The most improbable of presidents, Donald Trump reshaped the office and shattered its centuries-old norms and traditions while dominating the national discourse like no one before.
Trump, governing by whim and tweet, deepened the nation's racial and cultural divides and undermined faith in its institutions. His legacy: a tumultuous four years that were marked by his impeachment, failures during the worst pandemic in a century and his refusal to accept defeat.
He smashed conceptions about how presidents behave and communicate, offering unvarnished thoughts and policy declarations alike, pulling back the curtain for the American people while enthralling supporters and unnerving foes — and sometimes allies — both at home and abroad.
While the nation would be hardpressed to elect another figure as disruptive as Trump, it remains to be seen how much of his imprint on the office itself, occupied by only 44 other men, will be indelible.
Already it shadows the work of his successor, President-elect Joe Biden, who framed his candidacy as a repudiation of Trump, offering himself as an antidote to the chaos and dissent of the past four years while vowing to restore dignity to the Oval Office.
“For all four years, this is someone who at every opportunity tried to stretch presidential power beyond the limits of the law,” said presidential historian Michael Beschloss.
“He altered the presidency in many ways, but many of them can be changed back almost overnight by a president who wants to make the point that there is a change.”
Trump's most enduring legacy may be his use of the trappings of the presidency to erode Americans' views of the institutions of their own government.
From his first moments in office, Trump waged an assault on the federal bureaucracy, casting a suspicious eye on career officials he deemed the “Deep State” and shaking Americans' confidence in civil servants and the levers of government.
Believing that the investigation into Russian election interference was a crusade to undermine him, Trump went after the intelligence agencies and Justice Department — calling out leaders by name — and later unleashed broadsides against the man running the probe, respected special counsel Robert Mueller.
His other targets were legion: the Supreme Court for insufficient loyalty; the post office for its handling of mail-in ballots; even the integrity of the vote itself with his baseless claims of election fraud.
“In the past, presidents who lost were always willing to turn the office over to the next person. They were willing to accept the vote of the American public,” said Richard Waterman, who studies the presidency at the University of Kentucky.
“What we're seeing right now is really an assault on the institutions of democracy.” Current polling suggests that many Americans, and a majority of Republicans, feel that Biden was illegitimately elected, damaging his credibility as he takes office during a crisis and also creating a template of deep suspicion for future elections.
“That's a cancer,” Waterman said.
“I don't know if the cancer can be removed from the presidency without doing damage to the office itself. I think he's done tremendous damage in the last several weeks.” Jeopardizing the peaceful transfer of power was hardly Trump's first assault on the traditions of the presidency.
He didn't release his tax returns or divest himself from his businesses.
He doled out government resources on a partisan basis and undermined his own scientists. He rage tweeted at members of his own party and used government property for political purposes, including the White House as the backdrop for his renomination acceptance speech.
Trump used National Guard troops to clear a largely peaceful protest across from the White House for a photo-op.
He named a secretary of defence, Jim Mattis, who needed a congressional waiver to serve because the retired general had not been out of uniform for the seven years required by law.
In that one example, Biden has followed Trump's lead, nominating for Pentagon chief retired Gen. Lloyd Austin, who also will need a waiver.
Trump's disruption extended to the global stage as well, where he cast doubt on once-inviolable alliances like NATO and bilateral partnerships with a host of allies.
His “America First” foreign policy emanated more from preconceived notions of past slights than current facts on the ground.
He unilaterally pulled troops from Afghanistan, Somalia, Iraq and Syria, each time drawing bipartisan fire for undermining the very purpose of the American deployment.
He pulled out of multinational environmental agreements, an action that scientists warn may have accelerated climate change.
He stepped away from accords that kept Iran's nuclear ambitions, if not its regional malevolence, in check.
And his presidency may be remembered for altering, perhaps permanently, the nature of the US-China relationship, dimming hopes for a peaceful emergence of China as a world power and laying the foundation for a new generation of economic and strategic rivalry.
While historians agree that Trump was a singular figure in the office, it will be decades before the consequences of his tenure are fully known. But some pieces of his legacy already are in place.