Trump and Biden each got small convention bounces but only Biden got more popular

I don’t want to overstate the bump Biden got relative to Trump, though: The increase in Biden’s favorables, much like Trump’s improvement in head-to-head polls, was small by historical standards. As former FiveThirtyEight writer Harry Enten found in 2016, candidates from Jimmy Carter in 1980 to Bill Clinton in 1992 to Al Gore in 2000 to George W. Bush in 2004 saw double-digit surges in their net favorability rating after the conventions, as measured by CBS News polling. That definitely didn’t happen this year…

But Biden still has the advantage in the polls that have asked about this. On average in these polls, since the conventions ended, 26 percent of Americans have said they view Biden very favorably, and 36 percent have said they view him very unfavorably (that’s -10 points on net). By contrast, Trump has an average “very favorable” rating of 29 percent and an average “very unfavorable” rating of 47 percent (-18 points on net).

That’s a much narrower gap than FiveThirtyEight contributor Michael Tesler found in late June, when Biden was at -3 points and Trump was at -23 points in that measure. But it still suggests that voters’ motivations to vote against Trump are higher than their motivations to vote against Biden. As Tesler argued earlier this summer, this could mean that Biden, not Trump, is the candidate with the enthusiasm edge in this election.