Donald Trump swept into the White House on a promise to run the government like a business and stock his administration with titans of industry.

The partnership hasn’t worked out.

Just over a year into Trump’s presidency, those titans are leaving, driven out by a chief executive who doesn’t want to hear no, doesn’t trust anyone but himself and can’t stand to share the spotlight, even with those he once hailed as “the best people” on earth for these jobs.

Trump humiliated Secretary of State Rex Tillerson—the former chief executive of oil industry giant ExxonMobil, whom he once described as “the embodiment of the American dream”—firing him by tweet. He repeatedly rejected the advice of National Economic Council Director Gary Cohn, driving the former president of Wall Street powerhouse Goldman Sachs nuts with his stubborn insistence on tariffs and hastening Cohn’s exit.

And he went ice cold on Commerce Secretary Wilbur Ross, reportedly telling the Wall Street legend that his understanding of trade was “terrible,” as West Wing aides leaked stories about Ross dozing off in meetings. Remember those CEO councils Trump initially set up to get advice from America’s top executives? They shut down in August.

Trump’s penchant for publicly and privately torturing powerful leaders in his administration extends to military brass. National security adviser H.R. McMaster is likely on the way out, with chief of staff John Kelly, a retired four-star general, possibly to follow. But it is Trump’s break with his Masters of the Universe that undercuts most clearly a central premise of his appeal as a candidate: He knew what it took to be successful, and he would hire people in his own image. The breakup, say White House officials, outside experts and even the president’s close friends, was inevitable.

Trump for decades ran a private real-estate and branding empire in which he was the only star. He ran a personality-driven campaign in which he said and did whatever he wanted, a strategy that resulted in stunning primary wins and a general election victory that few saw coming. And now Trump is even more fed up with strong-willed advisers who tell him he shouldn’t declare trade wars, or take it so easy on Russia, or decide on a whim to stage a summit with a nuclear-armed North Korean dictator who, it turns out, might never have extended the invite in the first place.

Trump is simply returning to who he’s always been, a one-man reality show who prefers to be surrounded by admirers who will praise and fawn over him and confirm that all his instincts are correct and brilliant and certain to succeed. The wonder is that anyone is surprised.

“There is an enormous literature on narcissistic leaders who rise to power because of grandiosity and an overwhelming amount of self-confidence,” Jeffrey Pfeffer, a professor of organizational behavior at Stanford’s business school, told me. “They don’t tend to get along well with other strong leaders. Trump doesn’t want anyone to stand in his way, and he certainly doesn’t want anyone who takes up any of his light or disagrees with him. He wants people who are willing to ingratiate themselves and flatter him. This is the way it was always going to be.”

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When Trump hired Cohn away from Goldman Sachs, the president couldn’t stop bragging about what a coup he pulled off by landing one of the top executives from the bluest of blue-chip Wall Street firms. Never mind that Trump’s final campaign ad treated Goldman as part of a global cabal out to destroy America.

“As my top economic adviser, Gary Cohn is going to put his talents as a highly successful businessman to work for the American people,” the president said after the hiring. In July of last year, Trump said in a Wall Street Journal interview that he was thinking of nominating Cohn to be the next chair of the Federal Reserve, possibly the most powerful finance job on the planet.

Then it all came crashing down. Cohn sharply and publicly criticized the president’s equivocating response to a white supremacist march in Charlottesville, Virginia, leading to a tense Oval Office meeting, resignation threats and the end of Cohn’s Fed chances.

Things improved as Cohn helped drive through Trump’s signature tax-cut bill. But then the White House agenda moved on to trade, and Cohn began to push back hard against Trump’s instincts to slap giant tariffs on imported steel and aluminum. Things came to a head in an Oval Office meeting in January at which Cohn told the president his tariffs would crush consumers and industries that rely on imported metals.

“These are the facts; where are your facts?” Cohn said to Ross and Trump’s trade adviser Peter Navarro, two of the administration’s leading protectionists, according to people familiar with the meeting. Trump rejected Cohn’s facts and pushed ahead with tariffs, announcing them in a rushed manner with no actual policy ready to roll out.

Days later, Cohn said he was leaving. And Trump slipped in a parting jab. “He may be a globalist, but I still like him,” the president told reporters. “He is seriously a globalist. There's no question.”

In Cohn’s place, Trump has hired former CNBC host and longtime Wall Street economist Larry Kudlow, who is also an avowed free trader and predicted during the campaign that Trump’s trade policies would tank the stock market. In early commentary, Kudlow has moved closer to Trump on trade, applauding the idea of cracking down on China. The former Reagan administration Office of Management and Budget official may yet prove to be just as aggressive as Cohn in resisting Trump’s mercantilist impulses. But the reason Trump hired Kudlow is mainly because he often says nice things about the president on television.

