“Is it possible that like we saw in 2016, we could see him come on strong in the last week and maybe not win the popular vote, but the electoral vote?” asked Valliere, adding that Trump also faces large deficits in advertising and funding in the latter stages of the campaign compared with Biden—something the president did not face in 2016.

But a few things might make the difference for Trump. Valliere says the White House has been holding out hope that a Biden gaffe, perhaps comments about the future of oil and fossil fuels, could boost Trump’s chances in states like Pennsylvania and Texas.

Valliere also expressed concerns about Biden’s “frailty.”

“I’ve known him for 40 years; he’s maybe lost a mile off of his fastball,” said Valliere. “He sometimes can’t find the right words. I think that’s a factor as well.”

Valliere dismissed the idea that a story about Hunter Biden’s questionable business dealings could become an October surprise that might turn an election, but he also said that more controversy could be unearthed before election day that’s harmful to either Biden or the president.

Pollsters have improved their methodologies since 2016, said Valliere, reducing the chance that they could be wrong.

“Many feel that polls don’t accurately capture Trump supporters, but poll takers feel like they have better methodology now capturing a better mix of rich and poor, black and white, young and old, male and female. They’ll still tell you they have a hard time figuring out turnout. If it’s a cold and rainy day in Columbus, Ohio, on election day, maybe the turnout for Biden wouldn’t be so great, but turnout for Trump’s supporters would probably be great even in a hurricane.”

Rather than believing any one poll (he doesn’t), Valliere recommends that those curious about the potential trends and outcomes in the elections look at aggregates of polls, like those on Realclearpolitics.com, which he is a big fan of.

By looking at changes in certain polls over time, they can be useful in capturing trends in the electorate’s sentiment, said Valliere, who has traced a pattern through 2020 where Biden performed strongly throughout the summer, then faded as the race tightened through early autumn.

He points out that Biden is running more strongly with key demographics in 2020 than Hillary Clinton did in 2016.

“Biden’s numbers among females are better than Hillary Clinton’s,” he said. “Biden has a 25 percentage-point advantage over Trump among female voters in some areas, which is kind of a surprise. An awful lot of senior citizens, who Trump carried four years ago, are saying they don’t like the way he handled the virus. It’s not a surprise now that it’s very close in Arizona and Florida, two states filled with retirees.”

Early voting numbers also seem to favor Biden, said Valliere, with 61 million Americans having already cast their ballots as of Tuesday. He believes most of the people standing in lines to vote are Democrats—but that Republicans could make up a lot of ground on election day.

But Republicans’ ability to gain ground between now and Tuesday is limited, he said, as at least “94% to 95% of the public have already made up their minds.”

The other big wild card is the pandemic, he said.