Democratic presidential candidates Sen. Bernie Sanders, I-Vt., and former Vice President Joe Biden.
Steve Helber—AP; Chris Carlson—AP
March 5, 2020 9:25 PM EST

After months of internal hand wringing, the Democratic Party’s biggest financial backers have flocked to former Vice President Joe Biden. And Bernie Sanders, the Vermont Senator running as the scourge of the elite, is trying to turn it against him.

“The political establishment of this country is frantically trying to stop us,” the Sanders campaign wrote in a fundraising e-mail Thursday morning, one of several circulated since Biden’s big wins on Super Tuesday. “They’re now fully behind their candidate, Joe Biden, and their super PACs are spending big on advertising against us. So we need a lot of donations today in order to take them on and win.”

As the Democratic presidential race shifts into a two-person contest, two campaigns with two very different funding models are now being put to the test: Biden’s bid backed by longtime Democratic donors and bundlers who have now united behind him, and the massive grassroots movement of small-dollar donations that has fueled Sanders.

In a sense, the dueling models are a microcosm of the competing visions for the Democratic Party itself: whether it will continue operating under the status quo, or shift towards the grassroots-led model the progressive wing has been pushing for years. Whoever prevails will not just get the party’s nomination, but could possibly determine its future financial model.

Biden has never been reputed for his fundraising prowess, and until just a few days ago, a wide field of moderate candidates was spreading donor money thin. He raised just $8.9 million this past January, according to documents filed with the Federal Election Commission, while Sanders raised over $25 million. His competitors were badly outspending him in the weeks preceding Super Tuesday, reinforcing the shock values of his victories.

But since the former Vice President’s landslide victory in South Carolina, followed by his series of wins in the March 3 Super Tuesday contests, all candidates except Sanders and former Hawaii Rep. Tulsi Gabbard have dropped out and the money has been pouring in. The campaign reportedly announced Wednesday it had raised $7.1 million – nearly the entirety of its January haul – in a two-day window that included Super Tuesday as Democratic donors who had previously remained neutral or supported competitors like Pete Buttigieg and Amy Klobuchar opened their pocketbooks.

“The folks who, for a long period of time would not give me money for the campaign because they did not think [Biden] was going to be the leading candidate turned — particularly turned when Pete [Buttigieg] and Amy [Klobuchar] came on board and since [Michael] Bloomberg dropped out,” says attorney Stephen Cozen, founder of the law firm Cozen O’Connor and a Philadelphia-based Biden donor who has been raising money since he entered the race. “I’ve had a tremendous influx of contributions to the campaign from people who have said ‘You were right all along.'”

Bundlers who had worked for Buttigieg are also jumping on the Biden train. “Some want to wait until after tonight’s results or beyond before choosing who to support – I respect that,” Alex Slater, a fundraiser for Buttigieg, wrote in an e-mail, reviewed by TIME, that announced to the former Mayor’s supporters that he would be supporting Biden. But, Slater continued, “I have personally come to the belief that the political moment deserves action and conviction.”

Other Buttigieg supporters also say it’s just a matter of time until they throw their support behind him. “Of course we’re [going] to support Joe,” says one Buttigieg fundraiser, while acknowledging that some had not done so yet. The Biden campaign has already held calls with Buttigieg bundlers, this person said, and will hold at least two more on Friday.

Sanders’ campaign started off the year on steadier financial footing. At the end of January, when Biden’s campaign only had about $7 million cash on hand, Sanders had nearly $17 million. In February, his team raised a staggering $46 million. And his success has come from a very different source.

According to January’s filings with the Federal Election Commission, 53% of the $25 million Sanders received in campaign donations were unitemized, or under $200. Biden could say the same for about 35% of his campaign donations.

In both fundraising emails and stump speeches, Sanders is using this discrepancy to bolster his claims that “the establishment” — a term loosely defined as longtime party stalwarts and fundraisers that he frequently invokes — is on a mission to undermine his progressive movement.

“Joe is running a campaign that is obviously heavily supported by the corporate establishment,” Sanders said at a press conference Wednesday in Vermont. He noted that Biden has received funding from 60 billionaires, while “our campaign has received more campaign contributions from more Americans averaging $18.50 than any campaign in the history of our country at this point in time.” Sanders declined to point out in his speech that billionaires are still limited to a maximum individual campaign contribution of $2,800—and FEC records show he has also received contributions of that size.

Biden’s fundraising methods, Sanders argued, would render him beholden to special interests. “Does anyone seriously believe that a president backed by the corporate world is going to bring about the changes in this country that working families and the middle class and lower income people desperately need?” he said.

Sanders’ grassroots support has put him in the unique position of being able to rail against these fundraising practices as part of his platform. Nearly every candidate — including Biden — began the race eschewing super PACs, which cannot coordinate with the campaigns but can spend unlimited amounts. But that stance eventually collided with the reality that it is hard to raise money while competing in a crowded field that until recently included two self-funding billionaires. Even Massachusetts Senator Elizabeth Warren, who exited the race Thursday, reversed a campaign pledge and did not disavow a super PAC when one formed to support her as she struggled to gain traction.

Sanders’ pitch is clearly still resonating with the grassroots movement. By the end of the day on Wednesday, his campaign had raised $5.5 million.

But for the first time in the race that day, Biden announced higher numbers.

–With reporting by Lissandra Villa/Washington

Write to Alana Abramson at Alana.Abramson@time.com.

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