 Debate prep is path forward. It's not clear what polling he was referencing. However, a new poll after the debate from CBS News and YouGov finds that 72% of registered voters said Biden should not be running for president, while only 28% said he should be. If Democrats were to replace Biden, a collapse at the top of the ticket could filter down to the roughly half-dozen races in which Democratic-held seats and thus control of the Senate were at risk of falling into Republican hands.