A group of women progressives who back Sen. Elizabeth Warren has formed Persist PAC, a super PAC airing pro-Warren ads starting Wednesday in an effort to boost her performance ahead of Saturday's crucial Nevada caucuses, a spokesman told Axios.Why it matters: Warren has spoken adamantly against the influence of unlimited spending and dark money in politics. But these supporters have concluded that before Warren can reform the system, she must win under the rules that exist — and that whether she likes it or not, their uncoordinated help may be needed to keep her viable through this weekend's contest and into South Carolina and Super Tuesday.She's been losing ground as progressives have consolidated around Sen. Bernie Sanders, and she risks running out of money and momentum if she can't break out.The competition for Democrats' attention and votes has only gotten more difficult with billionaire Michael Bloomberg's self-funded run and rise in the polls.Warren placed third in Iowa and fourth in New Hampshire. Polling now shows her in third in Nevada days before the caucuses but in striking distance of second, while in national polls, billionaire Mike Bloomberg has surpassed her.Persist PAC's board includes four women in progressive politics who have worked in the labor, civil liberties and reproductive rights movements: Denise Feriozzi, Kristine Kippins, Karin Johanson and Kim Rogers.The 30-second ad, "Persist," will run in Nevada on broadcast as well as cable and digital platforms.It features images of Warren with former President Obama, with whom she worked to establish the Consumer Financial Protection Bureau; women and children; protesters' hands with "stop Kavanaugh" scribbled in pen; and President Trump. "When you don't grow up rich, you learn how to work," a female narrator says. "When you take on Wall Street, you know how to fight. . . she'll take him on and win."Spokesman Joshua Karp said the ad buy exceeds $1 million. He declined to detail the group's budget or identify sources of funding. "Senator Warren is the best candidate to take on Donald Trump and win, and we're going to ensure primary voters and caucus-goers hear her message," he told Axios.Flashback: Warren told her rivals during the Feb. 7 Democratic presidential debate in New Hampshire that "everyone on this stage except Amy [Klobuchar] and me is either a billionaire or is receiving help from PACs that can do unlimited spending," and if the others meant what they said about wanting to reduce unlimited spending and special interests they should "put your money where your mouth is and say no to the PACs."What they're saying:"Senator Warren’s position hasn’t changed. Since day one of this campaign, she has made clear that she thinks all of the candidates should lock arms together and say we don’t want super PACS and billionaires to be deciding our Democratic nominee."Warren's campaign tells AxiosFor the record: Klobuchar is also now getting some late uncoordinated help from a super PAC. Kitchen Table Conversations, a new political action committee supporting the Minnesota senator, filed with the FEC last Friday. Its first ad focuses on how her being kicked out of the hospital 24 hours after giving birth fueled a career in politics.Go deeper: Elizabeth Warren on the issues, in under 500 words