Donald Trump arrives at the Republican National Committee headquarters in Washington on May 12, 2016. (Nicholas Kamm/AFP/Getty Images)

This post has been updated.

The head of Hispanic media relations for the Republican National Committee is leaving party headquarters to join a conservative group supporting GOP congressional candidates. She'll be replaced by a former top aide to Jeb Bush who spent much of the last year raising doubts about Donald Trump.

The shake-up comes a little more than a month before Trump is set to formally accept the Republican presidential nomination. His candidacy has thrived despite accusations that undocumented immigrants from Mexico are criminals and rapists and recent attacks on prominent Hispanic political and legal figures. Those comments run counter to attempts by the GOP in recent years to win back the support of minorities, especially Latino voters.

But those efforts have sputtered in the wake of Trump. That's why Ruth Guerra, who had served as Hispanic media director for the last several years, is departing to join the American Action Network, a conservative group helping elect GOP congressional candidates, according to multiple Republicans familiar with the plans.

The RNC announced Wednesday night that Guerra will be replaced by Helen Aguirre Ferre, a GOP operative and former Spanish-language conservative radio talk show host with deep roots in the Miami area. (Her father-in-law is Maurice Ferre, the first Hispanic mayor of Miami.)

The dichotomy of being a Republican paid to defend a candidate attacking Hispanics on a near-daily basis proved to be too much for Guerra, according to multiple Latino Democratic and Republican operatives familiar with her thinking. Despite differences in party affiliation, Latino Democratic and Republican aides in Washington are a tight-knit group, given that just a handful hold prominent positions.

"I'm so proud of her" for leaving, one Hispanic Republican said Wednesday night when told the news. "I don't know how she held on for this long."

Pablo Manriquez, until recently a top Hispanic media official with the Democratic National Committee, credited Guerra for helping build a "national infrastructure" designed to attract minority voters "that it's obvious Donald Trump has no intention of deploying in that way."

"Having been the Hispanic media director across the political divide from her, she was always much better at that role than I was. She was easily the top Hispanic television press operative I saw this cycle," he said. "It's a huge loss for the RNC."

Guerra did not return requests for comment on Wednesday night. News of her departure was first reported by The New York Times.

Aguirre Ferre is a former aide and close friend of Bush and his family. She prepped the former Florida governor for major speeches and presidential debates and served as his top Spanish-language surrogate. The former host of a radio program for Univision's national network of talk stations, she also was a top Hispanic affairs adviser to Mitt Romney's 2012 presidential campaign.

In a statement issued by the RNC, Aguirre Ferre said she's "eager to make the case to the Hispanic community why Republican ideas and values are the way forward for our country after eight years of an Obama agenda which has failed all Americans."

Despite that eagerness, she frequently expressed doubts about Trump in public during appearances on Spanish-language television programs and on Twitter — as recently as last month.

Appearing May 8 on Univision's "Al Punto," a Sunday public affairs program hosted by the network's popular anchor Jorge Ramos, she agreed with other panelists who said that a segment of the Republican Party would not unite around Trump.

"I think you're going to see a segment, Jorge, who won't be able to do it. Because they don't consider Trump to be a real conservative," she said in Spanish.

Aguirre Ferre also explained why she thought House Speaker Paul D. Ryan (R-Wis.) was withholding support from Trump.

"He has a particular function. And that is that he needs to ensure and guarantee that Republicans maintain the majority in the House of Representatives," she said. "And that's his principal task. For those who know Paul Ryan, they know he doesn't have much in common with Trump ideologically and in moral character, either."

She retweeted the show's tweet about her comments — but later deleted it.

More recently, Aguirre Ferre deleted at least one tweet critical of Trump, but a cached copy of the tweet from mid-May shows that it linked to a poll suggesting Miami-area Cuban Americans would leave the GOP if the businessman won the nomination.

During an appearance last August on Mega TV's "Ahora con Oscar Haza," she also criticized Trump for his "extremely offensive" attack on Bush's wife. Trump had retweeted an offensive comment about Columba Bush, who was born in Mexico.

Aguirre Ferre isn't the first political operative to shift from attacking an opponent at one point in a long campaign and later working for that same candidate. Operatives in both parties — including a handful this cycle — have pivoted before.

Late Wednesday, Aguirre Ferre said nothing about Trump in response to questions about her past criticisms.

"I look forward to the opportunity to continue to reach out to the Hispanic community to talk about how we can turn this crippling economy around, appoint Supreme Court Justices who will not legislate from the bench, replace Obamacare, improve national security and provide a better future with better jobs for our children and grandchildren," she said in an email. "Hillary Clinton offers a third term of the Obama administration and those policies have been a failure. We can’t afford another Clinton/Obama presidency."

Trump's candidacy found early support amid his calls to charge Mexico for the construction of a multibillion-dollar border wall and his claims that Mexico was sending criminals and rapists across the U.S. border illegally. In more recent days, Trump has alarmed party leaders and legal experts by attacking prominent Hispanics, including New Mexico's Republican Gov. Susana Martinez and Gonzalo P. Curiel, a U.S. district judge in California overseeing a legal challenge to his now-defunct Trump University.

His rhetoric has led to record-low approval ratings for Trump among Latino voters.

Guerra, a Texan of Mexican descent, was critical to the RNC's attempts to improve its outreach to minority voters in the wake of Romney's 2012 loss. Romney earned just 27 percent of the Hispanic vote — a historic low — in part after suggesting that many undocumented immigrants would "self-deport."

In May, Guerra appeared on "Al Punto" just before Trump cleared the field and clinched the nomination. She was there officially to talk about the GOP's outreach to millennials, but Ramos pressed her to defend and explain Trump's comments. Guerra declined to speak for Trump — as any RNC official would — noting that he had yet to clinch the nomination.

Alfonso Aguilar, a Hispanic conservative activist who knows Guerra and Aguirre Ferre, said Wednesday night that it will continue to be a challenge for any Latino Republican to defend Trump.

"You can have all the Helens you want, but if the candidate continues with his rhetoric and proposals, you're not going to win Latinos," he said. "There's a problem in terms of tone and policy. It's going to be tough for Helen — I don't know how you do it."