(CNN) For a moment, it seemed like a new Donald Trump was hitting the campaign trail.

After a week of being pummeled for his attacks on a federal judge overseeing a fraud case against his namesake training program, the presumptive Republican presidential nominee stood before the cameras Tuesday night to deliver an unusually conventional speech -- composed and seemingly sincere about his duty to lead the GOP.

"I understand the responsibility of carrying the mantle," he said. "And I will never, ever let you down."

Nervous Republicans who have been waiting for the impulsive, rabble-rousing candidate to show some restraint were relieved, hoping a more presidential Trump was about to emerge as he transitions to a one-on-one race with Hillary Clinton. But it quickly became clear Wednesday that such hopes might be misplaced when Trump insisted to Time magazine there was no change in strategy and that his speech -- unusual for its reliance on teleprompters -- was simply intended to mark a special moment.

The fallout from Trump's broadsides against U.S. District Court Judge Gonzalo Curiel, who Trump has said is biased because of his Mexican heritage, have marked a low point in the businessman's unlikely rise to the top of the GOP. House Speaker Paul Ryan, who only recently endorsed Trump, called the comments from his party's nominee "textbook" racism. Many Republicans in Congress are questioning their endorsement of Trump and there's rampant fear that his racially-charged rhetoric could doom downballot candidates and put the GOP's grip on the Senate -- and possibly the House -- at risk.

Trump's response to the crisis, described mostly by aides, advisers and donors who spoke without attribution to discuss the inner workings of the campaign, signals a candidate who plans to zig and zag during the fall campaign to keep his opponent guessing. It also provides insight into the people whose advice he accepts -- even grudgingly. That small club includes his daughter, Ivanka, son-in-law Jared, campaign manager Corey Lewandowski and adviser Paul Manafort along with others such as Republican National Committee Chairman Reince Priebus and New Jersey Gov. Chris Christie.

Perhaps most significantly, the episode underscores a fierce resistance inside Trump's orbit to mellowing the controversial personality that took the GOP by storm this spring.

'Speaks for himself'

"Donald Trump continues to talk about his message. There's nothing new there," Lewandowski told CNN. "Donald Trump speaks for himself. Anyone who reads into what Mr. Trump does, does so at their own peril. Mr. Trump's words are very clear and he speaks for himself."

Asked about Trump's shift in tone and whether it would allay concerns of Republicans opposed to Trump, Republican strategist John Weaver said that was unlikely.

"I guess if officials at the RNC or some Republican leaders want to believe in the tooth fairy then they're entitled to do that," said Weaver, who was John Kasich's chief strategist during his 2016 presidential run. "But you tell a man's character when there is no teleprompter."

"To suddenly believe that the tone Mr. Trump used last night is the tone that he will constantly use going forward is ludicrous," Weaver continued. "Give it a little bit of time and we'll be back to square one, which we've seen over the course of his career."

Indeed, there's no indication that the Trump campaign is undergoing a major overhaul. Time and again, Trump has set off firestorms that Republicans outside the campaign predicted would end his candidacy, and Trump has weathered all of them, winning the nomination and nearly 14 million votes along the way.

"As long as we can keep making his case, the others will eventually begin to see the light," said one senior Trump adviser. As for those who are openly criticizing Trump and fretting over his demeanor, the adviser offered a piece of advice: "Suck it up and move on."

Trump's longest-serving aides believe the billionaire's unscripted style is what attracted voters in the first place, and they have no intention of abandoning that playbook in a general election fight.

"You win the nomination and they want to change you," the adviser said. "As soon as you get somebody out of their comfort zone, then the public kind of goes, 'What's this?' You need to keep Trump in his comfort zone."

At the same time, sources tell CNN that Trump's more restrained tone Tuesday night -- as well as the statement he released attempting to quell the controversy over his comments on Curiel -- evolved from a series of recent conversations with top party officials including Priebus, Christie and Alabama Sen. Jeff Sessions. All of them hope to quiet worries within the party over Trump's unpredictable behavior and inability to stay on message as Clinton ramps up her campaign.

Trump took the lead in writing his speech for the Tuesday night event, sources said. But he also fielded suggestions from Ivanka, Christie, Sessions, and several senior staffers. They all urged Trump, in one way or another, to ratchet down his rhetoric in recent weeks, even as he insisted that he's getting a raw deal from the press.

Perhaps most important in Trump's tonal pivot this week, some said, was the strong, guiding hand of his campaign chairman and chief strategist Paul Manafort.

Earlier this week as Trump's comments about Curiel were being roundly denounced as racist and inappropriate, Manafort stepped in and urged Trump to stop fanning the flames of the controversy.

Growing pressure

That only added to the pressure on Trump to heed words of caution from leading GOP figures like Ryan, Senate Majority Leader Mitch McConnell, and Tennessee Sen. Bob Corker, who called Trump's comments about Curiel "wrong at every level" during a Tuesday interview with MSNBC.

"Manafort won," one source said, referring to the reports of an ongoing power struggle within the campaign between Manafort and Lewandowski, who has hued to a motto of "let Trump be Trump."

Some Trump allies and Republican Party loyalists alike continue to worry about the difficulty of predicting which Trump will emerge on a given day, particularly as they try to chart a coherent strategy for defeating Clinton.

"It's like Dr. Jekyll and Mr. Hyde," the source said.

Trump's impulsiveness and frequent provocations as he lurches from one controversial topic to the next have created some real problems within the campaign as they try to build out their skeletal infrastructure.

Several Republicans who have been approached by the campaign say the organization has struggled to hire even for some of the most basic functions -- like communications and advance. Several younger staffers who have been approached as potential hires tell CNN they worried their professional reputations would be at stake if they were associated with Trump's more inflammatory rhetoric.

As Trump continues to stir controversy, some donors don't want their names on checks that go to Trump effort. Some are very carefully navigating the different fundraising committees set up by the RNC to ensure that their money is earmarked solely to help the party and other Republican candidates running in 2016.

One senior Republican donor, who has been a leading fundraiser for the party for decades now, said there is a palpable reluctance among some traditionally "rock-solid" GOP donors to associate themselves with Trump. "We keep looking for that more presidential posture, then inevitably we see a reversion."

Staying on message is one concern, but recognizing the infrastructure and organization needed to run a winning general election campaign is another. This donor said it's already too late to put together a national organization and Trump is facing a money shortfall "in the hundreds of millions" compared to Clinton.

Asked if Trump's team realized that, the donor said, "either they know it or they don't have any understanding of what fundraising is all about."

Still, Trump's team can make up ground behind the $2,700 checks of party loyalists -- those that respect the party, respect Priebus, and despise Clinton -- if Trump is willing to put in the work. That means phone calls, which this donor said Trump has shown limited interest in doing. Trump, in general right now, "is a tough sell," the donor said.

But start arranging high-level, well crafted finance events/fundraisers, and the money will start to come in.

"Finances alone don't determine who wins, we know that. But they do make a major difference," the donor said.