Joe Biden heads into convention with diminished but still sizable lead

A wave of new national surveys shows that Joe Biden maintains a significant if slightly diminished lead over Donald Trump, leaving him in a stronger position to oust an incumbent president than any challenger heading into his party’s convention in the modern polling era.

On average, Biden leads by eight to nine percentage points among likely voters. His advantage is perhaps slightly smaller than it was a month ago, when high-quality live-interview telephone surveys routinely showed him with a double-digit lead. But it is still the largest and most persistent national polling lead that any candidate has held in 24 years, since Bill Clinton maintained a double-digit advantage in 1996.

The conventions often introduce a volatile and uncertain period for public polling, as candidates usually gain in the polls after several days in the limelight on national television. Though it’s possible that the virtual nature of this year’s conventions will dampen that effect, this may be the last unbiased measurement of the state of the race until mid-September.

For now, the state of the race is clear, ending a nearly two-month period when live-interview and online polls showed a modestly different race. The new consensus can be attributed mainly to a shift among live-interview telephone surveys, which show a two-point shift in Trump’s direction. The online polls have remained largely unchanged.

The slight narrowing of Biden’s lead tracks with a similarly modest improvement in the president’s job approval rating. Overall, Trump’s approval rating among registered voters has increased to 42.2%, according to FiveThirtyEight, from its low of 40.3% on July 28.

This uptick may reflect a modestly more favorable national political environment. Protests and unrest have subsided. The growth of coronavirus cases has slowed. The more settled news environment appears to have allowed the president to claw back some of his likelier supporters. It may also reflect his campaign’s persistent effort to polarize the electorate and lure back some of his former supporters.

But Biden’s support hasn’t declined, even as his lead has shrunk somewhat. In fact, his share of the vote has increased. He now holds 51% of the vote in the polls, an unprecedented figure for a challenger heading into his party’s convention in the seven decades or so of modern polling. Trump has narrowed the gap with Biden by making even larger gains, but he has advanced to a mere 42 or 43% of the vote.

The lower number of undecided voters generally reduces the uncertainty about the overall state of the race.

Trump’s gains have been largest among white voters without a college degree, who now back him by 24 points, up from 18 points in live-interview polls weighted by education conducted in June or July. His strength among this group represents his only realistic path to victory, as it did in 2016. Yet he continues to underperform among these voters compared with the preelection polls from four years ago.

One area of relative if uncertain strength for Trump is among nonwhite voters. On average, the most recent polls show Biden with a 41-point lead among this group, his lowest of the cycle. This may be statistical noise, given the small sample of nonwhite voters in most national surveys.

But Biden has underperformed Hillary Clinton’s 2016 lead among registered nonwhite voters throughout this year, and it was notable that Biden made no gains at all among nonwhite voters in June and July, when the national political conversation was focused on issues with seemingly disproportionate resonance in Black and Hispanic communities, like criminal justice and policing.

A longer-term average of polling suggests that Trump’s relative strength among nonwhite voters is broad. He is faring better than he did four years ago among both Black and Hispanic voters.

The selection of Kamala Harris for vice president might offer at least some upside to Biden, though it is too soon to evaluate any effect she might have on the race. So far, there are no early signs that she has revitalized his standing among nonwhite voters. The only two telephone surveys conducted entirely after her selection, from CNN/SSRS and ABC News/Washington Post, show Biden faring somewhat worse among nonwhite voters than in their prior surveys from June or July.

We probably won’t have another clear sense of the overall state of the race until mid-September, after the two convention bounces have faded and the race briefly settles into a new normal before the debates.