WASHINGTON – John Kelly led tens of thousands of Marines in Iraq’s treacherous Anbar Province, was in charge of the entire U.S. military presence in Central and South America, yet now may have come across someone even he cannot manage:

The guy in the West Wing office a few steps away from his, the president of the United States.

Three weeks into the former Marine general’s tenure as White House chief of staff, Donald Trump had among his most disastrous spells yet since taking office in January, going off-script for a 15-minute, impromptu news conference in which he equated Nazis and KKK members with the protesters opposing them in Charlottesville, Virginia.

That followed a week in which Trump issued statements on Twitter that seemed to threaten a nuclear attack on North Korea, which followed a week in which he fabricated laudatory phone conversations with the president of Mexico and the leader of the Boy Scouts.

Kelly defenders say it is too soon to assess his effectiveness, and point to his success in ousting alt-right media executive Stephen Bannon from a top White House job – possibly enabling the Trump White House to end intra-party fights with Republicans in Congress and elsewhere.

“He was far too undisciplined, selfish and irresponsible to hold a senior post in the White House,” said Matt Mackowiak, a GOP consultant and chair of the Travis County Republican party in Austin, Texas. “This is a positive step but it doesn’t completely solve their problems.”

Others, including those who know Kelly from his 40-year military career, are skeptical. In his leadership roles in the Marines, Kelly had full authority to accomplish his missions. And while Kelly has been granted full authority over White House staff, that does not give him the ability to address the root cause of the administration’s dysfunction, critics said, which is Trump himself.

“He will be able to manage down and across the White House,” said one retired Army general who spoke on condition of anonymity to discuss the commander-in-chief. “But the challenge will be up.”

Kelly started his new job July 31, and immediately fired Anthony Scaramucci, a hedge fund manager whom Trump had hired as communications director just days earlier, over an obscenity filled interview he gave The New Yorker magazine. Scaramucci’s arrival had precipitated the departure of original chief of staff Reince Priebus and press secretary Sean Spicer, both of whom had advised Trump against the hire. Both Priebus and Spicer had been with the Republican National Committee and had played key roles in Trump’s campaign after he won the nomination.

The net effect is that three of Trump’s top advisers from his first six months have left the White House in a matter of weeks – effectively cutting his ties with the supporters who put him in the Oval Office.

“He is now untethered from the political structure that got him to the White House ― Reince was his tie to the establishment, Bannon to the base. He has neither,” said a top RNC member who spoke on condition of anonymity. “While I have never been a big fan of Bannon, this is going to hurt Trump and his presidency.”

Joshua Roberts / Reuters President Donald Trump shakes hands with John Kelly after he was sworn in as White House Chief of Staff in the Oval Office of the White House in Washington, U.S., July 31, 2017

The potential political consequences of these staff changes, though, are likely of minimal interest to Kelly. His military career was, of necessity, largely apolitical, although he did for a period serve as a congressional liaison.

Rather, his mission has been to make the White House function more normally, with more structure and an established process for interacting with Trump. To that end, he has inserted himself as the gatekeeper to the president’s schedule, both in person and via telephone.

Yet this process does not block Trump from reaching out on his own to whomever he wants for advice – and it clearly has not stopped him from issuing statements via Twitter, as he did Thursday , when he defended Confederate monuments using the same language white supremacist groups have used for decades, or Friday, when he attacked Republican senators whose votes he will need in coming legislation.

“There’s a limit to what Kelly can control,” Mackowiak said. “And within that universe, he’s done reasonably well so far.”

That Kelly is having trouble modifying Trump’s behavior should not have come as a surprise.

Having taken over a family business four decades ago worth $1 billion in today’s dollars, Trump has almost never in his adult life been forced to do something he didn’t want to do. The one exception was in the 1990s and 2000s, when the failure of his casinos put him on the brink of personal bankruptcy. His bankers forced him to unload his money-losing airline, his 282-foot motor yacht, his personal jetliner, and put him on a spending allowance.

From that point forward, including his primary and general election campaigns, Trump has largely done whatever he has wanted, even when the consequences have been damaging. Last October, for example, during a visit to Gettysburg, Pennsylvania, to lay out a concrete agenda for the first 100 days of his presidency, Trump opened the speech by promising to sue every woman who had come forward with allegations of sexual misconduct against him.

Mackowiak said Trump’s biggest problems are those he has generated himself. “It just doesn’t make any sense,” he said, adding that Kelly, to be successful, will need to persuade Trump of that. “The best-case scenario is that he’s shown that a different approach would be more successful.”