Sen. Joe Manchin on Sunday called on Joe Biden to end his re-election campaign and “pass the torch to a new generation,” the latest domino to fall in a broader Democratic unrest over the president’s ability to win this November.

“He’s going to go down in history with a legacy that no one else knows, as one of the best and truly a (patriotic) American,” Manchin said. “So, with that in mind, I come away with a heavy heart to think that the time has come for him to pass the torch to a new generation.”

Manchin (IW, Va.), who joined the Democrats but left the party earlier this year, told “This Week” co-host Martha Raddatz that the wave of Democrats making similar calls after last month’s debate made the current situation untenable for Biden.

“The first week after the debate, I thought the president needed time to evaluate and make a decision if he was going to do that at that point, and then I thought, well, we’re going to hear from my colleagues who are in very difficult, challenging areas of the country, whether it’s in Congress, in terms of their districts, or in the states, in terms of my senators, and they’re speaking out now. And then when you see the donor class, basically, speaking out and saying they’ve gone in a different direction, if you want to call it that,” he said.

Manchin argued that by withdrawing now, Biden would be able to address a range of issues he considers a priority, including unifying the country, ending the fighting in Gaza and helping Ukraine fend off the Russian invasion. He would also be able to “show the rest of the world that the transition of power from the world’s superpower is happening in an orderly manner.”

Concerns about Biden’s electoral future have grown after last month’s debate, in which Biden looked vacant and gave answers that were at times incoherent.

Manchin said he has seen nothing in his personal interactions with Biden that would cause him to worry about the president’s mental acuity. He did acknowledge, however, that “it is concerning when you see him” on the campaign trail, even though the two have not spoken in the past three weeks.

The West Virginia Democrat said he still believes Biden can finish his term, noting that while a national campaign takes an “incredible” toll, “he can finish the job he started in the way he wants to lead.”

Still, Biden has remained adamant that he will stay in the race, despite calls from more than three dozen lawmakers to withdraw, a number that continues to grow. And as he digs in, he retains defenders on Capitol Hill.

Congressman Ro Khanna (D-Calif.) has been campaigning for Biden across the country, warning that pressure on the president to resign could upset some voters.

“One of the things we underestimate is that Joe Biden actually has a coalition, African-American women, working-class people, seniors who voted for him, and if he feels outraged, those voters are going to feel outraged. So, it’s his decision,” Khanna told Raddatz on “This Week” on Sunday. “You can’t just let somebody put together a ticket after the fact that may not be consistent with where the Democratic electorate is.”

Khanna then listed Biden’s accomplishments, including significant infrastructure investments, noting that despite longstanding concerns about the president’s age, no major candidate has endorsed him.

“It’s his decision about what he wants to do, and I trust him. I trust his patriotism to make the right decision. And there’s a process in this country. If you’re going to run for president, go get votes in New Hampshire, in South Carolina, in Nevada,” Khanna said.

If Biden withdraws, it is unclear what the next step will be.

Some within the party argue that Vice President Kamala Harris is the next frontrunner for the nomination, but others argue that a more open process would be beneficial to the party.

“Healthy competition is what this is all about,” Manchin said Sunday. “And that’s why I believe it should be an open process.”

When asked if Harris could win, Manchin replied that “the process would determine” whether she could, though he did name Gov. Andy Beshear of Kentucky and Gov. Josh Shapiro of Pennsylvania as two Democrats who have been able to govern effectively in red and purple states — and who have also been mentioned as future potential presidential candidates.

“There are a lot of good people out there. I want to stand behind and support whoever can pass a comprehensive proposal,” Manchin said.

Khanna indicated she was confident Harris would have an edge given her current spot on the national ticket.

“I believe the vice president would win that vote,” he said Sunday. “I don’t think you’re going to see many people challenging her. I mean, these are Biden-Harris delegates. It’s not an open primary. I think if it was an open primary, there should be a lot of candidates.”