Vice President Kamala Harris’ rise to the top of the Democratic ticket has generated momentum in the polls for the party, but some experts aren’t convinced by her new lead.

"If the polling errors are anywhere close to what they were in 2016 and 2020, then Trump is in the lead right now," Democrat strategist Julian Epstein told Fox News Digital.

The comments come as the Real Clear Politics polling average shows Harris with a slim 1.5 point lead over former President Trump nationally, a significant shift from the three-point lead Trump held over Biden the day before the president dropped out of the race.

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Trump at campaign rally in Montana

Former President Trump arrives to speak at a campaign rally in Bozeman, Montana, on Aug. 9. The poll found American adults think more highly of Trump's ability to handle the economy, compared to Harris. (AP/Rick Bowmer)

But the Harris lead is also a much smaller gap than Trump faced at the same time in 2016 and 2020, when the Republican nominee trailed former Secretary of State Hillary Clinton by 6 points and Biden by 7.1.

While Trump won in 2016 and failed to win re-election in 2020, the former president greatly outperformed his polling numbers in two close elections, a fact that is not lost on Democrats heading into the stretch run of 2024.

According to a report from Politico last week, recent polls conducted by Democratic firms that show Harris in the lead also contain warning signs, including leads for Trump in characteristics more likely to sway voters. Harris is also essentially tied with Trump across the battleground states, the polls show, meaning the vice president is underperforming her national numbers in states set to decide the election.

"It’s still a very tough race, and that feels consistent with everything we know," said Margie Omero, a partner at the Democratic polling firm GBAO Strategies, told Politico.

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former President Trump speaking at event in Las Vegas

Former President Trump speaks at a campaign event, Friday, Aug. 23, 2024, in Las Vegas. (AP Photo/Julia Nikhinson)

Democratic pollsters also fear the prospect of another polling error, even though several of the party’s top firms got together in an attempt to diagnose the problem after 2020.

"I spent a ton of time and analysis trying to dig into those problems. And I feel much better educated about those problems," Nick Gourevitch, a partner at Global Strategy Group who participated in the Democratic "polling autopsy," told Politico. "I don’t think there’s any pollster in America who can sit here and say… that they’re 100% sure that they fixed any issues in polling. I think that would be silly."

That reality is not lost on Democratic pollsters, who have urged caution despite Harris’ quick rise over the last several weeks.

"Every year, we’ve had different curveballs. This is a difficult industry," John Anzalone, the lead pollster on Biden’s 2020 campaign, told Politico. "Something’s gonna happen in 2024. You and I, right now, don’t know what that is."

Vice President Kamala Harris at podium speaking in Florida

Vice President Kamala Harris speaks during an event at the Prime Osborn Convention Center on May 1, 2024, in Jacksonville, Florida. (Joe Raedle/Getty Images)

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Meanwhile, Epstein sees several reasons for Democrats to worry, pointing out that Harris is still "underperforming in the Rust Belt battleground by significant numbers" and "with working class voters and Black voters."

"The idea that Harris doesn’t have to specify policy or go before the news media is a strategy born of conceit and foolhardiness and will ultimately backfire," Epstein added.