Democrats are expressing deep concern now that polls show Biden trailing Trump

White House officials on Sunday shrugged off weekend polls that showed President Biden trailing former President Donald J. Trump, even as Democrats said they were increasingly concerned about Mr. Biden’s chances in 2024.

New polls from The New York Times and Siena College showed Biden losing in head-to-head contests with former President Donald J. Trump in five critical swing states: Arizona, Georgia, Michigan, Nevada and Pennsylvania. Mr. Biden is ahead by two percentage points in Wisconsin.

While the polls are worrying for the president, Mr. Biden still has a year to campaign, which his team emphasized on Sunday. They noted that polls have historically failed to predict the results of elections if they were held a year earlier.

“Gallup predicted an eight-point loss for President Obama, but he could win handily a year later,” said Kevin Munoz, a spokesman for Biden’s campaign. “We will win in 2024 by putting our heads down and doing the work, not by worrying about a poll.”

Still, the poll results and other recent studies showing similar results are leading to public declarations of doubts by Democrats.

David Axelrod, a Democratic strategist who has previously expressed concerns about Mr. Biden, wrote on X, formerly known as Twitter, that the new polls will send “tremors of doubt” through the party.

“Only @JoeBiden can make this decision,” Axelrod wrote, referring to whether the president would drop out of the race. “If he continues to run for office, he will become the nominee of the Democratic Party. What he has to decide is whether that is wise; Whether it is in HIS interest or in that of the country?”

In a follow-up interview, Mr. Axelrod said he believed the 80-year-old Biden had accomplished a lot in the past three years but was rapidly losing support, largely because of concerns about how his age is affecting his performance.

“Give me his track record and shave off ten to fifteen years. I would be really confident,” Mr. Axelrod said. “People judge him by his public appearance. That’s what people see. That’s where the erosion took place. It lends itself to Republican messaging.”

Senator Richard Blumenthal, a Connecticut Democrat, said on CNN’s “State of the Union” program on Sunday that he was concerned “before these polls.”

“And now I’m worried,” he said.

“These presidential races have been very close over the last few terms,” he said. “No one is going to have a runaway election here. It will take a lot of hard work, concentration and resources.”

Donna Brazile, a former chair of the Democratic National Committee and a supporter of Mr. Biden, said, “Don’t count out Joe Biden” on ABC’s “This Week” program. But she added that Democrats should take The Times’ polling into account.

“I would like to say again a wake-up call for the Democrats to be reminded that they need to go back and withdraw the coalition that they allowed Joe Biden to break new ground in 2020, especially in Arizona and Georgia , but more importantly, bring that coalition back,” she said. “Without that coalition it will be a very, very difficult race.”

Mr. Munoz declined to comment on the details of the Times/Siena poll.

Julie Chávez Rodríguez, Mr. Biden’s campaign manager, said in a memo released Friday — before the Times poll was made public — that it would be “critical” if Mr. Biden showed strength on key parts of his coalition to win.

The weekend poll results, which included a 10-point deficit behind Mr. Trump in Nevada, strike at the heart of the argument that the president’s campaign advisers have been making for a year: that voters will support Mr. Biden once they see a clear message be presented with. choice between him and his predecessor.

In her memo, Ms. Rodríguez said that “voters will choose between the extremism, divisiveness and incompetence demonstrated by extreme MAGA Republicans – and President Biden’s historic record.

“The American people are on our side when it comes to that choice,” she wrote.

The Times polls gave voters that choice, and many of them, including Democrats, said they would choose Trump if the election were held today.

There were already signs that the campaign is working to address the vulnerabilities shown in the polls among young, black and Hispanic voters.

Last month, the campaign quietly launched two pilot programs aimed at boosting support among Democrats in two key states, Arizona and Wisconsin. In each state, the campaign has hired 12 full-time staffers to test their assumptions about how Mr. Biden is viewed by certain groups and what he needs to do to earn their votes.

In Arizona, the new hires in two offices in Maricopa County will focus on Latino and female voters in that state. In Wisconsin, staffers will work from an office in Milwaukee to evaluate the president’s message for Black and young voters in the state.

Campaign officials say the plan is to use the coming months to test new ways to communicate with those voters. These include the use of ‘micro-influencers’ popular on social media platforms, and ‘relational’ campaigns, where the campaign reaches voters through their network of friends rather than through impersonal advertising.

One of the central arguments of the Biden campaign is the belief that polls conducted now necessarily do not take into account the robust campaign that will unfold over the course of next year.

Mr. Biden has already generated a significant war chest for his campaign. The president and Vice President Kamala Harris have $91 million in cash on hand and are expected to raise hundreds of millions more for use during the general election campaign that will begin in earnest next summer.

The president’s campaign aides say they are confident the polls will shift toward Biden once that money is used to attack Mr. Trump (or another Republican, if Mr. Trump loses the nomination) and reach voters.

That’s similar to the argument Mr. Axelrod made in September 2011, when Mr. Obama was trailing badly in the polls.

“The president remains ahead or in a dead heat with Republican candidates in the battleground states that will decide the 2012 election,” Mr. Axelrod said at the time. “And ultimately it is in those battleground states where voters in fourteen months will choose between two candidates, their record and their vision of the country.”

But Mr. Axelrod said he believed Mr. Biden is now further behind than his 2011 candidate.

He said he believed Biden would continue to run for re-election, and that he would likely face Trump again next year. He urged Mr. Biden and those around him to attack Mr. Trump politically to make clearer what a Trump victory in 2024 would mean for the country.

That kind of “competitive framework” is more important now, Mr. Axelrod said, than telling people about Mr. Biden’s achievements.

“I think he’ll run,” Mr. Axelrod said. “I think he will be the nominee. If that is the case, they have to put the whole campaign very quickly into a very, very competitive framework.”