Those who love and fear President-elect Donald Trump agree on one thing: He is bent on upending nearly every aspect of the presidency.
But now that he has taken the oath of office and enters the White House on Friday, Trump's mythology will begin to meet reality. And the debate has already begun over which elements of Trumpism will be truly revolutionary and which will simply represent a break from his party or a hard turn from President Obama.
Those questions will be central to Trump's administration, as factions within his close circle and Republican leaders in Congress vie for influence while Trump himself confronts Washington traditions that have evolved to withstand dramatic change.
The most radical aspect of Trump's presidency is likely to be the man occupying it. He has flouted ethics standards, refused to release tax returns, bashed the intelligence community, maligned the press, challenged facts and communicated unlike anyone who has held the office.
Trump's promises to end trade deals and negotiate lower drug prices fall into another category, in that they contradict decades of Republican economics. Yet neither idea falls outside the typical boundaries of policy debate.
But if Trump chooses to ban Muslims from entering the country, or creates a religious-based registry, that would certainly qualify as radical. And Trump's suggestion during the campaign that more allied countries might want to build nuclear weapons to defend themselves could also put him in uncharted territory.
Other possibilities raised during his campaign and transition, such as dropping the ban on waterboarding and reconfiguring post-World War II alliances in Europe, may also qualify as tectonic shifts in the world order, but are nonetheless resonant of an earlier era. Though Trump would face strong resistance from the intelligence, foreign policy and military establishments by taking either of those actions, nations do shift alliances, and waterboarding, while condemned by human rights groups and formally outlawed in 2015, was used covertly on captives during the Bush administration.
Trump's impact on policy will take time to discern. Congressional leaders have already begun asserting their own priorities, which could slow the pace of legislation on Capitol Hill and may alter Trump's course. Past presidents have learned it is not easy to accomplish big change that falls within the normal political boundaries, much less redefine those boundaries as Trump has vowed.
"Whatever a president says and however he says it, it's going to have some impact," said Leon E. Panetta, who served in Congress and in key Cabinet roles for Presidents Clinton and Obama. "In order to really create change, I think the president is in for a real big frustration when he finds out that to really get things done that he wants to get done for the country that he's going to have to work through the process."
Trump and his allies have been inconsistent on which ideas he would pursue. But they have stood by the notion that Trump will not be bound by traditional rules. Former House Speaker Newt Gingrich, a close advisor during the campaign, said the establishment should not assume that Trump and his team will be cowed by their move to the Oval Office.
"The city keeps hoping that they won't be the guys who won the election," said Gingrich. "And I think the city's going to be disappointed."
More certain is Trump's personal impact on the office of the presidency.
Historians are hard-pressed to find anyone who has come into office quite like Trump, a true outsider who is filling his Cabinet with others who also lack government experience. Some Cabinet picks have shown disdain or outright hostility for the agencies they will run.
Some have compared Trump's outsized personality to that of Theodore Roosevelt or Andrew Jackson and his ability to tap grievance to Richard Nixon's. But Nixon's wars with the press were more visceral and his grievances with elites a more deeply felt result of his relatively poor childhood, according to John Aloysius Farrell, author of "Richard Nixon: The Life," a new biography.
Trump has forgone the usual attempts to reach out to opponents, instead using Twitter to lash out at enemies both large and small, inflame racial tensions and weigh in casually on risky topics such as nuclear weapons. It has prompted concern from global allies and record-low approval ratings for an incoming president that could affect his ability to rally the public.
"He's like the mountain goat who jumps from peak to peak in areas where the president has no responsibility, such as the Golden Globe Awards," said Stephen Hess, who served on the White House staffs of Presidents Eisenhower and Nixon and as an advisor to Presidents Ford and Carter. "We're testing America's traditional notion of presidents or how presidents act."
Other presidents have orchestrated dramatic shifts in foreign policy. Yet they have rarely attempted to do so before taking office, and never through a combination of phone calls and written messages delivered without consulting experts at the State Department.
Trump's former campaign manager, Corey Lewandowski, pointed approvingly to two forms of Trump outreach that have rattled norms. One was his phone call with Taiwanese President Tsai Ing-wen, which provoked authorities in China and alarmed foreign policy experts.
The other is his use of Twitter, phone calls and personal meetings to pressure individual companies over their foreign hiring practices or government contracts.
Trump used the interactions to sell his message, but drew criticism from economists who say a president does not have time to make significant change one business at a time, as mayors and governors often do to drum up publicity, nor will such moves have a significant effect on the national economy.
Trump won wider praise when he used Twitter to lobby fellow Republicans in Congress to keep a House ethics office that some were eager to gut.
Gingrich said Trump will deal with government the way Elon Musk, who created a privately financed space program, challenged the NASA bureaucracy. Americans elected Trump because the system is "decaying dramatically," Gingrich said.
"It's way too bureaucratic. It's way too dishonest. It's way too politically correct," he said. "It needs somebody like this to reset the game."
Yet many who have worked and studied government warn that Trump's lack of experienced hands around him will hamper his ability to reset the system, given its complexity.
Changing the rules all at once, as Trump is trying to do, creates more shock than government can absorb, said John Hudak, deputy director of the Center for Effective Public Management at the Brookings Institution. He compared it to his showing up at Trump Tower with no real estate experience and declaring to the president-elect that he planned to overhaul the rules of the industry in one swoop.
"He's going to laugh me right out the door," Hudak said.
Farrell sees the breakdown of decorum between Trump and his adversaries as a new mark within a trend that began after the Cold War ended, when normal cooperation between political opponents gave way to all-out partisan enmity. He pointed to Trump's news conference last week, which featured the type of unruly argument with a reporter that is typical of a New York media scrum, but unprecedented for a modern president-elect.
"Who knows who could come next? So it's hard to say this is truly going to set an Earth-shattering mark," Farrell said. "But it certainly seems to be far different."
11:20 a.m.: This article was updated to reflect that President Trump has taken the oath of office.