It was perhaps the starkest divide between the front-runners at Thursday’s Democratic debate: the candidates who attend private fundraisers and those who reject them.

On one side are former Vice President Joe Biden and Mayor Pete Buttigieg. They keep their campaigns running, in part, thanks to “bundlers” who organize their colleagues, friends, and family to each contribute up to $2,800, the maximum allowed by law.

If you can “chip in 10 bucks, that's great and if you can drop $1,000 without blinking, that's great, too. We need everybody's help in this fight,” Buttigieg said at the debate in Los Angeles.

View photos Pete Buttigieg and Joe Biden found themselves allied on the question of private fundraisers during Thursday's debate. (Photo by Justin Sullivan/Getty Images) More

On the other side are Senators Elizabeth Warren and Bernie Sanders who have rejected money from wealthy donors, and instead focused on small-dollar donations. “We made the decision many years ago that rich people in smoke-filled rooms would not pick the next president of the United States,” Warren said at the debate.

A flash point was over a recent Buttigieg fundraiser held in a now-infamous Napa Valley “wine cave” owned by a billionaire couple Kathryn and Craig Hall.

Here are some photos of the Buttigieg fundraiser in Napa -- with the famous wine cave and the chandelier with 1,500 Swarovski crystals -- that @BrianSlodysko wrote about.https://t.co/0sprQ3aDsy pic.twitter.com/3waO6jO93L — Teddy Schleifer (@teddyschleifer) December 16, 2019

A story about the event noted that the Hall wine caves “boast a chandelier with 1,500 Swarovski crystals, an onyx banquet table to reflect its luminescence and bottles of cabernet sauvignon that sell for as much as $900.”

The Halls are an example of the many rich progressive Democrats who are often a key fixture on the campaign trail. According to a profile of the couple, the Halls became wealthy in Texas through a variety of business and real estate ventures. Kathryn once ran for mayor of Dallas and served as the U.S. ambassador to Austria during the Clinton administration. More recently, they have focused on running their winery.

At the debate, Sanders commented on how much time his rivals spend with billionaires like the Halls. “My good friend, Joe, and he is a good friend, he's received contributions from 44 billionaires. Pete, on the other hand, he's trailing, Pete. You only got 39 billionaires contributing,” Sanders said.

How a Buttigieg fundraiser is different from a Biden fundraiser

Both the Buttigieg and Biden campaigns allow a “pool” reporter to cover at least some of these private events and report on who attended and what was said.

Buttigieg’s events are often filled with bold-faced names. He recently raised money from Vogue’s editor-in-chief Anna Wintour in New York and from environmental activist Laurie David in West Hollywood. “I particularly like the way the Mayor describes America’s crisis of belonging in this vexed and vexing time,” Wintour said at her fundraiser.

View photos Anna Wintour has been editor-in-chief of Vogue since 1988. (Photo by Lia Toby/BFC/Getty Images) More

Buttigieg also reportedly recently raised money from Reed Hastings, the co-founder of Netflix, as well as family members of Google co-founder Sergey Brin, former Google CEO Eric Schmidt, and Facebook COO Sheryl Sandberg. Another event earlier this year was reportedly held at Gwyneth Paltrow’s house.

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