Democratic presidential candidate, U.S. Rep. Dean Phillips, D-Minn., addresses guests during a campaign stop, Tuesday, Oct. 31, 2023, in Manchester, N.H.
MANCHESTER, N.H. CNN  — 

Rep. Dean Phillips is escalating his long-shot presidential primary challenge to President Joe Biden, vowing to invest as much of his multimillion-dollar fortune as it takes to win.

His defiance comes in the face of overwhelming rejection from his fellow Democrats, a reaction so fast and furious Phillips believes he’s torpedoed his own congressional career.

But instead of backing down, Phillips is opening the door to super PAC money that could air millions of dollars’ worth of negative ads in primary states that are likely pivotal in the general election, including Michigan and New Hampshire. And he’s escalating his attacks against the president’s message and political standing.

“I think in 2020, (President Biden) was probably the only Democrat who could have beaten Donald Trump. I think in 2024, he may be among the only ones that will lose to him. And that’s why I’m doing this,” Phillips told CNN in a lengthy interview Saturday.

Phillips says he’s likely tanked his future in Democratic politics by taking on Biden in what his critics say is a quixotic presidential primary challenge. But the angry reactions from his own party seem to motivate him.

Biden’s “approval numbers are historically low, rivaling only Jimmy Carter, who got slaughtered, of course, in that election,” Phillips said, referring to President Carter’s general election loss in 1980 after he faced a primary challenge from Democratic Sen. Ted Kennedy. “[Carter] had a Democratic primary challenger because he was going to get slaughtered in the election. It’s the same circumstance again. Ted Kennedy did not cause Jimmy Carter’s problems. I did not cause President Biden’s problems.”

And Phillips launched a direct attack on one of the core messages of Biden’s reelection campaign: “Bidenomics is not working. It is actually the opposite. It represents inflation, high prices,” he said.

Phillips has been campaigning against Biden for just over two weeks, and in that time he’s seen many of his fellow Democrats rise up against him. He left his leadership post in the House of Representatives after he was criticized during a private caucus meeting. He would face multiple primary challengers should he run again in Minnesota. And he’s taken heat from the powerful Rep. Jim Clyburn of South Carolina, who said Phillips is disrespecting the Black voters who powered Biden’s win and have been a bedrock constituency of the modern Democratic Party.

Speaking to CNN in the library of the New Hampshire Institute of Politics, with signs from campaigns won and lost in decades past adorning the walls behind him, Phillips compared himself to Sen. Eugene McCarthy, who famously came close to defeating incumbent Democratic President Lyndon Johnson in the 1968 New Hampshire primary. Many view McCarthy’s run as a critical part of Johnson’s ultimate decision not to run for reelection.

“I think what Gene McCarthy did in 1968 was actually helpful,” Phillips said.

“I do believe Johnson would have lost, it opened the door to Bobby Kennedy, who — had he not been assassinated — absolutely, I believe, would have won that election in 1968,” Phillips said. “And I think we need more of that kind of courage. People were willing to torpedo their own career, which I believe I’ve done.”

Asked Saturday by CNN if there was a limit to the dollar amount of his own considerable personal fortune he was willing to spend, he answered: “No.”

And when pressed about whether he would discourage super PACs from spending money on his behalf, he said: “You have to play by the rules until you can change them … I can’t deny support from anybody.”

Phillips is a political neophyte, elected to Congress in 2018 after, in his telling, Donald Trump’s election devastated his two daughters and inspired him to get involved. Before that, he had been running his family’s alcohol business, and for a time ran the gelato company Talenti. He is worth as much as $77 million, according to financial disclosures.

His affable personality quickly endeared him to colleagues, and he became the co-chair of the Democratic Policy and Communications Caucus.

But Phillips’ presidential campaign so far has demonstrated a distinct lack of familiarity with the core power centers of the Democratic Party. Asked Saturday about his outreach to key groups representing Black voters’ interests, including the Congressional Black Caucus, Urban League and NAACP, Phillips acknowledged he had not been in contact with any of them before he announced his campaign Oct. 27 or since.

“I’ve only been at this two weeks. Of course I’m going be speaking to everybody,” he said.

How is his message distinct from Biden’s? Phillips said he differs from the president on border policy and would make people who need to claim asylum do it from their home countries. And he said he would do more than Biden has done to improve affordability by letting Americans deduct essential expenses like clothes and groceries on their taxes.

Phillips said he plans to campaign next in South Carolina, the state whose Black voters helped send Biden to the Democratic nomination in 2020 after Clyburn endorsed the now-president. Then, Phillips says, he’ll focus on Michigan, which votes Feb. 27.

If after March 6 – known as “Super Tuesday,” when dozens of delegates are up for grabs – Phillips hasn’t come out ahead, he says, he’ll get out of the race and campaign for the Democratic nominee.

And he says he won’t run as a third-party candidate.

“I’m running in a primary. I’m not doing what Cornel West is doing, not doing what Jill Stein is doing, not doing what Joe Manchin might do,” Phillips said. “If the president beats me in New Hampshire and Michigan, all around the country, that’s good. He looks strong. If I force the president to have to get out and campaign basically for the first time — because he didn’t have to campaign in 2020 — and he appears well, and he debates and he’s strong, makes a good case, that’s good for him.”

He added: “I could win this. I intend to win this. Or I could open the door for others who might be better positioned to beat Donald Trump.”