There is some evidence, though, that Trump’s illness may be hurting his reelection chances. SurveyUSA was in the field with a national poll from Oct. 1 (before Trump announced his diagnosis) to Oct. 4 (when Trump was in the hospital), and the pollster found that Joe Biden led Trump by just 4 points in interviews conducted before Trump was hospitalized. But in interviews after Trump’s hospitalization, Biden led by 16 points. A Franklin Pierce University/Boston Herald poll identified a similar pattern: Biden led by 5 points in interviews conducted before Trump’s diagnosis and by a shocking 21 points in interviews after it.
But not every poll showed this shift. Monmouth University, one of the best pollsters in the business, was also in the field with a Pennsylvania survey late last week, and it found that the horse race largely did not change after Trump’s diagnosis. Biden led by 12 points in interviews on Sept. 30 and Oct. 1 and by 13 points in interviews from Oct. 2 to Oct. 4. Civiqs/Daily Kos, polling just after Trump’s diagnosis, asked a detailed question about how “anything in the news or in [their] daily life” might affect people’s votes, but they found that essentially no one was changing their minds.
In addition, Skelley and Thomson-DeVeaux talked to multiple political scientists who said that attitudes on the coronavirus have hardened over the past several months, especially along party lines, so a big shift in public opinion is unlikely.