(CNN)Republican Party establishment figures are beginning to go public with their concerns about Donald Trump's race-based criticisms of the federal judge overseeing the Trump University lawsuit, even as the presumptive GOP nominee urges supporters to up the ante.
Top Republicans knock Trump over criticism of judge
U.S. District Judge Gonzalo Curiel's Mexican heritage has become a fixation for the GOP's presumptive nominee, who has repeatedly questioned the Indiana-born Curiel's impartiality -- often in stark terms.
Now, as worries mount that Trump's words could weigh down other Republicans in November, more high-profile elected officials and party leaders are speaking out. Here's what some of the biggest names are saying:
Ryan ended his waiting game and endorsed Trump on Thursday. One day later, the speaker was on the radio in his home state of Wisconsin bashing the presumptive nominee:
"Look, the comment about the judge, just was out of left field for my mind," Ryan told WISN in Milwaukee, nearly a week after Trump first criticized Curiel. "It's reasoning I don't relate to; I completely disagree with the thinking behind that."
"So (Trump) clearly says and does things I don't agree with and I've had to speak up from time to time when that has occurred and I'll continue to do that if that's necessary -- I hope it's not," Ryan added.
Among the most vocal Never-Trumpers, Sasse delivered a stinging condemnation Monday:
"Public Service Announcement: Saying someone can't do a specific job because of his or her race is the literal definition of "racism," he tweeted.
Cruz, a vanquished primary rival of Trump's, on Monday afternoon joined the chorus of concerned Republicans, saying, "Of course it's inappropriate to attack a federal judge's race or ethnicity.
"You'll have to ask Donald why he says the thing he does," he said. "I'm not going to try to explain it."
Rubio's long drift toward Trump seemed to stall on Monday, when he repeatedly criticized Trump.
"When I was running for president, I told everyone that this is what would happen," Rubio told CNN. "That we would continue to be faced with this very difficult choice, as we are, as many of us have been, between Hillary Clinton and Donald. This is not where I wanted us to be."
Earlier, he addressed the comments in Orlando: "I continue to have strong disagreements with (Trump) on a bunch of issues and I do not agree with and quite frankly I'm very disturbed by the way he keeps referring to this judge -- an American -- born Indiana who he continues to raise issues about and I hope he'll stop doing that."
The Kentucky senator endorsed Trump in early May, but is now warning that the billionaire businessman could alienate a generation of voters with his attacks on Curiel:
"This is a man who was born in Indiana," McConnell said on NBC's "Meet the Press." "All of us came here from somewhere else. Almost all Americans are either near-term immigrants like my wife, who came here at age 8 not speaking a word of English, or the rest of us whose ancestors were risk-takers who came here and made this country great. That's an important part of what makes America work."
Carson, who has emerged as a Trump supporter and emissary for the campaign, released the following statement via business manager Armstrong Williams: "Every human being is an individual first rather than a member of an identity group. The moment we forget that is the moment we enter into a phase of moral descent."
Schwarzenegger in 2006 appointed Curiel to his first judicial post, as a Superior Court judge. On Monday the action star-turned-politician -- and Trump's successor heading "Celebrity Apprentice" -- tweeted his dismay about Curiel's treatment by the presumptive Republican nominee, harkening back to the judge's days as a federal prosecutor.
"Judge Curiel is an American hero who stood up to the Mexican cartels. I was proud to appoint him when I was Gov."
Trump's former GOP primary rival has been mostly quiet since leaving the race after the Indiana primary. But on Monday he, too, dropped a pair of critical tweets, first condemning Trump's comments, then asking for an apology:
"Attacking judges based on their race &/or religion is another tactic that divides our country. More importantly, it is flat out wrong," he said, adding: "@RealDonaldTrump should apologize to Judge Curiel & try to unite this country. #TwoPaths"
Facing a tough general election challenge from New Hampshire Gov. Maggie Hassan, Ayotte has said she will "support" Trump, but has no plans to endorse. On Monday, she released a more easily-parsed response to Trump's remarks on Curiel: "His comments are offensive and wrong, and he should retract them."
Scott, the only African-American Republican in the Senate, told CNN Trump's criticisms are "racially toxic."
Corker has been among highest-profile elected officials to speak favorably about Trump. Though he hasn't offered an outright rebuke, this weekend the Tennessee senator did suggest the current path was a dangerous one.
"I think that he's going to have to change," Corker said on ABC's "This Week." "I'm not talking about him necessarily changing his views, but I think that he's moving into a different phase, he's talking to the right people."
Another vocal backer, Gingrich has emerged as one of the favorites to be chosen as Trump's running mate. But in an interview with The Washington Post published this weekend, he delivered a stern judgment:
"I don't know what Trump's reasoning was, and I don't care," Gingrich said in an email. "His description of the judge in terms of his parentage is completely unacceptable."
Collins, like many of her GOP colleagues, has been mostly mum on Trump, refusing to say if she'll vote for him or a third party candidate. But the Maine Republican told CNN Monday Trump's recent comments were "very troubling," and expressed concern they could "undermine respect for the judicial system."
But she stopped short of calling them "racist."
"They seem to be prompted more out of anger than the rulings that this judge has made. I think they are inappropriate regardless, she said. "After all, there are plenty of people who are white who Donald Trump has attacked. His personal insults, which must stop, seem to run the gamut."
Michael Reagan, son of Republican President Ronald Reagan, said his father -- iconic in GOP circles -- wouldn't vote for Trump if he was alive today.
"This most likely would be the 1st time if my father was alive that he would not support the nominee of the GOP @Reince @newsmax," he tweeted.