Biden’s call fails to stifle criticism from Democrats in Congress

President Biden’s brazen appeal to Democrats in Congress to stop questioning his viability and rally behind his candidacy has done little to dampen the wave of skepticism within his own party that has engulfed his campaign.

As lawmakers returned to Washington after a weeklong recess, there was little sign that Biden’s efforts to reassure his allies — whether through a blunt letter or a phone interview on MSNBC — had done much to assuage growing concerns among Democrats.

Instead, ahead of a day of crucial meetings in which House and Senate Democrats plan to meet separately to discuss a path forward, lawmakers were still openly agonizing over their presumptive nominee, with partisan differences over the best course of action bursting into view. And two other prominent Democrats came forward to voice concerns about Biden’s path to victory in November.

“With so much at stake in the upcoming election, it is time for conversations about the strongest path forward,” Sen. Mark Warner, Democrat of Virginia and chairman of the Intelligence Committee, said in a statement. “As these conversations continue, I believe it is incumbent on the President to more aggressively advocate his case to the American people, and to hear directly from a broader range of voices on how best to prevent Trump’s lawlessness from returning to the White House.”

Representative Adam Smith of Washington, the top Democrat on the Armed Services Committee, became the latest — and perhaps the most prominent — lawmaker to publicly say Mr. Biden should resign, after first saying so Sunday in a closed-door meeting of top House Democrats.

“I think it’s become clear that he’s not the best person to get the Democratic message out there,” Smith said in an interview on CNN on Monday, adding: “I personally think Kamala Harris would be a much better, stronger candidate.”

Biden started the day by sending a letter seeking to silence any further calls to step aside and put an end to the whining on Capitol Hill.

“The question of how to move forward has been raging for more than a week,” Biden wrote in his two-page letter to lawmakers. “And it is time for it to end.”

But on Capitol Hill, there was no end in sight, with only a few Democrats in Congress unequivocally backing Biden.

Nevada Sen. Catherine Cortez Masto, whose 2022 victory flipped control of the Senate to Democrats, said in a statement that Biden “has always had the support of Nevadans, whether it’s on the picket lines, protecting our personal freedoms, or lowering costs — now it’s time for us to have his.”

And Biden’s strong support base within the Congressional Black Caucus grew, with its chairman, Rep. Steven Horsford of Nevada, issuing a statement defending the president.

“President Biden is the nominee and was chosen by millions of voters across this country, including voters in Nevada,” he wrote in a social media post, adding that voters “know that President Biden and Vice President Harris are fighting for them.”

Biden has scheduled a virtual meeting with the Black Caucus, an influential group on Capitol Hill, for Monday night, hoping to capitalize on its support and perhaps dissuade others from breaking with a powerful part of the Democratic coalition.

Delaware Sen. Chris Coons, a Biden confidant and co-chair of his campaign, stated bluntly: “President Biden will be the nominee of my party.”

The overall mood in Congress, however, was much more somber, as lawmakers returning to Washington for the first time since Biden’s disastrous performance in the debate quietly worried about his ability to defeat former President Donald J. Trump and the pressure he could put on Democratic candidates for seats in the House of Representatives and the Senate if he continued his campaign.

Many Democratic senators have long considered Mr. Biden, a creature of the Senate who served there for more than three decades, a personal friend and ally. But most have suggested that it is the president’s responsibility to assuage any concerns voters may have about his age and fitness.

Some seemed reluctant to say much on the issue before Tuesday, when Democratic senators plan to discuss Mr. Biden’s future at their weekly private holiday luncheon. House Democrats are expected to have a similar discussion at their weekly caucus Tuesday morning. But those who did weigh in made clear they had deep concerns about Mr. Biden continuing as the party’s nominee.

“I love Joe Biden,” said Sen. Martin Heinrich, Democrat of New Mexico, in what has become a signature phrase among his colleagues. “He’s the most successful president of my lifetime, and he’s a genuinely great human being. But what I care about most is preserving our democracy.”

Mr. Heinrich, who is seeking re-election this year, continued: “President Biden must continue to demonstrate that his debate performance was simply a bad night, and that he has a clear path to defeating Donald Trump. Our democracy hangs in the balance.”

Sen. Brian Schatz of Hawaii said in a terse statement that “the most important thing for Democrats or for the country is to defeat Donald Trump,” and that Democrats “need to have personal family conversations about the best way to do that.” He declined to comment further.

Sen. Michael Bennet of Colorado also declined to pledge to support Biden as the party’s nominee, saying Democrats needed to discuss the best way to win the White House and both chambers of Congress. “I want him to succeed,” Bennet said.

Sidelining Biden, he continued, would not be “anyone’s first choice.”

“But we have a moral obligation to the country to determine that we can win the presidency, that we can win the House of Representatives, that we can win the Senate,” he said. “We have to do that. We are here this week to have that conversation.”

Others offered terse statements of support. Sen. Chuck Schumer of New York, the majority leader, has mostly repeated a clipped message of approval over the past week. “I stand with Joe,” he told reporters on Monday as he entered the Capitol. “I have no interest in walking away from him,” Sen. Thomas R. Carper, Democrat of Delaware, told reporters outside his office.

And Democratic senators running in the country’s most politically dangerous races, including Ohio and Montana, refused to provide the president with any political cover.

When Ohio Sen. Sherrod Brown was asked at a campaign rally whether Biden should run for re-election, he replied, “I’m not an expert.”

“I’ve talked to people all over Ohio,” Mr. Brown said. “They have legitimate questions about whether the president should continue his campaign, and I’m going to continue to listen to people.”

And Senator Jon Tester of Montana issued a statement saying that Mr. Biden “must prove to the American people — including me — that he is up to the task for another four years.”

Robert Jimison, Annie Karni And Maya C. Miller contributed to the reporting.