WASHINGTON — Covid and a traumatic presidential election left the US reeling in 2020, but even with Donald Trump gone and Joe Biden promising to heal the nation there’ll be no quick return to normal in 2021.

For many in the world’s richest country, 2020 was the year that seemed never-ending — an infinite series of horror movie sequels shaking the economy, politics and society itself.

Biden, an old-school Washington politician who believes in traditional US diplomacy and what he refers to as “decency,” got elected on a promise to stop the chaos.

“It is time to turn the page,” he said this week.

The shift in mood at the White House after Inauguration Day on January 20 will be remarkable.

Out goes the most attention seeking president imaginable, and in comes a mild-mannered leader who says he seeks “to lower the temperature.”

But Trump clearly has no intention of giving up the limelight — or allowing the United States to forget the nationalist and populist passions that his administration worked so hard to stoke.

His extraordinary decision to deny that he lost the election, more than a month after it happened, is just part one in what he hopes will be yet another Trump-centered drama, possibly culminating with a new presidential run in 2024.

And Biden will have another, tougher foe breathing down his neck: Covid-19.

Even though vaccines are now coming online, the virus is at its most deadly, killing thousands of Americans a day. It’s forecast to get even worse before winter is over.

Trump has tried to take credit for the ultra-fast development of the vaccines — one of the few good news stories of 2020.

But it will largely fall to Biden next year to oversee the unprecedented logistical task of getting doses administered across 50 states.

And while Trump can blame the catastrophic disruption to the economy on the coronavirus, it will be Biden who finds himself being remembered for what happens during the hoped-for recovery in 2021.

‘Death Star’ 

With Trump running for a second term, perhaps it was always inevitable that 2020 was going to be a wild year.

The rules-breaking Republican began his year with acquittal along party lines in a Senate impeachment trial.

Emboldened, he then stormed out onto the reelection trail, holding rally after rally in front of large crowds.

The Trump campaign machine was so well-funded and so single-minded that its then manager, Brad Parscale, likened it to the Death Star in “Star Wars,” a weapon ready to annihilate everything in its path.

The Democrats, meanwhile, began the year eyeing a long, perilous primary season featuring a staggering two dozen candidates.

Clearly, Trump fancied his chances.

Unemployment was at rock bottom, the stock market at historic highs and in January Trump reached a truce — which he spun as a huge win — in his trade war with China.

Yes, he was historically unpopular, but what made him reviled by the left, like his anti-immigrant rhetoric, won adoration on the right.

He even joked to his crowds that he’d not only win four more years but an unconstitutional extra eight, 12 or more.

Invisible enemy 

What no one knew in the first days of the year was that the Covid-19 virus, at first an unknown disease in faraway China, was about to upend the landscape.

By the end of January, the Chinese city of Wuhan was under severe lockdown and Trump had stopped travel from China. Yet for months he and many others in the United States did not appear to understand or at least accept what was happening.

Trump called Covid the “invisible enemy.”

It was an unseen force which would kill more than 300,000 Americans by mid-December and wreck Trump’s entire reelection message of success and strength.

Biden, whose campaign rested heavily on his claim to be the safe pair of hands for a crisis-ridden America, will now face the monumental task of steering the country to recovery.

He’ll do this with Trump sniping from the sidelines and an opposition Republican party which has moved far to the right over the last four years, embracing Trump’s scorched earth brand.

Biden’s own party may also not prove an easy partner, with the Democrats’ left wing in no mood to toe the line.

Two runoff races in Georgia for the Senate on January 5 will decide who controls the upper house — and to a large extent how much room Biden will have to maneuver.

Yet Biden, 78, has insisted he goes into this new era hopeful.

As he said in August, accepting the Democratic nomination: “History will be able to say that the end of this chapter of American darkness began here tonight.”