Washington
CNN
 — 

President Joe Biden told congressional Democrats in a letter on Monday that he will continue his reelection bid despite mounting concerns about his mental fitness and the viability of his campaign, while also hitting back at party “elites” in an interview ahead of a critical week on Capitol Hill.

“I want you to know that despite all the speculation in the press and elsewhere, I am firmly committed to staying in this race, to running this race to the end, and to beating Donald Trump,” Biden wrote in the letter, obtained by CNN.

Biden sought to put growing concerns about his viability to rest in the forcefully worded letter.

“The question of how to move forward has been well-aired for over a week now. And it’s time for it to end. We have one job. And that is to beat Donald Trump. We have 42 days to the Democratic Convention and 119 days to the general election. Any weakening of resolve or lack of clarity about the task ahead only helps Trump and hurts us,” Biden concluded. “It is time to come together, move forward as a unified party, and defeat Donald Trump.”

It’s a critical week for Biden’s political future as he seeks to tamp down intensifying fallout with the House and Senate back in session for the first time since the debate. More than a handful of top House Democrats told Minority Leader Hakeem Jeffries on Sunday that Biden needs to step aside amid concerns about down-ballot Democratic races.

Shortly after the letter was released, Biden called into MSNBC’s “Morning Joe,” part of a strategy to do more “off-the-cuff,” unscripted engagements to quell concerns about his age.

But the appearance, while energetic, may not have had its intended impact.

Biden offered a lengthy and occasionally off-topic response to a question about his letter to Hill Democrats calling for unity and lambasted Trump for being on the golf course after the debate. Trump has largely stayed under the radar while Biden battles the news cycle.

“Well look — Democrats — Joe, let me say it this way, the reason I’ve been on the road so much, all over the country, while Trump is riding around in a golf cart, filling out his golf cart before, golf cart before he even hits the ball — but anyway, he hasn’t been anywhere in 10 days, I’ve been all over the country, No. 1,” he said.

He continued: “And I’ve gone over the country for several reasons, one, to make sure my instinct was right about the party still wanting me to be the nominee. And all the data, all the data shows that the average Democrat out there who voted, 14 million of them who’ve voted for me, still want me to be the nominee, No. 1.”

And in a pointed rebuke to his critics, Biden said, “I’m getting so frustrated by the elites. Now, I’m not talking about you guys, but by the elites in the party. They know so much more. But if any of these guys don’t think I should run, run against me. Go ahead. Announce — announce for president. Challenge me at the convention.”

The president will continue his outreach to Democratic lawmakers this week, a campaign official tells CNN. Tuesday will be a consequential day as members are set hold a planned caucus meeting with Jeffries, and one member told CNN they anticipate that is the day when the dam will break.

Congress returns to Washington on Tuesday for the first time since the June 27 debate on CNN that prompted widespread concern over Biden’s ability to secure a victory for Democrats in November and to serve an additional four years in office.

In the week following his disastrous debate performance, Biden personally reached out to roughly 20 House Democrats, a campaign official tells CNN, and has spoken with party leaders — including Senate Majority Leader Chuck Schumer, House Minority Leader Hakeem Jeffries, and Reps. Nancy Pelosi and James Clyburn — with a goal of reassuring them that the concerns within the party are being heard.

Since then, Schumer and Clyburn have voiced support for Biden, while Jeffries has remained mum.

Pelosi has said the questions surrounding Biden’s disastrous performance at the presidential debate were “legitimate.”

Asked about Pelosi’s comments, Biden told ABC News, “it was a bad episode. No indication of any serious condition. I was exhausted.”

On a call with senior House Democrats convened Sunday by Jeffries, a half-dozen lawmakers voiced their own concerns during a conversation one aide described to CNN as “pretty brutal.”

Those lawmakers — which CNN has reported to include Reps. Jerry Nadler, Adam Smith, Mark Takano and Joe Morelle — represent the highest-ranking Democrats on the Judiciary, Armed Services, Veterans Affairs and House Administration committees.

A campaign official declined to say whether the president had spoken directly with Sen. Mark Warner, the Virginia Democrat who organized a concurrent effort among like-minded senators to explore the possibility of an official request for Biden to step aside. Warner canceled a follow-up meeting scheduled for Monday evening, a source tells CNN, after news of the group’s efforts leaked. The next meeting will be Tuesday with Senate Democrats and their leadership.

Biden told ABC News that Warner was a “good man” but has a “different perspective.”

Biden’s campaign on Monday highlighted a list of supportive statements from Hill Democrats, seeking to amplify the voices who have expressed confidence in the president’s candidacy in recent days.

Also on Monday, the Biden campaign is hosting a donor call with its national finance committee, a source familiar with the call said, another sign of outreach. A senior Democratic adviser told CNN that Biden is expected to join the call, underscoring a top concern of the campaign about whether donors will continue to back him or redirect their money to House and Senate campaign efforts if he stays in the race.

Campaign chair Jen O’Malley Dillon will lead the call, and Maryland Gov. Wes Moore is expected to be among the speakers joining, the source said.

The call is expected to take place around 12 p.m. ET, and it’s unclear how many donors will join. The campaign held a similar call last week where O’Malley Dillon defended the president’s health and said the team was “clear-eyed, not pollyanish” about the president’s debate performance. About 500 donors joined that call.

Moore was among the governors who met with Biden at the White House last week, telling reporters after the meeting he supports the president but acknowledged the concerns from voters.

“We always believe that when you love someone, you tell them the truth. And I think we came in and we were honest about the feedback that we were getting. We were honest about the concerns that we are hearing from people,” Moore said.

He continued, “And we’re also honest about the fact that as the president continued to tell us and show us that he was all in, that we said that we would stand with him.”

CNN’s Jeff Zeleny contributed to this report.