Former Clinton pollster Mark Penn said on "America's Newsroom" Monday that a new poll showing President Biden with just 36% approval will "send shockwaves" through the White House and Democratic Party. The CEO of Stagwell Group said Biden's "rushed" re-election announcement was a mistake, as former President Trump leads Biden by six points and Florida Gov. Ron DeSantis leads Biden by five in a new Washington Post/ABC poll.

SEN. COONS GOES ON DEFENSE AS ONE ISSUE CONTINUES TO HURT BIDEN IN POLLS WITH HIS OWN PARTY

MARK PENN: When he drops here from 42 to 36 in approval in this poll, that's all Democrats who are jumping ship and saying, I don't approve of the presidency he's doing. And I think we've seen for a long time. Look, the Harris polling showed the same thing for a long time. People question his fitness for continued office. Most Democrats didn't want him to run. But this poll has to send shockwaves. He just announced for presidency. You're supposed to go up when you announce, not down.

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President Joe Biden

President Joe Biden, 80, announced he would seek re-election.  ((Photo by Anna Moneymaker/Getty Images))

I think the announcement, I think the fact that he said he's running for president when less than 40% of Democrats really support his re-election. Remember, they rushed up this announcement. It was supposed to be in July. That would have given everyone an opportunity to see how he's doing and not freeze the field. Instead, he froze the field in the Democratic Party. Everybody's got to support him now and with numbers like this, they're looking at a potential Titanic at this point unless it changes.

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President Biden is facing significant headwinds at the start of his re-election campaign, with the vast majority of Americans saying he doesn’t have the physical or mental capacity to serve another term, according to a new poll.

An ABC News/Washington Post poll released Sunday found that 63% of American adults do not think Biden, 80, has the "mental sharpness" it takes to serve effectively as president, compared to only 32% who believe he does and 5% who have no opinion. The number shot up nine percentage points since the same poll was conducted a year ago when 54% said he didn’t have the mental capacity for the job.

The poll found that 62% of Americans do not think Biden is in "good enough physical health" to serve either, compared to 33% who believe he is and 5% who have no opinion.

Fox News' Jessica Chasmar contributed to this report.