Donald Trump gets off his plane to speak at a rally on June 1 in Sacramento, Calif. (Jae C. Hong/AP)

Under a deluge of criticism from fellow Republicans that peaked on Tuesday, Donald Trump said that he intends to stop talking about a Latino federal judge he has repeatedly admonished on the basis of his ethnicity and that his words were “misconstrued.” He did not apologize for his remarks.

Trump’s new position came only minutes after Sen. Mark Kirk (Ill.) became the first vulnerable Republican senator to abandon support for the real estate mogul and several hours after House Speaker Paul D. Ryan (Wis.) said Trump’s attack on the judge was “the textbook definition of a racist comment.”

In a lengthy written statement issued after an uncharacteristically quiet day on social media, the presumptive GOP presidential nominee said that his repeated comments about U.S. District Judge Gonzalo Curiel were “misconstrued as a categorical attack against people of Mexican heritage.”

Trump said he does “not feel that one’s heritage makes them incapable of being impartial.” But he reiterated that he believes he has been treated unfairly by Curiel in two fraud cases against his defunct Trump University real estate seminar business and is therefore “justified in questioning whether I am receiving a fair trial.”

He concluded: “While this lawsuit should have been dismissed, it is now scheduled for trial in November. I do not intend to comment on this matter any further.”

Donald Trump's latest attack on the "Mexican" judge overseeing his Trump University case has left his surrogates scrambling to defend his remarks. Here are some of their attempts at defending him. (Monica Akhtar/The Washington Post)

In an interview with Fox News Channel that was broadcast Tuesday night, Trump said Republicans who were upset by his comments about Curiel should “get over it, ideally.” In a Tuesday night speech celebrating his presumptive nomination at the official end of primary season, Trump sought to push beyond the controversy, avoiding the matter altogether and instead striking a confident tone as he vowed to charge forward to the general election.

Trump’s sustained ethnic attacks on Curiel had quickly become a litmus test and near-existential crisis for the Republican Party, which is struggling to balance a need for minority support with Trump’s racially charged campaign. The episode also stretched the limits of Trump’s fraying relations with many of the people who will officially nominate him in Cleveland in six weeks: Their standard-bearer had suddenly forced them to choose between being disloyal to the party and backing a candidate who attacks a judge’s ethnicity as part of a petty personal feud.

While most lawmakers twisted and contorted themselves, GOP strategists, pundits and others in the anti-Trump camp hardened their opposition and revived talk of trying to derail him. Some, such as the blogger and pundit Erick Erickson, cast the episode in stark moral terms, arguing that no conservative could in good conscience support Trump.

“If you believe Trump’s comments are racist, you have an obligation to publicly reject him, not just say you disagree,” Erickson wrote Tuesday. “Shame on you if you do not.”

Trump first lambasted Curiel months ago when he was part of a crowded primary field. But after clinching the nomination, he revived the assault in late May at a rally in San Diego, going on an extended 11-minute monologue about the case and mentioning that the judge “happens to be, we believe, Mexican.” Curiel was born in Indiana to parents who emigrated from Mexico in the 1920s.

In media interviews in following days, Trump continued to harangue Curiel in more explicit terms. He told the Wall Street Journal that Curiel’s Mexican heritage presented an “absolute conflict” given that the mogul wants to build a wall along the U.S.-Mexico border.

“I’m building a wall,” Trump said. “It’s an inherent conflict of interest.”

The backlash from within the Republican Party gained force and quickly overshadowed other messages GOP leaders were trying to push. Moreover, Tuesday marked the official end of the GOP primary season — a moment many Republicans had hoped would mark an end to any serious intraparty skirmishing.

Ryan, who went to the Anacostia neighborhood of Southeast Washington on Tuesday morning to lay out a Republican anti-poverty agenda, was questioned repeatedly by reporters about Trump.

While the House speaker criticized Trump for his “racist comment,” he said he would continue to back the presumptive nominee.

“It’s absolutely unacceptable,” Ryan said. “But do I think Hillary Clinton is the answer? No, I do not.”

Other Republicans took a stronger position against Trump. Kirk, who is facing a challenging reelection campaign in a heavily Democratic state, said Trump’s remarks cemented his decision not to back him.

