Donald Trump fired his controversial but loyal campaign manager on Monday, a move that underscored the doubts his party has had about the presumptive nominee’s ability to run a general election campaign against Hillary Clinton.

In a campaign that’s been engulfed in controversies of its own making, is sinking in the polls, struggling to unite the GOP, and lagging significantly behind in organization and fundraising, Trump’s surprising step appeared to be an admission to restless party members, leaders, and key donors of his failure to launch.

But whether axing Corey Lewandowski is symbolic of a true maturation on behalf of the campaign or simply a glossing over of flaws remains to be seen. And it’s unclear that the move will calm Republican nerves, as many party officials are already resigned to the notion that Trump cannot be tamed or controlled -- ultimately, he’s his own campaign manager.

Underscoring the uncertainty: There was no formal announcement of the new campaign manager or the unveiling of a new campaign strategy. Convention manager Paul Manafort, a veteran campaign hand with whom Lewandowski clashed, will take over the role while keeping his title of campaign chairman. The campaign is expected to hire additional staff, including communications aides.

Trump's campaign troubles were further highlighted Monday night, when newly released federal filings showed the candidate raised just $3.2 million in May, the month he became the presumptive nominee and the general election polls were close. His presidential campaign has only $1.3 million in cash, according to the report, which more closely resembles that of a congressional campaign. He has not yet run any ads. Clinton raised $26 million that same month and has $42 million on hand.

“Hopefully this is a pivot point that will allow the campaign to shift gears,” said GOP strategist Ryan Williams. “Improving the campaign is but one component. The candidate needs to improve himself by studying up on the issues and exhibiting self-discipline.”

Says one New Hampshire delegate: “I would think Corey might have been to blame but now we will see for sure. If [Trump] continues on the same path, then it wasn't just Corey."

Trump’s decision to fire Lewandowski, who has been with him since the beginning of his campaign, came after a weekend meeting with his children in which they pushed for the aide’s ouster, according to a source close to the campaign. Daughter Ivanka Trump has been seen as a driving force behind the effort. Her husband, Jared Kushner, who advises his father-in-law on policy, also clashed with Lewandowski, according to the source.

Lewandowski was let go on Monday morning after a campaign meeting and was escorted out of Trump Tower shortly afterward as part of an apparent dismissal protocol. The news came as a surprise to him, as he had spent the weekend traveling with Trump.

When asked during a lengthy appearance on CNN -- one in a round of television interviews he gave throughout the day -- why he was fired, Lewandowski said, "I don't know. I don't know the answer to that.”

He remained steadfast in his loyalty to Trump throughout the interviews in a way reminiscent of a new hire. “What I know is that what we've been able to achieve in this election cycle was historic,” he said. “I had a nice conversation with Mr. Trump and I said to him, 'It's been an honor and a privilege to be a part of this,' and I mean that from the bottom of my heart."

Lewandowski also indicated he’d like to remain involved. "If I could play a role in this campaign, whether it's formal or informal, that would be an honor for me to have,” he told NBC.

The former campaign manager remains a Trump delegate for New Hampshire and will be leading the delegation at the convention in Cleveland next month.

The hot-headed operative with an unconventional resume made an instant impression on Trump when they met at Trump Tower in December 2014.

“We hit it off, and if you don’t hit it off with your campaign manager, you have a problem,” Trump later told the Washington Post.

Once on the campaign, Lewandowski quickly consolidated his power, even at the expense of some longtime Trump aides, and acted as a gatekeeper to the candidate. He even traveled with Trump frequently — an unusual setup for a campaign manager, but one that afforded Lewandowski access and influence at all times.

Not that he was necessarily steering Trump’s messaging or strategy with a firm grip.

“He leaves me alone,” Trump told The New York Times last year, “but he knows when to make his presence felt.”

Still, Trump credited Lewandowski with a share of his success throughout the primaries. When the business mogul won the crucial New Hampshire primary on Lewandowski’s home turf, Trump singled him out among other aides and supporters. “Does Corey have a ground game or what?” Trump said in his victory remarks.

But Lewandowski’s inexperience and intensity would also test the limits of his boss’s loyalty.

He became the focus of public controversy in March, when Michelle Fields, then a reporter for Breitbart, accused Lewandowski of grabbing her arm and nearly pulling her to the ground as she tried to ask Trump a question at a campaign event.

“You are totally delusional,” Lewandowski tweeted at Fields on March 10. “I never touched you. As a matter of fact, I have never even met you.” Video from a security camera ultimately showed this to be false, and Palm Beach, Fla., police charged Lewandowski with battery. The state’s attorney ultimately decided not to move forward with prosecution, however.

Not two weeks later, video footage again documented physical aggression by Lewandowski as he grabbed a protester by the collar at a rally in Tucson, Ariz. After this incident, he expressed some remorse.

“When I see something that I think isn’t right, I think I have some kind of, for right or wrong, an obligation to fix it,” he told the Washington Post, whose reporter described Lewandowski’s eyes as welling with tears. “I thought [the protesters’ disruption] was wrong.”

“My job is not to do that,” he added. “And I need to stay focused on my job.”

And Trump determined that in spite of these missteps Lewandowski should keep his job, publicly defending his embattled aide.

“Folks, look, I'm a loyal person,” Trump insisted at a Wisconsin town-hall gathering in early April. “I'm going to be loyal to the country.”

Internally, however, Lewandowski’s role diminished. At the end of March, Trump hired the experienced GOP hand Paul Manafort to wrangle delegates and manage the convention when it looked like July’s gathering could be a contested fight for the nomination. But he in fact took over running the campaign, Lewandowski and Trump’s allies say now.

Lewandowski, for his part, was relegated to managing Trump’s travel and events schedule, a role that permitted him to remain on the road with the candidate — and perhaps enable his worst instincts. Lewandowski’s mantra was to “let Trump be Trump,” even at a crucial period when Republicans urged the celebrity businessman to moderate his tone and transition to the general election.

Instead, Trump’s campaign has gone off the rails. Republicans have panicked over his dismal polling and lack of direction; many fear it is now too late to correct course.

Nor is it clear that Lewandowski’s ouster will do the trick. Trump, more than anyone, has steered his own campaign — and while his decision to fire Lewandowski acknowledges that change is needed, whether Trump will ultimately change himself is an open question.

“We’re going to find out,” said one ally. “I really don’t know whether you can affect the substance of what he says.”

Surrogates insist that such shake-ups are par for the campaign course, and that Trump is positioning himself for the general election, even if such shifts and shake-ups don’t traditionally come this late in the game.

"Donald Trump is going to be Donald Trump,” says Boris Epshteyn, a New York based-Trump surrogate, arguing that the campaign changes illustrate the candidate’s ability to make tough management decisions. “[He got this far] by being himself and trusting his instincts, so you're not going to see him change."

Caitlin Huey-Burns is a national political reporter for RealClearPolitics. She can be reached at chueyburns@realclearpolitics.com. Follow her on Twitter @CHueyBurnsRCP.