President Trump speaks to business leaders during a Feb. 3 strategy and policy forum in the State Dining Room of the White House. (Jabin Botsford/The Washington Post)

Donald Trump, elected on a promise to bring an unabashedly autocratic leadership style to the presidency, is rapidly learning that even the most powerful job in the world has limits.

“I alone can fix it,” he declared in the most memorable line of his nomination acceptance speech at the Republican National Convention last summer.

But as he heads into his third full week in office, Trump has seen his controversial immigration order blocked by a federal judge. Republican allies in Congress are grumbling about not being consulted. Foreign leaders are refusing to buckle to his bluster. A rebellion is brewing within the emboldened federal bureaucracy.

Meanwhile, his own aides are bickering and providing the news media a steady stream of leaks about palace intrigue.

The establishment that he vowed to blow up is more potent in practice than it seemed when he was making it his political foil during an election season.

Vice President Mike Pence, shown here on Jan. 23. (Matt McClain/The Washington Post)

In fact, it was built to be that way. Trump’s difficulties come partly from the constraints faced by all presidents in a system in which there are three branches of government, each empowered to impose checks and balances on the others. That is a far different environment from Trump’s previous career running a family-owned real estate and branding empire.

Other Trump frustrations are the result of his unique circumstances and personal predilections.

He and the top echelon of his White House team have virtually no government experience and made dramatic moves before his Cabinet was in place to give him a sounding board and reinforcement. That helps explain Trump’s error — and subsequent reversal — of including an estimated half-million legal U.S. residents in his order that people born in seven Muslim-majority countries not be allowed to enter into the United States.

Not since his election-night victory speech has Trump sounded many persuasive or conciliatory notes toward the opposition or seemed to factor in the dead weight of his unpopularity with the majority of the electorate that voted against him. Instead, he has continued to tweet insults at critics and dissenters.

“Just cannot believe a judge would put our country in such peril,” Trump wrote on Twitter on Sunday, referring to U.S. District Judge James L. Robart, who suspended the immigration order. “If something happens blame him and court system. People pouring in. Bad!”

Asked Sunday on NBC’s “Meet the Press” whether Trump had done enough to heal the nation’s divisions, House Speaker Paul D. Ryan (R-Wis.) said: “I think he’s going to feel his way through this. And look, what I’m excited about is that he wants to hit the ground running and he’s very much a man of action.”

But to each action, there has been a reaction.

In Trump’s early conversations with foreign leaders, he has taken unyielding stances, even with friendly countries. For example, he demanded that Mexican leaders agree to pay for a border wall, and he initially appeared to balk at abiding by a deal with Australia negotiated by the Obama administration for the United States to resettle hundreds of refugees.

In both cases, his foreign counterparts refused to back down.

“President Trump puts a lot of emphasis on American sovereignty and putting America first,” said Tamara Cofman Wittes, a Middle East expert and former State Department official in the Obama administration. “That goes both ways. Every foreign leader is also a leader of a sovereign nation — many of them democratically elected, many of them elected by wider margins. They have their own base. The fact that he says he wants something does not necessarily move them along.”

Before Robart suspended it, Trump’s immigration order, which sought to ban refugees from Syria indefinitely and halt immigration from six other ­majority-Muslim countries temporarily, drew an official rebuke from hundreds of State Department employees, who used a “dissent channel” to register their views. That prompted White House press secretary Sean Spicer to assert that the career Foreign Service officers should “get with the program” or quit.

Still other officials are going outside channels to an unauthorized though effective way of airing their differences: leaking to the media. Draft versions of executive orders and transcripts of confidential conversations have made their way into the public domain.

The question now is whether Trump will adjust in the face of the institutional and political realities or maintain his imperious posture.

“If they keep up on this trajectory, we will have a full-blown ­constitutional crisis,” said Elaine ­Kamarck, director of the liberal-leaning Brookings Institution’s Center for Effective Public Management.

Publicly, the Trump White House has been unapologetic about its approach.

“We’re very confident the president is operating within his authority as president,” Vice President Pence said Sunday on “Meet the Press.” He added that the immigration order “was not done hastily,” while acknowledging that some lawmakers were not informed ahead of time “through the usual niceties in Washington.”

Pence suggested that the public supports Trump’s moves even if they have rankled the Washington establishment.

“The American people know the threats we face are real,” he said. “They elected Donald Trump for many reasons, but one is to rethink immigration policies to ensure that people who represent threats don’t come into this country.”

Of the rampant protests across the country in the fortnight since Trump’s inauguration, Pence said: “We respect the right of every American to be heard in protests and online. But I believe the majority of American people are grateful to have a president who takes decisive action.”

But what bothers even members of his own party is Trump’s tendency to personalize the inevitable constraints that any president must face. Trump ridiculed Robart as a “so-called judge” even though he is a Republican appointee whom the Senate voted 99 to 0 to confirm in 2004.

“I think it is best not to single out judges for criticism,” Senate Majority Leader Mitch McConnell (R-Ky.) said Sunday on CNN’s “State of the Union.” “We all get disappointed from time to time at the outcome in courts on things that we care about. But I think it is best to avoid criticizing judges individually.”

Pence countered that the president “has every right to criticize the other two branches of government. I think people find it very refreshing. Not only do they understand the president’s mind, but they understand how he feels about certain things. He expresses himself in a unique way.”

The vice president’s defense of Trump represents a sharp contrast to how Republican leaders treated President Barack Obama, who in his second term ramped up the use of executive actions, saying Congress was hopelessly gridlocked through partisan politics.

“This is a president that views his presidency more as a kingship than it does as bound by Article Two of the Constitution,” Reince Priebus, then the chairman of the Republican National Committee, said in July 2014. Priebus now serves as Trump’s White House chief of staff.

When Obama moved in November 2014 to unilaterally alter immigration policy by allowing millions of undocumented immigrants the right to apply for work permits, GOP leaders erupted in howls of protest, derisively referring to Obama as an “emperor” and an “imperial president” attempting to skirt the legislative branch.

“Their hypocrisy on this is unbelievable,” said Simon Rosenberg, founder of NDN, a liberal think tank in Washington. Obama, Rosenberg said, acted only after lengthy public debate and consultations with Congress and federal agencies affected by rule changes.

By contrast, Rosenberg said, Trump’s immigration order “was hastily thrown together. The leading law enforcement agent of the government said she did not think it was legal. It’s completely at odds with the way Obama’s executive order was managed.”

More generally, Rosenberg said: “I’m tired of the notion that we have to give him credit for keeping his promises and doing it quickly, when he’s doing it in a way that violates the law. He can do better and do it in a way that maintains a commitment to democratic norms.”

Correction: A photo caption earlier misattributed a quote to Mike Pence.