WASHINGTON (AP) — Donald Trump enters the White House on Friday just as he entered the race for president: defiant, unfiltered, unbound by tradition and utterly confident in his chosen course.

In the 10 weeks since his surprise election as the nation's 45th president, Trump has violated decades of established diplomatic protocol, sent shockwaves through business boardrooms, tested long-standing ethics rules and continued his combative style of replying to any slight with a personal attack — on Twitter and in person.

Past presidents have described walking into the Oval Office for the first time as a humbling experience, one that in an instant makes clear the weight of their new role as caretaker of American democracy. Trump spent much of his transition making clear he sees things differently: Rather than change for the office, he argues, the office will change for him.

"They say it's not presidential to call up these massive leaders of business," Trump told a crowd in Indianapolis in December. That was after he negotiated a deal with an air conditioning company to keep jobs in the state, a move many economists derided as unworkable national economic policy.

"I think it's very presidential," he declared. "And if it's not presidential, that's OK. That's OK. Because I actually like doing it."

Even before he takes the oath of office, Trump has changed the very nature of presidency, breaking conventions and upending expectations for the leader of the free world.

Advisers who've spoken with Trump say the billionaire real estate mogul and reality TV star is aware of the historic nature of his new job. He's told friends that he's drawn to the ambition of Ronald Reagan, a Republican, and John F. Kennedy, a Democrat. He's thinking of spending his first night in the White House sleeping in the Lincoln Bedroom, according to some who dined with him recently in Florida.

But Trump also views himself as a kind of "sui generis" president, beholden to no one for his success and modeling himself after no leader who's come before. Trump has said he's read no biographies of former presidents. When asked to name his personal heroes in a recent interview, he mentioned his father before replying that he didn't "like the concept of heroes."

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"I don't think Trump has a great sense of the history of the White House. When you don't know your history, it's hard to fully respect the traditions," said historian Douglas Brinkley, who recently dined with Trump and other guests at his South Florida club. "This is not somebody who brags about how many history biographies he's read."

"He's somebody who brags about it as this is a big event and he's the maestro," he said.

That's a shift that thrills his supporters, who elected Trump to shake up what they see as an unresponsive and corrupt federal government in the "swamp" of Washington.

"I don't want him to change" said Iowa state Sen. Brad Zaun, one of Trump's earliest backers. "One of the reasons that I supported him is that he told it the way it was. He didn't beat around the bush. He didn't do the standard political talking points."

Trump won election with that approach, but he's yet to win over the country. His Electoral College victory was tempered by a loss in the popular vote to Democrat Hillary Clinton by nearly 3 million ballots. The protests planned for the day after his inauguration threaten to draw more people to the National Mall than his official events.

Polls over the past week show that Trump is poised to enter the White House as the least popular president in four decades. Democrats remain staunchly opposed to him, independents have not rallied behind him and even Republicans are less enthusiastic than might be expected, according to the surveys.

In his typical reaction to poll results he doesn't like, Trump dismissed them as "rigged" in a Tuesday tweet.

It's exactly that kind of tweet that worries governing experts, lawmakers and other critics, who argue that traditional practices of the presidency protect the health of the American democracy.

"With notable exceptions, we've had a political culture in which presidents largely respect a series of unwritten rules that help democracy and the rule of law flourish," said Brendan Nyhan, a professor of government at Dartmouth College. "What's striking about Trump is he flouts norms that have previously been respected by both parties on a daily basis. He calls things into question that have never been questioned before."

Since winning the election, Trump has attacked Hollywood celebrities, civil rights icons and political rivals alike. He's moved markets by going after some companies, while praising others.

He's questioned the legitimacy of American institutions — appearing to trust the word of Russian President Vladimir Putin over the intelligence agencies he'll soon oversee, engaging in personal fights with journalists as he assails the free press and questioning the results of the election, even though it put him in office.

And he's lambasted the leaders of longstanding allied nations as he questions the post-World War II international order that won the Cold War and maintained peace in Europe for generations.

For Trump supporters, that no-holds-barred style is the very reason he won their votes. But for others in the country, it's a type of leadership they've seen before and fear will spread.

They point to Maine, where a Trump-like governor has roiled the state's government with offensive statements, a combative style and little respect for the Legislature, as a warning of what the nation might expect during a Trump administration.

Gov. Paul LePage's confrontational brand of politics has made it harder to pass legislation, build political coalitions or even conduct the basic workings of state government, say legislators and political consultants in the traditionally centrist state. He's created rifts with would-be Republican allies, demonized the media and tightly controlled basic information. At times, he's banned the heads of state agencies from appearing before legislative committees, making state budgeting and oversight difficult.

"What I'm concerned about nationally is what we've seen up here — that the checks and balances we take for granted disappear," said Lance Dutson, a Republican political strategist who worked to get LePage elected before later speaking out against him. "There are things that are happening up here that I really thought just couldn't happen."

There are signs that Trump's actions are already changing the traditions of government in Washington, freeing lawmakers and other officials from long-respected practices of federal politics.

More than 50 House Democrats plan to boycott Trump's inauguration ceremony, an unprecedented break with the bipartisan tradition of celebrating the peaceful transfer of power. While many Democrats were furious with the outcome of the 2000 election in which Republican George W. Bush defeated Al Gore after recounts and a Supreme Court ruling, they generally attended Bush's inauguration ceremony.

"I will not celebrate a man who preaches a politics of division and hate," tweeted Keith Ellison, a Minnesota congressman who's bidding to head the Democratic National Committee.

Those who know Trump say the billionaire mogul delights in confounding establishment expectations, even as he craves approval from powerbrokers in New York and Washington.

"He was born with a chip on his shoulder, and he is very much the guy from Queens who looked across at Manhattan and envied but also to some degree hated the elites who occupied Manhattan," said Michael D'Antonio, author of "Never Enough," a Trump biography. "The way that he wants to disrupt institutions reflects this idea that the institutions haven't embraced him."

That's a style that may work better for a CEO of a family corporation — who has little oversight from corporate boards or shareholders — than a president constrained by a system of checks and balances. Former Cabinet officials say the layers of government bureaucracy, myriad regulations and intricacies of Congress will challenge Trump's style.

"A president doesn't have sweeping, universal authority. It is a very different operation than being a CEO who can fire people and hire people at will," said Kathleen Sebelius, a Democrat and former health and human services secretary. "He's never been part of any organization with a framework where institutional rules are in place."

President Barack Obama, who's offered Trump advice both publicly and privately, said he's urged the president-elect to hold onto some of the traditions of the office.

"The one thing I've said to him directly, and I would advise my Republican friends in Congress and supporters around the country, is just make sure that as we go forward certain norms, certain institutional traditions don't get eroded, because there's a reason they're in place," said Obama, in a recent interview with CBS' "60 Minutes."

But Trump's supporters say it's the institutions and Washington — and not the next president — that must change.

"Trump believes that he has a better understanding of how things work in the modern world than all of these so-called critics," said Newt Gingrich, a Trump adviser and former Republican House speaker, who has spoken with the president-elect about his presidency. "That's who he is.

"The rest of us are going to have to learn how to think through that."

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