WASHINGTON -- U.S. President Donald Trump once presided over a reality show in which a key cast member exited each week. The same thing seems to be happening in his White House.

Trump's West Wing has descended into a period of unparalleled tumult amid a wave of staff departures, yet the president insists it's a place of "no Chaos, only great Energy!" The latest to announce his exit is Gary Cohn, Trump's chief economic adviser, who had clashed with the boss over trade policy.

Cohn's departure has sparked internal fears of an even larger exodus, raising concerns in Washington of a coming "brain drain" around the president that will only make it more difficult for Trump to advance his already languishing policy agenda.

Multiple White House officials said the president has been pushing anxious aides to stay on the job.

"Everyone wants to work in the White House," Trump said during a news conference Tuesday. "They all want a piece of the Oval Office."

The reality is far different.

Vacancies abound in the West Wing and the broader Trump administration, with some jobs never filled and others subject to repeat openings. The position of White House communications director is soon to be empty again after the departure of its fourth occupant, Hope Hicks.

"They are left with vacancies atop of vacancies," said Kathryn Dunn-Tenpas of the Brookings Institution who tracks senior-level staff turnover. Her analysis shows the Trump departure rate has reached 40 per cent in just over a year.

"That kind of turnover creates a lot of disruption," she said, noting the loss of institutional knowledge and relationships with agencies and Congress. "You can't really leave those behind to your successor."

Turnover after a year in office is nothing new, but this administration has churned through staff at a dizzying pace, and allies are worried the situation could descend into a free-fall.

One White House official said there is concern about a potential "death spiral" in the West Wing, with each departure heightening the sense of frenzy and expediting the next.

Multiple aides who are considering departing, all speaking on condition of anonymity to discuss internal matters, said they didn't have a clue about whom the administration could find to fill their roles. They said their desire to be team players has kept them on the job longer than planned. Some said they were nearing a breaking point.

"You have situations where people are stretched to take on more than one job," said Martha Joynt Kumar, director of the White House Transition Project.

She cited the example of Johnny DeStefano, who oversees the White House offices of personnel, public liaison, political affairs and intergovernmental affairs. "Those are four positions that in most administrations are each headed by an assistant to the president or a deputy assistant," Kumar said.

The overlap between those qualified to work in the White House and those willing to take a job there has been shrinking too, according to White House officials and outside Trump allies concerned about the slow pace of hires.

Trump's mercurial decision-making practices, fears of being drawn into special counsel Robert Mueller's Russia investigation and a stalled legislative agenda are keeping top-flight talent on the outside.

"Most of all, President Trump hasn't demonstrated a scrap of loyalty to current and former staff, and everyone knows it," said Michael Steel, a former aide to onetime Gov. Jeb Bush, R-Fla., and ex-House Speaker John Boehner, R-Ohio.

Trump acknowledged that he is a tough boss, saying he enjoys watching his closest aides fight over policy.

"I like conflict," he said Tuesday.

Since his days on the campaign, Trump has frequently and loudly complained about the quality of his staff, eager to fault his aides for any mishaps rather than shouldering responsibility. His attacks on his staff have sharpened in recent weeks, and he has suggested to confidants that he has few people at his side he can count on, according to two people familiar with his thinking who were not authorized to discuss private conversations publicly.

Hicks' departure will leave a gaping hole in the president's inner circle. She served as both media gatekeeper and confidante.

A number of other aides have expressed worry about the legal implications -- and steep bills -- they could face if ensnared in Mueller's probe. It has had a chilling effect on an already sluggish White House hiring process, according to officials, and there is wide concern that working for Trump could negatively affect career prospects.

Meanwhile, hopes for significant governing achievements in the coming years, along the lines of the tax cuts passed in December, are growing fleeting, as Republicans face a daunting electoral environment this fall.

Morale has plunged among West Wing aides in recent weeks. Some point to the departure of staff secretary Rob Porter in mid-February as beginning the tailspin.

Porter was a popular figure, but his departure undid some of the progress made on streamlining the White House's chaotic policy process. Allegations of domestic violence against him stunned co-workers. A permanent replacement has yet to be named.

Moreover, chief of staff John Kelly's shifting explanations for how he handled the Porter matter -- including, in the eyes of some, outright lies -- damaged his reputation among staffers who had seen Kelly as a stabilizing force in a turbulent West Wing.

The administration has been understaffed from the onset, in part due to the president's refusal to consider hiring even the most qualified Republicans if they opposed him during the campaign, according to a White House official not authorized to speak publicly about personnel matters.

The White House did not immediately announce a replacement for Cohn, whose deputy, Jeremy Katz, left in January. Among those under consideration for Cohn's job are CNBC commentator Larry Kudlow and Office of Management and Budget Director Mick Mulvaney, according to a person familiar with the discussions.

In a riff Saturday at the Gridiron Dinner, an annual white-tie affair featuring journalists and officials, Trump engaged in a rare bout of self-deprecating humour, comparing the Oval Office job with his past career as the host of the reality-television show "The Apprentice."

"In one job I had to manage a cutthroat cast of characters, desperate for TV time, totally unprepared for their roles and their jobs and each week afraid of having their asses fired, and the other job I was the host of a smash television hit."

Several White House aides in the audience laughed in their tailcoats and ball gowns. But the joke, they knew, was on them.

------

Lemire reported from New York. Associated Press writers Jill Colvin, Catherine Lucey, and Ken Thomas contributed to this report.