President Trump speaks during a meeting with House and Senate legislators in the Roosevelt Room of the White House on Feb. 2, 2017. (Jabin Botsford/The Washington Post)

A month after announcing his candidacy, Donald Trump shocked the establishment by questioning the heroism of Sen. John McCain (R-Ariz.), a former prisoner of war. The near-unanimous verdict of the pundit class: Trump was doomed.

Eighteen months later, Trump is still insulting McCain — only now he’s doing so from the White House.

“He’s been losing so . . . long he doesn’t know how to win anymore,” Trump tweeted Thursday.

Despite all predictions — including his own — that the country would see a new, more “presidential” Trump once he took office, the commander in chief has barely changed from the impulsive candidate who blew up every political norm that stood between him and the White House.

He is still tweeting at odd hours, calling people names, promoting his family’s business interests, bragging about crowd sizes, complaining about media coverage and lashing out at anyone who challenges him, including members of his own party and a federal judge. His White House seems just as chaotic, tumultuous and discordant as his campaign was.

(Peter Stevenson/The Washington Post)

All of which is according to plan, his team insists.

“Part of the reason the president got elected is because he speaks his mind,” White House press secretary Sean Spicer said at Thursday’s news briefing. “He doesn’t hold it back, he’s authentic, and he’s not going to sit back.”

Washington, meanwhile, is beginning to figure out that it had better get used to it. Surreal is the new normal.

“Most people in Congress and elsewhere did harbor the fantasy that he would become a different person,” said Vin Weber, a former Republican congressman from Minnesota who is now a lobbyist. “I think they’re learning differently.”

Mark Salter, a confidant and former top aide to McCain, said he never expected Trump to change because that would have required “not just growing into the job, but growing up.”

Other Republicans were deluding themselves in predicting that another Trump would emerge once the enormous weight of the presidency was placed on his shoulders, Salter said. “They just couldn’t bring themselves to believe otherwise, because it would have been an indictment of them” for supporting Trump.

Lyndon B. Johnson once said: “The presidency has made every man who occupied it, no matter how small, bigger than he was, and no matter how big, not big enough for its demands.”

But in his first three weeks in office, Trump appears to be changing the presidency more than the reverse.

Rather than moderating his impulses, his top aides seem intent on amplifying them — pleasing their boss by attacking critics and the news media, defending his factually inaccurate assertions and adding to the growing pile of what counselor Kellyanne Conway called “alternative facts.”

Trump and those around him had long promised that he would tone down his style if elected. There was even talk that he might give up the Twitter account that functions as an expression of his id.

In an April rally in Pennsylvania, Trump promised: “At some point, I’m gonna be so presidential that you people will be so bored.”

Anthony Scaramucci, a prominent New York financier who now works at the White House, predicted the same during a Fox News interview in late December.

“I think that the gist of what happened during the election season is going to be slightly modified now,” Scaramucci said. “I think the candidate as president is going to be way more presidential and way more precise than people think. That’s my prediction.”

Reince Priebus, the former GOP chairman who is now Trump’s chief of staff, repeatedly used the word “pivot” to explain how the businessman was prepared to mature as he transitioned from the primaries to the general election and beyond.

“He has a lot of space to grow,” Priebus said in a July 17 interview with ABC News. “I think he’s much more precise in his rhetoric, in his tone, in his attack. I think he’s got a lot of room to grow. . . . He knows the pivot is important. He has been better, and I think he’s going to be great moving forward.”

Trump kept repeating the promise himself.

“When I’m president, I’m a different person,” Trump said at a rally in Pella, Iowa, last January. “I can do anything. I can be the most politically correct person that you’ve ever seen.”

Two weeks later, Trump told NBC News that he would be “much different, much different” as president.

“When you’re president, you act in a different way, there’s no question about that, and I would do that,” Trump said, after being questioned about why he called rival Sen. Ted Cruz (R-Tex.) a “p---y” at a rally in New Hampshire.

Yet there were other times when Trump made it clear he had no intention of undergoing an extreme makeover.

“I am who I am. It’s me. I don’t want to change,” Trump said in an interview in La Crosse, Wis., in August. “Everyone talks about, ‘Oh, well, you’ve got to pivot.’ . . . I don’t want to pivot. I mean, you have to be you. If you start pivoting, you’re not being honest with people.”

After he obliterated expectations and pulled out an electoral college win in November, Trump sent conflicting signals.

Days after the election, Lesley Stahl of “60 Minutes” asked him in an interview: “Are you going to sometimes have that same rhetoric that you had on the stump? Or are you going to rein it in?”

“Well, sometimes you need a certain rhetoric to get people motivated,” Trump responded. “I don’t want to be just a little nice monotone character and, in many cases, I will be.”

Stahl asked: “Can you be?”

“Sure I can,” Trump said. “I can be easily, that’s easier. Honestly, to do that, it’s easier.”

His Republican allies on Capitol Hill insist that Trump’s un­or­tho­dox style will not get in the way of their policy agenda.

Brendan Buck, chief communications adviser to House Speaker Paul D. Ryan (R-Wis.), said the speaker has a normal working relationship with the president and doesn’t get “distracted by whatever the statement out of the pool spray is or whatever the tweet is.”

“He’s got a unique way of doing things,” Buck said, “and we don’t ever expect that to change.”

Alice Crites contributed to this report.