The ceremony will take place at noon (1700 GMT) inside the Rotunda of the U.S. Capitol, four years after a mob of Trump supporters breached the symbol of American democracy in an unsuccessful effort to forestall the Republican Trump's 2020 defeat to Democrat Joe Biden. The swearing-in was moved indoors for the first time in 40 years due to the extreme cold.
Trump, the first U.S. president since the 19th century to win a second term after losing the White House, has said he will pardon "on Day One" many of the more than 1,500 people charged in connection with the Jan. 6, 2021, attack.
That promise is among a flurry of executive actions concerning immigration, energy and tariffs that Trump intends to sign as soon as Monday after taking the oath of office. At a campaign-style rally on Sunday in Washington, Trump vowed to impose harsh immigration restrictions on his first day.
As he did in 2017, Trump enters office as a chaotic and disruptive force, vowing to remake the federal government and expressing deep skepticism about the U.S.-led alliances that have shaped post-World War Two global politics.
The former president returns to Washington emboldened after winning the national popular vote over Vice President Kamala Harris by more than 2 million votes thanks to a groundswell of voter frustration over persistent inflation, though he still fell just short of a 50% majority. In 2016, Trump won the Electoral College - and the presidency - despite receiving nearly 3 million fewer votes than Hillary Clinton.
Jeremi Suri, a presidential historian at the University of Texas at Austin, compared the present era to the late 19th century, when Grover Cleveland became the only other president to win non-consecutive terms. Like now, he said, that was a time of upheaval, as industrial advances transformed the economy, wealth inequality exploded and the proportion of immigrant Americans reached a historical peak.
"What we're really talking about is a fundamentally different economy, a fundamentally different country in terms of its racial and gender and social makeup, and we are as a country struggling to figure out what that means," he said. "It's an existential moment."
Trump will enjoy Republican majorities in both chambers of Congress that have been almost entirely purged of any intra-party dissenters. His advisers have outlined plans to replace nonpartisan bureaucrats with hand-picked loyalists.
Even before taking office, Trump established a rival power center in the weeks after his election victory, meeting world leaders and causing consternation by musing aloud about seizing the Panama Canal, taking control of NATO ally Denmark's territory of Greenland and imposing tariffs on the biggest U.S. trading partners.
His influence has already been felt in the Israel-Hamas announcement last week of a ceasefire deal. Trump, whose envoy joined the negotiations in Qatar, had warned of "hell to pay" if Hamas did not release its hostages before the inauguration.
Trump claimed during the campaign he would end the Russia-Ukraine war on his first day, but his advisers have acknowledged any peace deal will take months.
Unlike in 2017, when he filled many top jobs with institutionalists, Trump has prioritized fealty over experience in nominating a bevy of controversial cabinet picks, some of whom are outspoken critics of the agencies they have been tapped to lead.
He also has the backing of the world's richest man, Elon Musk, who spent more than $250 million to help get Trump elected. Other billionaire tech leaders who have sought to curry favor with the incoming administration, such as Amazon's Jeff Bezos, Meta's Mark Zuckerberg, Alphabet's Sundar Pichai and Apple's Tim Cook, will join Musk in attending Monday's ceremony, according to Reuters and other media.
Trump said on Sunday he will travel to California on Friday to visit fire-ravaged Los Angeles County.
'AMERICAN CARNAGE'
The inauguration will proceed amid heavy security after a campaign highlighted by an increase in political violence that included two assassination attempts against Trump, including one in which a bullet grazed his ear.
Federal authorities are also on alert after the New Year's Day attack in New Orleans, when investigators say a U.S. Army veteran inspired by the Islamic State drove a pickup truck into a crowd of revelers, killing 14. Last week, the FBI warned of potential copycat attacks.
Eight years ago, Trump delivered a bleak inaugural address vowing to end the "American carnage" of what he said were crime-ridden cities and soft borders, a departure from the tone of optimism most newly elected presidents have adopted.
Foreign governments will be scrutinizing the tenor of Trump's speech on Monday after he waged a campaign laced with inflammatory rhetoric.
The traditional parade down Pennsylvania Avenue past the White House will now take place indoors at the Capital One Arena, where Trump held his victory rally on Sunday. Trump will also attend three inaugural balls in the evening.
Amid the pageantry of the day, Trump will begin signing the first of what could be dozens of executive orders.
Some actions will begin tightening immigration rules by seeking to classify drug cartels as "foreign terrorist organizations" and declare an emergency at the U.S.-Mexico border, among other moves, a source familiar with the planning said. Other orders may aim to scrap Biden's environmental regulations and withdraw the U.S. from the Paris climate agreement, sources have said.
Many of the executive orders are likely to face legal challenges.
Winning the election also rid Trump of two federal indictments - for plotting to overturn the 2020 election and for retaining classified documents - thanks to a Justice Department policy that presidents cannot be prosecuted while in office.
In a report released last week, Special Counsel Jack Smith said he had gathered enough evidence to convict Trump in the election case if Trump had reached trial.
