Another major poll shows the vast majority of voters don't think Biden is physically fit to serve as president

• Concerns about Biden's mental and physical fitness continue to dog his reelection campaign.
• On Sunday, two separate polls said most adults and voters think he's too old and not fit enough.

As 81-year-old Democratic President Joe Biden continues to dominate Democratic state primaries, poll after poll shows the vast majority of US adults and likely voters think he's either too old or not fit enough to serve another four years.

A poll released Sunday by YouGov/CBS News revealed that just 26% of adult respondents said "only Joe Biden" has the "mental and cognitive health" to serve as president in 2025. Trump, by comparison, received 43% of the vote, while 25% of respondents said "neither."

The New York Times/Siena College released results from a similar poll on Sunday as well, revealing that 72% of its likely voter respondents either "strongly" or "somewhat" agreed Biden's too old to serve an additional term. While that figure was inflated by conservative respondents, more than half of all Democrats surveyed felt similarly.

Additionally, a poll from Monmouth University in February found that just under 1-in-3 voters felt confident in Biden's mental and physical strength.

Each of the three polls was taken in the weeks following US Special Counsel Robert Hur's report on the president's mishandling of classified documents, which specifically highlighted perceived instances of Biden's advanced age taking a toll on his memory.

But in light of Biden's rough polling and increased calls for him to drop out of the 2024 presidential race, don't expect his party to step in anytime soon: Democratic National Committee Chair Jaime Harrison recently said in a late-night X post he thought it was "certifiably crazy actually" to believe the party could "usurp the nomination" and still win in November.

However, Trump's mental acuity is also under scrutiny, especially after the former president has continued to brag about his performance on a test designed to detect cognitive decline.

As the 77-year-old Trump continues to hold campaign rally after campaign rally, he's repeatedly mixed up Biden and former President Barack Obama in speeches and stumbled over some words and phrases.

Neither Trump nor Biden have officially secured their party's presidential nomination. But both have dominated their party's primary contests and appear on track for a likely rematch in November.