The 2024 presidential election campaigns were shaken by series of extraordinary events, among them Trump’s felony conviction , Biden’s disastrous debate performance, Trump’s attempted assassination, Harris’s replacement of Biden, and Harris’s superior performance her debate with Trump. To what extend did these events shift intended presidential votes? I address this question through analysis of data from more than 320 surveys taken over the course of the campaign that asked respondents how they intended to vote in the presidential election. I find that the shocks had statistically significant but, with one exception, very small substantive effects on the prospective major-party votes of the electorate as a whole. The shocks had a much stronger effect on support for the Democratic candidate than on support for Trump. They left partisans largely unmoved; independent voters were much more responsive and thus accounted for most of movement in overall aggregate preferences that followed each event.
Gary C. Jacobson (Wed,) studied this question.