Hillary Clinton says Donald Trump’s ongoing attack on a U.S. judge of Mexican heritage, who is overseeing the Trump University case, is proof he’s unfit to be president.

“He’s trying to demean and defame a federal judge who was a very accomplished federal prosecutor,” Clinton told MSNBC’s Rachel Maddow in an interview that aired Monday night. “I imagine he’ll move on to women judges, because he’s been insulting women so regularly, or maybe a judge with a disability, or perhaps one who was a former POW, or African-American.”

The presumptive Republican nominee is facing intense criticism from all sides for insisting that U.S. District Court Judge Gonzalo Curiel, an American citizen who was born in Indiana, should recuse himself from a lawsuit involving Trump University because he’s the son of Mexican immigrants. In a Friday interview with CNN’s Jake Tapper, Trump insisted that the judge had a conflict of interest.

“I’m building a wall,” Trump said in the interview, which aired in full on Sunday. “He’s a Mexican.”

On Monday, the Clinton campaign released an ad highlighting the Republican backlash to those comments.

.@realdonaldtrump’s bigoted comments about a Latino judge are so disgusting, even other Republicans are offended.https://t.co/3CEBq2jsDh — Hillary Clinton (@HillaryClinton) June 6, 2016

“This is dangerous nonsense that undermines the rule of law, that makes him appear to be someone who has no respect for fellow Americans,” Clinton told Maddow. “And I think it is yet more evidence why this man is dangerous and divisive and disqualified from being president.”

Clinton, who amassed enough delegates Monday to become the presumptive Democratic nominee, demurred when asked whether she thinks Trump himself is racist. But she echoed conservative commenters, including Erick Erickson and MSNBC’s Joe Scarborough, in labeling Trump’s comments as “racist.”

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“I don’t know what’s in his heart, but I know what he’s saying with respect to the judge, that’s a racist attack,” she said. “I don’t know what else you could call these attacks other than racist, other than prejudice, other than bigoted. It’s just plain wrong, and certainly wrong coming from someone who is vying to become president of the United States.”

According to the New York Times, Republican National Committee Chairman Reince Priebus has held recent discussions with Trump about his attacks on the judge. But during a conference call with his campaign surrogates on Monday, Bloomberg Politics reported that the brash real estate mogul ordered them to intensify their criticism of the judge’s credibility and, as Bloomberg put it, “impugn reporters as racists.”

Trump himself, though, appeared to tone done his rhetoric in an interview with Fox News’ Bill O’Reilly on Monday night.

“I don’t care if the judge is Mexican or not,” Trump said. “I’m going to do great with the Mexican people because I provide jobs. So I don’t care about Mexican. But we’re being treated very unfairly.”

Earlier in the show, O’Reilly argued that Curiel should recuse himself from the Trump case.

“Not because he did anything wrong — he didn’t — but to eliminate any doubt as to the motivation in court rulings,” O’Reilly said.

An hour later, O’Reilly’s colleague, Megyn Kelly, blasted “pundits” calling for the judge to step down.

“That is not the way our system works,” Kelly said. “Any litigant who moved to disqualify a judge based on his heritage would actually sanctioned — punished — by a court, and it’s happened in the past. Rightfully.”

Meanwhile, South Carolina Sen. Lindsey Graham urged fellow Republicans who are supporting Trump to rescind their endorsements.

“If anybody was looking for an off-ramp,” Graham told the Times, “this is probably it.”