WASHINGTON – What happens when a former Marine general used to structure and discipline is brought in to run the office of an unstructured and undisciplined chief executive?

The nation and the world are about to find out, with John Kelly spending his first day in the West Wing on Monday as President Donald Trump’s chief of staff.

“He will do a spectacular job, I have no doubt,” Trump said after an Oval Office swearing-in ceremony during the morning.

Kelly, who had been serving as Trump’s secretary of Homeland Security, responded: “I’ll try, sir.”

He appeared to make a statement about his seriousness on Day One, forcing communications director Anthony Scaramucci out of his job barely a week after Trump appointed him to it.

Scaramucci made waves last week in an obscenity-laced interview with The New Yorker, in which he boasted that he had direct access to Trump and could get everyone in the West Wing fired, if he wanted to.

White House press secretary Sarah Sanders said Monday that Trump thought his comments “were inappropriate for a person in that position.”

Scaramucci’s departure notwithstanding, whether Kelly’s promised “spectacular job” will include bringing order to a chaotic White House remains an open question.

Trump’s previous chief of staff, former Republican National Committee Chairman Reince Priebus, was never given the authority to manage Trump’s schedule or control who could visit him in the Oval Office ― traditional “gatekeeper” responsibilities that have allowed previous presidents to retain their focus on top priorities.

While Sanders said Kelly will have full authority and all staff will report to him, it remains to be seen how that stricture will be enforced, given Trump’s fondness for reaching out on his own to friends, family and former business associates for advice.

Perhaps more significant than the official organizational chart, though, is the personality of Kelly’s boss. The president frequently changes course on a variety of topics and generates controversy on a near-daily basis.

Just last week, for example, Trump delivered a highly political speech at a Boy Scouts gathering that forced the organization to apologize; encouraged police officers to physically hurt suspects they arrest; and delivered a series of insults to Republican senators for failing to pass a bill partially repealing the Affordable Care Act.

Over the weekend, Trump derided China for failing to rein in North Korea’s nuclear weapons program ― after earlier saying that a recent tutorial about the two countries from the Chinese president made him understand why such a task would be difficult.

“Trump only listens to Trump, and the culture of chaos at the White House starts at the top,” said Colin Kahl, who served as national security adviser to former Vice President Joe Biden. “Kelly may provide some discipline on the margins, but he won’t discipline the president.”

Trump defenders and the president himself argue that the “chaos” criticism is unfounded, and that he is delivering on his campaign promises.

“No WH chaos!” Trump wrote at the end of a tweet Monday morning summarizing what he believes are his accomplishments. “Highest Stock Market EVER, best economic numbers in years, unemployment lowest in 17 years, wages raising, border secure, S.C.” (The S.C. presumably refers to his successful nomination of Neal Gorsuch to the Supreme Court.)

Randy Evans, an RNC member from Atlanta, said the issue is not Trump’s personal style, arguing that November’s election decided that the former businessman’s approach was acceptable enough to make him president.

“What he needs is structure below him,” Evans said. “Anytime you go through a transition, it will be chaotic. The best you can do is move the chaos in a direction you want to go.”

Yet the idea that the chaos has been created by White House staff seems dubious. Every key member of that staff ― from the recently departed Priebus and ex-press secretary Sean Spicer to advisers Steve Bannon and Kellyanne Conway ― has spent years in structured work environments with measurable work outputs.

The glaring exception to that is Trump himself who, thanks to his father’s wealth, was able to run a family business with questionable results but zero accountability. Trump bankrupted his Atlantic City casinos and was losing big money on his airline. All were purchased on whims and against conventional business advice ― decisions that brought him to the brink of personal insolvency.

Indeed, the only people Trump has been forced to obey in his adult life appear to have been the bankers who restructured his loans and put him on a spending allowance in those years.

Kahl, Biden’s former national security adviser, said Trump’s lack of self-discipline will ultimately overcome anything his staff can do. “In the end, Kelly will likely have to choose between being co-opted and corrupted by Trump, or defending his honor and quitting. I wish him well, but his job is mission impossible,” Kahl said.

Former Trump campaign aide Michael Caputo, though, said Trump’s unpredictability is what he and his voters like about him, and that Kelly’s presence will make the president more effective. “I didn’t elect Donald Trump to be Ronald Reagan,” Caputo said. “I elected him to blow the place up.”