The physical assault of Breitbart reporter Michelle Fields at a Donald Trump press conference in March was—in many ways—the logical product of a campaign in which the Republican candidate has made his contempt for journalists, the media, and women increasingly clear.

Less surprising still have been Trump’s reactions to the allegations: He has responded by doubling down on his claims the incident never happened, questioning Fields’ credibility, mocking her, and asking whether she could have already had or somehow have fabricated the bruises she claims resulted from the incident.

It should hardly be shocking that the accused rapist who once said, "Women. You have to treat them like shit," doesn’t believe a female reporter’s story, but for 16 conservative female journalists who penned a letter to Trump on Wednesday asking him to believe their fellow reporter, the candidate has apparently crossed a line.

Trump’s ham-fisted attempts to treat women like normal human beings has taken a toll on his support base.

“The photographs, audio, videos, and witness accounts documenting the treatment of Michelle Fields by Corey Lewandoswki, Donald Trump’s campaign manager, are inexcusable and unprofessional. Donald Trump should immediately remove Lewandowski from his campaign,” the letter, signed by Blaze TV’s Dana Loesch, Meghan McCain, and other women journalists said. “The Trump campaign has stated that Lewandowski will not be fired even if convicted, however unlike the Trump campaign, we believe in making a statement on the record to clearly highlight the difference between right and wrong.”

Trump has been pushing those boundaries since his campaign began, from his early comments that political commentator Megyn Kelly had blood coming out of “her wherever” to allegations his campaign manager was reportedly calling female journalists drunk late at night, to his recent attempt to hit on a Washington Post journalist. With Trump’s recent attacks targeting some of their own—conservative journalists—and the election quickly approaching, Republicans are beginning to see the damage that could be done if Trump’s inability to interact with women is put on the international stage when he goes against the most likely Democratic candidate: Hillary Clinton.

Though not as revolting as his violently misogynistic statements (his recent assertion that women should be punished for having abortions, for example) Trump’s ham-fisted attempts to treat women like normal human beings has taken a toll on his support base. He has repeatedly shown his inability to behave himself in a presidential manner around women, insulting the physical appearance of his only other female rival, Carly Fiorina. Many of his attacks on Clinton thus far have also centered on her appearance as well, rather than, you know, her actual policies.

Calling Clinton a dog or insulting the physical appearance of female counterparts may have seemed like a wacky side effect of Trump’s straight-talking rhetoric for Republicans at the beginning of his campaign, but as his candidacy gets closer and and closer to becoming a reality, voters must face the fact that Trump could soon be debating foreign policy with the current Secretary of State, armed only with misogyny schoolyard insults.

For many Republican voters, this prospect could be enough to push them towards a more reasonable candidate. Trump is now trailing further behind Clinton in general election polls and conservative New York Times columnist David Brooks even denounced Trump’s ‘commercial’ misogyny this week, saying he uses women as pawns against political opponents in his “uncontrolled” objectification.

“This is the world your daughters are going to grow up in,” he warned.

While the Republican party has passed regressive laws against women’s right to choose, fought expanded access to birth control, and thwarted attempts to make maternity leave more accessible to women, even the most conservative voters have a limit, and Trump might have just crossed it.