The data keep rolling in that Biden is flipping a pattern from 2016 that really hurt Clinton. In that election,those voters that didn't like either candidate voted lopsidedly for Trump. This year, as David Siders notes in a useful article on Politico, it's the reverse: voters who don't like either candidate say they'll vote for Biden by a wide margin. I checked this pattern on the Nationscape data (85,000+ cases since the beginning of the year) and find strong confirmation: voters unfavorable to both candidates prefer Biden by 35 points (55-20).
From the Siders article:
"Unlike in 2016, when a large group of voters who disliked both Trump and Hillary Clinton broke sharply for Trump, the opposite is happening now, according to public polling and private surveys conducted by Republicans and Democrats alike.
It's a significant and often underappreciated group of voters. Of the nearly 20 percent of voters who disliked both Clinton and Trump in 2016, Trump outperformed Clinton by about 17 percentage points, according to exit polls.
Four years later, that same group — including a mix of Bernie Sanders supporters, other Democrats, disaffected Republicans and independents — strongly prefers Biden, the polling shows. The former vice president leads Trump by more than 40 percentage points among that group, which accounts for nearly a quarter of registered voters, according to a Monmouth University poll last week.
“It’s a huge difference,” said Patrick Murray, who oversees the Monmouth poll. “That’s a group that if you don’t like either one of them, you will vote against the status quo. And in the 2016 election, Hillary Clinton represented more of the status quo than Trump did. In this current election, the status quo is Donald Trump.”