Mr. Trump didn’t just lose support to the undecided column; Mr. Biden ticked up to an average of 37 percent among white voters without a degree. The figure would be enough to assure Mr. Biden the presidency, given his considerable strength among white college graduates. In the most recent polls, white college graduates back Mr. Biden by a 20-point margin, up four points since the spring. It’s also an eight-point improvement for the Democratic nominee since 2016, and a 26-point improvement since 2012.
Mr. Biden has also made some progress toward redressing his weakness among younger voters. Voters ages 18 to 34 now back Mr. Biden by a 22-point margin, up six points from the spring and now somewhat ahead of Hillary Clinton’s lead in the final polls of 2016. Young voters will probably never be a strength for Mr. Biden — a septuagenarian who promised a return to normal, rather than fundamental change during the Democratic primary — but for now his margin is not so small as to constitute a grave threat to his prospects.
Remarkably, Mr. Biden still leads by seven points among voters 65 and over in the most recent surveys, despite the kind of racial unrest that led many of these voters to support Republican candidates at various points in their lifetimes. It should be noted that Mr. Biden’s lead among older voters is somewhat narrower than it was a few months ago, either reflecting the statistical noise of small sample sizes or reflecting the toll of recent events. Yet it is still a commanding strength for Mr. Biden compared with Mrs. Clinton’s five-point deficit among this group four years ago.
Perhaps more surprising in light of recent events is that Mr. Biden has not made substantial gains with nonwhite voters. He leads among them by 46 points in the most recent polls, up a mere percentage point from the polls conducted in March and April. It’s still behind the 50-point margin held by Mrs. Clinton in the final weeks of the 2016 race. Most pollsters do not break out nonwhite voters in much depth because of the small sample size, making it hard to explore the precise sources of Mr. Biden’s relative weakness. But for now, it seems reasonable to assume that his struggles are most acute among young nonwhite voters and nonwhite men, given the overall national figures.
Of course, five months remain until the presidential election. There is plenty of time for the race to swing in Mr. Trump’s favor, just as it did in the final stretch of the 2016 campaign. Indeed, the 2016 race was characterized by a predictable, mean-reverting oscillation between nearly double-digit leads for Mrs. Clinton — as in August and October — and a tighter race in which Mr. Trump trailed in national polls but remained highly competitive — as in July, September and November.
Mr. Biden’s lead in the polls today is not vastly different from the leads Mrs. Clinton claimed at her peaks after the “Access Hollywood” tape was revealed or when Mr. Trump became embroiled in a feud with a Muslim Gold Star military family.
There are reasons to doubt that the polling this year will again take on the character of a slow-motion, sine-wave roller-coaster ride. Many of the swings toward Mr. Trump were driven at least in part by news and negative coverage about Mrs. Clinton’s emails or her health. Joe Biden’s stay-at-home campaign tends to keep the spotlight focused on Mr. Trump. The Trump campaign has not resolved on a central attack on Mr. Biden. Perhaps as a result, Mr. Trump’s high points in national polls have never been as high as they were in 2016.