“Trump says he wants to be surrounded by a diversity of opinion, but he doesn’t really mean it,” Bill Galston, a former Clinton administration official now at the Brookings Institution, told me. “He certainly doesn’t want to be told that he’s wrong.”

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Trump’s treatment of Tillerson was even more brutal than his clashes with Cohn.

Stories began to leak last fall that the president strongly disliked the ExxonMobil CEO, who had different ideas on dealing with Iran, Russia and North Korea. Tillerson, accustomed to being the unquestioned boss himself (after all, he had led a 75,300-employee corporation for 11 years), chafed at Trump’s unwillingness to listen to his ideas or keep him involved in top diplomatic priorities. It was as if Trump was ignoring the very attribute that observers said made Tillerson appealing in the first place: He had negotiated with many key world leaders already—and succeeded at it.

In late September, after Tillerson said he was working on a dialogue with North Korea about its weapons program, Trump immediately took to Twitter to tell the world his secretary of state shouldn’t bother. “I told Rex Tillerson, our wonderful Secretary of State, that he is wasting his time trying to negotiate with Little Rocket Man,” Trump tweeted, referring to North Korean dictator Kim Jong Un.

Shortly after this clash, reports emerged that at a July 20th meeting at the Pentagon, Tillerson referred to the president as a “fucking moron.” The secretary of state never denied the remark. He was then left twisting for months amid reports that he would soon be ousted.

The relationship cratered for good in recent days. While traveling in Africa, Tillerson said the U.S. and North Korea were “a long way” from direct negotiations on the nuclear program. A day later, Trump announced he would hold a summit with the North Korean leader and Tillerson admitted he had no idea the announcement was coming.

On March 13, with Tillerson just returning from Africa, Trump fired the secretary of state by tweet, announcing he would be replaced by CIA Director Mike Pompeo. He then also fired Tillerson’s chief spokesman for denying the White House line that Tillerson knew about the firing plans in advance. Trump’s pledge of running the nation like a business had totally gone off the rails.

“No board of directors at any big company would ever permit this type of treatment or this level of chaos,” says Pfeffer.

Following the split with Tillerson and Cohn, some officials inside the administration, on Capitol Hill and in corporate America increasingly fear that the president is entering a period in which he will cast aside any strong advisers—whether top executives or senior military officials—who disagree with him while increasingly making rash decisions on his own.

And they say his early hiring of former top executives with strong personalities never really worked because Trump didn’t care very much about what they had to say and didn’t want them taking high-profile roles.

“You never really could convince him of anything, and he doesn’t really listen to anyone but himself,” one senior White House official told me recently. “You need people around to make these alternate cases, but I don’t think he really wants that.”

Trump’s friends and defenders don’t really deny that the president is moving into a new phase of his presidency, one in which he will naturally be less inclined to rely on executives who have subject-matter expertise, like Cohn or Tillerson. The president is growing in confidence, these people say, and increasingly believes he is best served following his own instincts rather than relying on the savvy guidance of former top executives.

“I was not surprised that there have been a number of personnel changes in the White House beginning with the first year and continuing,” Christopher Ruddy, the chief executive of Newsmax Media and a Trump confidant, told me. “Understandably, the president's been going through an adjustment period after he left business life and went into political life. In politics, he started out with people having great credentials but discovered that track record is a better criteria.”

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The question now is what the White House will look like once all the business titans are gone.

The biggest fear in the economic world is that Trump will no longer have any real constraints on his desire to impose major tariffs both on U.S. allies and on sometime-adversaries like China.

Cohn managed to get carve-outs for allies Canada and Mexico in the recently announced steel and aluminum tariffs. But once he’s gone, Trump may feel free to be Trump.

Treasury Secretary Steven Mnuchin, a former Goldman banker and movie producer, comes out of the business world and is generally in favor of free trade. But he’s viewed both inside the White House and outside as someone very disinclined to buck the president, privately or publicly.

With Cohn gone, the U.S. is now at greater risk of trade wars and the possible end of the North American Free Trade agreement, a development most economists believe would be catastrophic.

“I think we are already marching down that path, and it’s not at all clear what will restrain him,” Galston told me. “He is under the illusion that trade wars are easy to win, and there is no historical evidence to support that. And my fear is that rather than back down, his inclination will be to plunge forward and double down in the face of adversity.”

The other major risk is that the exodus of business minds spreads to military and national security advisers and anyone else in the president’s orbit who dares to express a contrary opinion or urge caution to a chief executive who believes his gut instincts turned him into the one of the most successful people in the world.

“I think all of these types of people will be gone soon, and all for the exact same reason,” says Pfeffer. “Trump has gotten to where he is by basically being who he is, and if you are a strong-minded person yourself and believe you have something substantial to contribute, you don’t want to stick around and keep getting run over by the boss.”

Ayanna Alexander contributed to this report.