▶ Watch Video: Khanna says centrist Democrat could challenge Biden in 2024

Rep. Ro Khanna of California, a leading progressive Democrat, said Monday that centrist Democrats could pose the biggest political threat to President Joe Biden in the 2024 presidential primary race, one day after Sen. Joe Manchin of West Virginia did not rule out a possible White House bid.

“I think the irony is they’ve been the ones criticizing the president far more than the progressive left,” Khanna said in an interview with CBS News about policy and the coming 2024 election.

And Khanna believes that fellow Biden allies should not dismiss the possibility that Manchin or someone similar might challenge Mr. Biden.

“I don’t rule it out,” he said of a primary challenge to Mr. Biden from a business-friendly Democrat. “I think [Biden] would win decisively against such a challenge and it would be unfortunate. But you know, I don’t rule it out.”

Mr. Biden has long said he intends to run for reelection, although he has not yet made a final decision or announcement. Biden confidants including Rep. James Clyburn, Democrat of South Carolina, have told CBS News in recent weeks that they are convinced Mr. Biden will run and have urged Democrats not to challenge him.

When asked whether he thinks Mr. Biden could face a progressive primary challenger, Khanna allowed that it’s possible, but he does not believe Mr. Biden would “face a serious challenge” from the left. 

Should the president decide not to seek reelection, Khanna said independent Sen. Bernie Sanders, of Vermont, who caucuses with the Democrats in the Senate, might jump into the 2024 race for a third White House bid.

“Sure, why wouldn’t he?” Khanna said. “He’s built a huge movement.”

Khanna added, “He’s been championing ‘Medicare for all,’ free public college, a livable wage, and childcare for everyone. Of course, I think he would look at it. And he was almost the nominee last time.” In 2020, Sanders won the New Hampshire primary and performed well in other states, staying in the Democratic race until he suspended his campaign in early April 2020, following Mr. Biden’s gains in the Super Tuesday contests and other rivals endorsing Biden’s candidacy.

Khanna, who served as a national co-chair of Sanders’s 2020 presidential campaign, underscored that a Sanders 2024 campaign is not something he is pushing and said he and Sanders both remain supporters of Mr. Biden and expect the president to announce his plans in the coming months. 

Meanwhile, the president continues to face mounting criticism from some Democrats on his handling of materials with classified markings found at his former office and at his home. 

On NBC’s “Meet the Press” on Sunday, Manchin did not rule out a possible 2024 presidential run and said, “I’m going to do everything I can to make sure that when I make my decision, I make it on based on what’s best, what I think I can do to support, and best for my country and my state.”

“I haven’t decided on anything I’m going to do until I see the lay of the land is going to be at that time,” Manchin said.

Manchin also called Biden’s handling of classified materials “irresponsible” and said he supports Attorney General Merrick Garland’s decision to appoint a special counsel to investigate the matter.

“To be held accountable and responsible is what we all are,” Manchin said. “And to put those in unsecured spaces is irresponsible.”

Khanna told CBS News that he believes Mr. Biden has “handled this with character” and is fully cooperating with investigators. 

“I expect him to” announce in the coming weeks, and “I would support him if he does,” Khanna said of Mr. Biden. “Everything I’ve heard leads me to believe that the vast majority of Democrats will support him.”

As for his own political career, Khanna is considering a possible 2024 Senate run in California but is waiting to see whether his colleague and veteran progressive lawmaker, Rep. Barbara Lee, gets into the primary race. 

“A lot of Bernie Sanders delegates have asked me to look at the race, and I will look at the race in the next few months,” he said. “But my very good friend Barbara Lee is considering the race. I have tremendous admiration for her. She’s my neighbor and I have said that it will weigh heavily on me in factoring in to my decision — what Barbara Lee does.”

Fernando Suarez contributed.