“While I oppose the Democratic nominee, Donald Trump’s latest statements, in context with past attacks on Hispanics, women and the disabled like me, make it certain that I cannot and will not support my party’s nominee for president regardless of the political impact on my candidacy or the Republican Party,” Kirk said in a statement. The senator suffered a stroke in 2012 and now often uses a wheelchair.

About a month ago, Kirk had described Trump — who won the Illinois primary in March — as a “net benefit” to his candidacy who was luring many new Republican voters to the polls.

Shortly before Trump issued his statement, Senate Majority Leader Mitch McConnell (R-Ky.), a Trump supporter, said it was “time to quit attacking various people you competed with or various minority groups in the country and get on message.” McConnell said Trump “has an opportunity to do that; this election is eminently winnable.”

“I hope that’s what he’ll do,” McConnell added. “We’re all anxious to hear what he’ll say next.”

Many Republicans continued to occupy a gray area between denouncing Trump and warmly supporting him, highlighting the angst many Republicans feel about the election,

“They’re racially toxic, and he needs to get on to the general election, and we need to win,” Sen. Tim Scott (S.C.), the only black Republican senator, said of Trump’s remarks.

Asked whether Republicans should rescind their endorsements of Trump, Scott offered a flat “no” and said he would back Trump.

Sen. Lindsey O. Graham (R-S.C.), a former 2016 presidential candidate who has refused to endorse Trump, said, “I’m not going around telling people: ‘Don’t endorse Trump.’ ”

Graham rejected the idea that Republicans could pull back their endorsements and deny Trump the nomination.

“I don’t see that as a viable alternate,” he said. “I don’t see a third-party challenge as a viable alternative.”

Sen. Jeff Flake (R-Ariz.), who has said he cannot back Trump right now, raised the possibility that Trump could face a revolt at next month’s Republican National Convention in Cleveland as a result of his racial rhetoric. Such a scenario he said, is “certainly more likely now than it was last week.”

Even beyond the halls of Congress, the anger with Trump could be felt. In Iowa, state Sen. David Johnson announced that he was suspending his Republican Party membership because of Trump’s “racist remarks and judicial jihad.”

Democratic leaders vowed to exact a toll on both Trump and down-ballot Republicans. They aggressively sought to tie Republicans in competitive states and congressional districts to the real estate magnate.

“The Donald Trump-House Republican ticket will hit them where it hurts: in the suburbs, with female, nonwhite, well-educated and independent voters,” said Rep. Ben Ray Lujan (N.M.), the chairman of the Democratic Congressional Campaign Committee.

Sen. Jeff Sessions (R-Ala.), who was the first senator to endorse Trump, said: “I do think it’s important that the campaign put its full focus on this campaign, the issues of the campaign, the vulnerabilities of Hillary Clinton, and try to avoid distractions and issues unrelated to what the American people are really concerned about.”

As recently as Monday, Trump was steadfast in defending his ethnicity-based criticism of Curiel and gave every indication that he intended to push ahead — causing turmoil and infighting within his campaign. In a conference call Monday, the real estate mogul told surrogates to step up their attacks on Curiel as biased and on reporters as racists, overriding a directive from his own staff distributed over the weekend, according to reports.

There were numerous efforts in recent days to urge Trump and his senior advisers to back off, including from major GOP donors and Republican National Committee Chairman Reince Priebus.

Curiel, who has declined to comment on Trump’s attacks, is overseeing two class-action lawsuits against Trump University in San Diego. Last week, as part of court proceedings, Curiel ordered the release of embarrassing internal documents that revealed Trump University’s predatory marketing practices. Staff members of the business were instructed to push customers to purchase expensive follow-up courses, often well beyond their means, with promises of success and trade secrets.

The Trump campaign and its surrogates have regularly pointed to Curiel’s membership in the San Diego La Raza Lawyers Association — an organization for Hispanic lawyers — to erroneously suggest that Curiel has participated in political activities against Trump. They appear to have conflated the lawyers group with the National Council of La Raza; the two groups are separate.

In his statement on Tuesday, Trump again seemed to allude to a potential association while continuing to suggest that Curiel’s Mexican heritage may have affected the judge’s decisions.

“Due to what I believe are unfair and mistaken rulings in this case and the Judge’s reported associations with certain professional organizations, questions were raised regarding the Obama appointed Judge’s impartiality,” Trump said in the statement. “It is a fair question. I hope it is not the case.”

Jose A. DelReal and David Weigel contributed to this report.