Pete Buttigieg and Elizabeth Warren sparred on the debate stage Thursday night over fundraising, with the South Bend, Ind., mayor telling Warren “this is the problem with issuing purity tests you cannot yourself pass” after she accused him of catering to wealthy donors.“The mayor just recently had a fundraiser that was held in a wine cave full of crystals and served $900 a bottle wine — think about who comes to that,” Warren stated, referencing a private donor dinner in Napa Valley that Buttigieg held Sunday.“He had promised that every fundraiser that he would do would be open door, but this was one closed door,” Warren argued. “We made the decision many years ago that rich people in smoke-filled rooms would not pick the next president of the United States. Billionaires in wine caves should not pick the next president of the United States.”Buttigieg responded by pointing out Warren was far wealthier than him. “According to Forbes magazine, I am literally the only person on this stage who is not a millionaire or a billionaire,” he said. “This is important — this is the problem with issuing purity tests you cannot yourself pass.”Buttigieg argued that “if I pledge never to be in the company of a progressive Democratic donor, I couldn’t be up here.”“Senator, your net worth is 100 times mine,” he said, asking Warren if a max donation from a wealthy individual “would that pollute my campaign?”“I would be glad to have that support,” Buttigieg argued. “We need the support from everybody who is committed to helping us beat Donald Trump.”After Warren replied “I do not sell access to my time,” saying “if you want to donate to me that’s fine, but don’t come around later expecting to be named ambassador, because that’s what goes on in these high-dollar fundraisers,” Buttigieg challenged Warren using holdover funds from past campaigning, including donations from wealthy donors.“Senator, your presidential campaign right now, as we speak, is funded in part by money you transferred, having raised it at those exact same big-ticket fundraisers you now denounce,” he said. “Did it corrupt you, Senator? Of course not . . . these purity tests shrink the stakes of the most important election upon us.”Buttigieg and Warren have clashed on the debate floor before, with Buttigieg criticizing Warren for her comments on Medicare for All in October. In November, as the South Bend mayor surged in the Iowa polls, Buttigieg told Showtime’s The Circus “I think this is getting to be a two-way” race between himself and Warren.