“She has things in her plan that are just not realistic, but if you question it, she says you don’t understand or you’re talking like a Republican,” Biden said on continued. “It’s just an elitist attitude that it’s either my way or the highway.”

Calling Warren “elitist” is an attempt by Biden to paint Warren as too extreme for the Democratic electorate. He's looking to stoke resentment among working class voters by casting Warren as a snooty, liberal Harvard professor and not the person she portends to be on the campaign trail: a scrappy Oklahoman taking on Washington corruption.

It comes as Biden is looking to blunt Warren’s momentum as she overtakes him in early state polling.

Biden’s play is centered on Medicare for All, long used as a wedge issue by his campaign to define the former vice president as the moderate battling a cast of Democrats who have moved too far to the left.

Biden built on an inflammatory Medium post he published Tuesday, in which he wrote, “Some call it the ‘my way or the highway’ approach to politics. But it’s worse than that. It’s condescending to the millions of Democrats who have a different view."

He continued, “It’s representative of an elitism that working and middle-class people do not share: ‘We know best; you know nothing.’ ‘If you were only as smart as I am you would agree with me.’ This is no way to get anything done.”

There are risks for Biden attempting to paint Warren as elitist, given the mechanisms in which they fund their campaigns. Warren has shunned big-dollar donors and fundraisers; her reliance on grass-roots money has helped catapult her to the top of the field in early states as she swamped Biden in fundraising from July through September. Warren has faced criticism because she made the move only after transferring $10 million out of her Senate campaign fund, which includes money raised through the very methods she now rails against.

Sen. Elizabeth Warren.

Biden has also come under scrutiny over his use of private jets and for staying in posh hotels even as his campaign spent $2 million than it raised in the last fundraising quarter. While Warren relied on small dollar donors to bring in $25.7 million last quarter, Biden relied heavily on private fundraisers and raised just $15.7 million. What’s more, Biden took the unusual step of softening his opposition to a super PAC to support his candidacy, even as the rest of the field has moved away from a funding mechanism allowing unlimited contributions.

“Joe Biden's message is resonating with the biggest, most diverse coalition of any candidate — and especially with working people,” said Biden spokesman Andrew Bates. “He’s running to rebuild the American middle class, with everyone in on the deal this time, by winning key battleground states instead of political Twitter. Protecting and strengthening the Affordable Care Act is at the heart of Joe Biden’s case, and he was strongly encouraged by the results that similar arguments achieved in Virginia and Kentucky last night.”

Though Biden did not name Warren in his essay, it was apparent that he was referencing the Massachusetts senator who snarked that the former vice president was running in the wrong primary after he criticized the vague contours of how she would pay for her $20 trillion Medicare for All plan.

"So if Joe Biden doesn't like that, I'm just not sure where he's going," she said Friday. "Democrats are not gonna win by repeating Republican talking points. … If anyone wants to defend keeping those high profits for insurance companies and those high profits for drug companies, and not making the top 1 percent pay a fair share in taxes, and not making corporations pay a fair share in taxes, then I think they're running in the wrong presidential primary."

The barb prompted Biden to write the essay outlining all his accomplishments for the Democratic Party throughout his career.

And he did not back down when asked about his criticisms of Warren in an interview Wednesday morning.

This is not the first time the two candidates have butted heads. They exchanged barbs in the October debate after Biden’s claim that he was the only candidate with major legislative achievements. Warren pointed to her own work, including helping create the Consumer Financial Protection Bureau after the financial crisis.

“I convinced people to vote for it,” he insisted.

“I am deeply grateful to President Obama, who fought so hard to make sure that agency was passed into law.”