But Guy Cecil, the PAC's chairman, struck a cautious tone during a briefing on Friday, telling reporters: "While we have seen some improvement in the overall numbers over the course of the last month, we continue to have a structurally stable and relatively close race."
"Relatively small changes" could still make a difference in the Electoral College outcome, he added.
Several national polls have recently shown Biden, the former vice-president, ahead by double digits, while an Financial Times analysis of RealClearPolitics data puts his lead at nine points. In several battleground states that hold the key to winning the Electoral College, he is also in the lead, albeit by a smaller margin.
An FT analysis of recent state polls gives Biden an almost seven-point advantage in both Michigan and Pennsylvania, and a six-point edge in Wisconsin — three Midwestern states that were crucial in Trump's come-from-behind victory in 2016.
Larry Sabato, director of the University of Virginia's Center for Politics, said that the intensely polarised nature of US politics meant it was "hard to imagine" a Biden landslide akin to 1984, when Republican Ronald Reagan carried 49 out of 50 states and 60 per cent of the popular vote.
But he added that the president "appears to be doing everything he can to create" such an outcome, pointing to Trump's decision late last week to pull out of the second presidential debate.
"That was an opportunity for him to move up," Sabato said. "He is the one who is behind. Even his own people privately admit he is behind, and not by a little bit. They are very worried about it."
Frank Luntz, a veteran Republican pollster, said he did not understand Trump's demand for the two remaining debates to be held closer to polling day given how many Americans are planning to vote early.
"Donald Trump is too far behind to close the gap if he doesn't do two debates," he said. "There is no low-hanging fruit any more. There is no one who has not made at least an initial decision of who they lean towards. The longer that he goes, the more difficult it becomes. In fact, the more impossible it becomes."
Amid concerns about the health risks of voting in person on election day during the pandemic, at least 9.1 million Americans have already voted, according to the US Elections Project, a database compiled by Michael McDonald, a professor at the University of Florida.
"You can't look at the polling and not be worried that it is going to be a difficult month," said Luke Thompson, a Republican strategist.
But Thompson argued the president still had a path to victory, if the news cycle moved on from his own illness and if the state polls were systematically undercounting Republicans.
The Trump campaign has repeatedly said that polls are not weighted enough to account for the number of Republicans likely to vote. While Democrats maintain an edge on Republicans in terms of the number of registered voters in several key swing states, the GOP has closed the gap in places such as Pennsylvania and Florida.
However, the argument does not concern most Democrats, particularly the small number who are willing to say out loud that they expect Biden to win comfortably in November.
"I think this has the potential to end up, if not a landslide by 1984 proportions, then a big victory, and much bigger than we are used to in the last 20 years," said Matt Bennett, co-founder of the Democratic think-tank Third Way.
"People are not likely to go and say, I am going to roll the dice and take a chance on this guy who has been president for four years," he added. "They know what they think about Trump. He is not going to change a lot of minds between now and November 3."
Written by: Lauren Fedor and Brooke Fox
© Financial Times
