(NewsNation) — Mark Penn, a former pollster for Bill Clinton, cautioned that the 2024 presidential election could be decided by an “uninformed electorate” operating on “vibes” rather than substantive policy differences between candidates Kamala Harris and Donald Trump.

In a Tuesday interview on NewsNation’s “On Balance,” Penn emphasized the importance of presidential debates, policy papers and tough press questions to inform voters. He expressed concern about the lack of these traditional campaign elements in the current race.

“The whole question is, will the issues become salient, or will some kind of personality and vibes dominate?” Penn said.

The pollster noted a disconnect between voters’ issue preferences and their current candidate support. He cited his own poll shows 68% of respondents oppose open borders, with 70% believing Harris supporting them, yet this isn’t reflected in voting intentions.

Penn predicted the economy would be the deciding factor for undecided voters.

“The real undecideds are about the economy,” he said. “That’s really the issue that is going to sway voters one way or another.”

He urged campaigns to focus on economic issues after Labor Day, warning that the candidate who fails to effectively address economic concerns “is going to lose.”

Penn also suggested Harris may reach her polling peak following the Democratic National Convention, predicting little room for further voter shifts in her favor.

The former Clinton adviser called for a return to substantive campaigning, including three presidential debates and comprehensive policy proposals from both candidates.