In this chapter, we develop a comprehensive model where we include assessments of each campaign event (e.g., September debate) and issue (e.g., election integrity, worries about COVID-19) when predicting overall evaluations of Biden and Trump in November as well as changes in feeling thermometer scores from September to November. These models show that views about the first presidential debate and attitudes toward major campaign issues (i.e., election integrity, COVID-19, social justice protests) explain views of the candidates in November and predict shifts in evaluations over the length of the campaign. Finally, we estimate changes in vote preference from September to November and we find that elements of the campaign (e.g., views about the presidential debate, support for social justice protests) produce important changes in vote preferences. In other words, we find strong evidence that the 2020 campaign mattered.