerges almost immediately: support for military intervention increases among Republicans but declines among Democrats. These large effects remain robust across 28,672 model specifications and 57,344 partisan-specific treatment effects. Our quasi-experimental evidence demonstrates that elite cues can polarize public opinion within minutes, even before media framing and partisan commentary have diffused, highlighting the speed of partisan opinion formation and its implications for democratic accountability.