The statement followed a report in The Wall Street Journal that Mello once supported legislation “requiring women to look at ultrasound image of their fetus before receiving an abortion.” The liberal website Daily Kos withdrew its endorsement of Mello over the report.

On Thursday, Mello told The Huffington Post, however, that he “would never do anything to restrict access to reproductive health care,” if elected. Jane Kleeb, the chair of the Nebraska Democratic Party and board member of Our Revolution, a group that emerged out of the embers of the Sanders campaign, said in an interview that The Wall Street Journal and NARAL had “mischaracterized” Mello’s legislative record.

“Heath is a strong progressive Democrat, and he is pro-life, and you can be both things,” Kleeb said, adding: “What Heath did actually was stop a bill to make ultrasounds mandatory by getting Republicans in our legislature to agree to make them voluntary.”

Mello’s vow did not satisfy NARAL, however. “It’s not enough to issue a statement for political expediency when your record is full of anti-choice votes,” Ilyse Hogue, the organization’s president, said in a follow-up statement. “The Democratic Party’s support of any candidate who does not support the basic rights and freedoms of women is disappointing and politically stupid.”

That’s not the only controversy to divide the party in less than 24-hours. Sanders also drew backlash from Democrats after he told the Journal that he doesn’t know if Jon Ossoff, a Democratic candidate hoping to flip a conservative congressional district in Georgia, is a progressive in an article published on Wednesday. Sanders appeared to go even further in an interview with The Washington Post, saying bluntly: “He’s not a progressive.”

So, why isn’t Sanders convinced Ossoff, a candidate backed by progressive organizations like MoveOn.org and the Progressive Change Campaign Committee, and who raked in millions of dollars in part because he has captivated grassroots Democrats looking to send a message to Trump, is progressive?

Sanders allies argue that Ossoff has not elevated, or embraced, core economic issues that the senator champions, like reducing income equality. They also defended Sanders’ decision to campaign with Mello by stating that the senator is a champion of reproductive rights for women. (Sanders has received a 100% on Planned Parenthood Action Fund’s congressional scorecard.)

“I fully stand by Senator Sanders because he does champion women's reproductive rights and he has never wavered there,” said Lucy Flores, a board member for Our Revolution, which has also endorsed Mello.

Flores added that while she personally would not support any candidate who does not fundamentally support a woman's right to abortion “the fact that this one issue didn't disqualify his support of Mello just speaks to the complexity of what it means to be a progressive champion during a time when many within the Democratic Party are still trying to figure out what that means.”