Donald Trump readies to be sworn in as 45th US president

Donald Trump is set to be sworn in as the 45th president of the United States today — winning vindication for his bare-knuckle White House bid and beginning a four-year term that promises to shake up Washington and the world.

"It all begins today! I will see you at 11am for the swearing-in. THE MOVEMENT CONTINUES - THE WORK BEGINS!" Trump tweeted from his overnight lodgings at Blair House, just steps from the White House.

An estimated 800,000 people will gather on the National Mall in the centre of the nation's capital to celebrate a man whose short 19-month political career has defied all predictions, and many norms.

In the cool Washington dawn, his most ardent supporters ignored forecasts of rain and began to make their way by metro, car and on foot to take part in history.

"I've been waiting for this for a long time," said Thomas Mendenhall, 68, a retired banker from Missouri. "We just want change."

LABELLED RACIST

When Trump descended the escalators of his glitzy New York tower in June 2015, his run for office and his supporters were dismissed and even mocked.

But shortly before midday Friday, Trump will place his hand on Abraham Lincoln's bible, recite the oath of office on the steps of the Capitol and become the most powerful man on earth.

His staff, many shunned by friends for supporting a man who has been labelled a racist and bigot by his critics, will become power players in the White House.

In the primaries, Trump dominated a crowded Republican presidential field with smash-mouth rhetoric and star power.

He rode that same wave of anti-elite sentiment to victory over Democrat Hillary Clinton in the November election.

At 70 years of age, he is the oldest man ever to begin work in the Oval Office.

POLITICAL GREENHORN

But the real estate mogul and one-time television reality star is also a political neophyte — he will be the first president never to have held elected office, served in the government or the armed forces.

For Trump's supporters, that is a central part of his appeal.

"He's somebody that's not a politician" said 59-year-old Sandra Jackson-Carter, a salon owner from Bakersville, California.

"He's going to unite the country and make America great again," she said. "This is history. There's nothing better." 

The change in Washington — in many ways a company town — was already palpable late Thursday when Trump bopped along to country music during a pre-inaugural concert at the foot of the Lincoln Memorial.

37PC RATING

The music popular in America's heartland had replaced the strains of Beyonce and Bruce Springsteen that marked Barack Obama's two terms at the White House.

For his critics, Trump's arrival in Washington on Thursday on-board an Air Force jet was more like a hostile takeover than a traditional changing of the guard.

Small demonstrations popped up across the city centre, with shouts of  "not my president." A much larger rally is planned for Saturday.

On Thursday evening, hundreds of protesters demonstrated outside a pro-Trump event, heckling and shouting at departing guests and lighting protest signs on fire before police used chemical spray on the crowd.

Trump enters office with a 37 percent approval rating, the lowest on record, according to a CBS News poll.

OBAMA STAFF

Most of Obama's White House staff have cleaned out their desks and the normally busy corridors of the West Wing were unusually quiet Friday. Staffers expressed relief at the prospect of rest, but foreboding about the road ahead.

That sentiment is echoed across many of the world's capitals. Trump has vowed to tear up Obama's policies and re-examine decades-old alliances with Europe and in Asia.

One of Obama's last acts in office was to speak to German Chancellor Angela Merkel, and declare trans-Atlantic ties vital for the world order — a statement that would have been a banal platitude before this rocky transition.

Still, Obama has one more part to play, hosting Trump and his wife Melania in the Blue Room of the White House for morning tea Friday.

OATH OF OFFICE

The two presidents and their families will then travel the 2.5 miles (four kilometres) down Pennsylvania Avenue to the swearing-in ceremony at the Capitol.

After promising to "faithfully execute the office of president of the United States" and "preserve, protect and defend the Constitution of the United States," Trump will deliver the most important speech of his life.

Inaugural addresses — from Lincoln to John F. Kennedy — echo across American history. Phrases like "malice towards none" and "ask not what your country can do for you" have been carved into the vernacular.

The most noted inaugural addresses had sought to lift Americans' gaze up from the rancour and troubles of the day toward the horizon and a better tomorrow.

SPEECH

Trump aides are promising an address that is at once short — at around 20 minutes — and philosophical.

"It's going to be a very personal and sincere statement about his vision for the country," said incoming White House press secretary Sean Spicer.

"He will discuss what it means to be an American, the challenges that we face, as members of the middle class, that they face," he said.

"I think it's going to be less of an agenda and more of a philosophical document, a vision of where he sees the country, the proper role of government, the role of citizens."

UNITY VOW

In brief remarks on the eve of becoming president, Trump vowed to bring unity, but there was also a rallying cry for his base.

"We're going to unify our country," he said, before telling supporters: "You're not forgotten anymore."

"We're going to get our jobs back. We're not going to let other countries take our jobs any longer. We're going to build up our great military."

After his speech, Trump will attend a luncheon inside the Capitol, before heading back to the White House to begin the business of governing.