A new poll reveals growing concern among Democratic voters about President Joe Biden’s mental fitness following a shaky debate performance on Thursday. The CBS News/YouGov poll, released on Sunday, shows that 72% of registered voters believe the president lacks the mental and cognitive health to serve as president, a significant increase from the 65% who expressed the same concern in an earlier poll. By comparison, 49% of voters questioned former President Donald Trump’s mental fitness.

The poll’s findings are particularly troubling for Biden’s campaign, as 45% of registered Democrats polled think he should step aside for another candidate. Concerns about the ages of both Biden, 81, and Trump, 78, have been ongoing, but Biden’s hoarse voice and muddled answers during the debate have intensified worries among some Democrats, prompting calls for him to step down.

Despite these concerns, Biden’s family encouraged him to remain in the race during a long-planned visit to Camp David on Sunday, according to a source familiar with the discussions who spoke to CBS News, BBC’s US partner.

Maryland Congressman Jamie Raskin, a Democrat and White House ally, described the situation as “difficult” in an interview with MSNBC on Sunday. He acknowledged that “honest and serious and rigorous conversations” are happening within the party, but emphasized that the final decision rests with Biden. Raskin added, “Regardless of what President Biden decides, our party is going to be unified and our party also needs him at the very centre of our deliberations in our campaign.”

In the aftermath of the debate, prominent figures including First Lady Jill Biden, Vice President Kamala Harris, and former President Barack Obama have acknowledged that Biden’s performance was not his best but have dismissed calls for him to step aside. House Minority Leader Hakeem Jeffries told MSNBC on Sunday, “The president’s debate performance was a setback. But, of course, I believe a setback is nothing more than a setup for a comeback.”