Joe Biden was sworn in as the 46th president of the United States on Wednesday, taking on the daunting task of trying to heal a nation that has been battered over the last year by a pandemic, economic malaise, political violence and incessant attacks on America’s democratic institutions by the man he is succeeding, Donald Trump.

In a 21-minute inaugural address that sought to unify a tense and divided America, President Biden called on the country to “lower the temperature” or else risk destroying itself.

“We have learned again that democracy is precious. Democracy is fragile,” Biden said in his speech, moments after he took his oath of office, standing on a platform that two weeks earlier had been overrun by a violent crowd of Trump loyalists trying to stop the certification of Biden’s victory. “And at this hour, my friends, democracy has prevailed.”

“We must end this uncivil war that pits red against blue, rural versus urban, conservative versus liberal,” he said.

“Here we stand, just days after a riotous mob thought they could use violence to silence the will of the people, to stop the work of our democracy, to drive us from this sacred ground,” he said.

“It did not happen. It will never happen.”

The day, more sombre than most inaugurations, mixed some pomp and pageantry – pop superstars Lady Gaga and Jennifer Lopez and country singer Garth Brooks all performed – with solemn rituals: after events at the Capitol, the new president led a wreath-laying ceremony at Arlington National Cemetery.

Biden and his new administration face several crises, the most urgent of which remains the coronavirus pandemic that has run rampant throughout the country over the last year. Biden took office a day after the pandemic’s death toll in the US reached 400,000.

Biden is counting on the Senate to confirm his cabinet nominees expeditiously and pass Covid-19 relief legislation, to respond to the pandemic’s economic fallout. But the chamber, which as of Wednesday is controlled by Biden’s Democratic Party, will also be consumed in the coming weeks with the trial of Trump, who was impeached by the House of Representatives just last week for inciting the insurrection against the US government.

Trump has still not admitted to his most zealous supporters, who believe him when he says the election was stolen, that he lost to Biden by 7 million votes in a fair contest. Trump was the first president since 1869 to skip his successor’s inauguration, flying earlier Wednesday morning to Florida and his Mar-a-Lago resort.

Before leaving Washington for the final time as commander in chief, Trump told a small crowd of supporters that the last four years had been “incredible”. He also wished luck to “the new administration” without saying Biden’s name.

Now the job belongs to Biden and his team, which includes his vice-president, Kamala Harris, who was also sworn in on Wednesday. Harris is the first US vice-president to be a woman, black or of South Asian descent.

In the hours after his swearing-in, Biden signed the first of a slew of executive orders expected in the coming days, which he can use to make a range of policy changes without congressional involvement. Among them, he signed a directive requiring people to wear masks on federal property to help stop the spread of Covid-19, and another reinserting the US in the 2015 Paris climate accord, which Trump had withdrawn from.

At her inaugural briefing later in the day, new White House press secretary Jen Psaki said that Biden’s priority was to rebuild alliances and regain “America’s seat at the global table”.

But some analysts say it will prove difficult if not impossible for the US to resume its role as the world’s leader, in no small part because of actions taken by Trump, while others said Biden’s speech showed how he might be able to unify the country once again.

“We have lost so much credibility and respect in the last several years that it will be impossible to return our image or influence to where we were in 2016 or 2000,” said Brett Bruen, a former US diplomat and now president of Global Situation Room, an international crisis management consultancy.

Corri Zoli, a professor at Syracuse University’s law school and Maxwell School of Citizenship and Public Affairs, said that Biden in his speech had “answered several concerns and criticisms well – he disarmed concerns that unity was a fantasy or dream”.

“He referenced the depth of his commitment to the nation (Constitution, etc,) by using Lincoln’s commitment ‘by his very soul’ to the Emancipation Proclamation – important for those who worry Biden is not up to the task,” she said by email.

Biden spent most of his speech focused on domestic issues but included a few words for an international community that is watching the US struggle to overcome multiple crises at once.

“Here’s my message to those beyond our borders,” Biden said. “America has been tested, and we’ve come out stronger for it.”

“We will repair our alliances and engage with the world once again, not to meet yesterday’s challenges, but today’s and tomorrow’s challenges,” he said.

Also featuring prominently in the day’s various addresses was a commitment to put facts and science at the heart of the new administration’s dealings with the public, particularly when it came to information around the coronavirus.

White House press conferences, sporadic under the Trump administration, would return to a daily schedule, said Psaki, who also forecasted more frequent briefings from health officials.

Speaking almost four years to the day since Trump’s then-press secretary, Sean Spicer, used his first briefing to peddle baseless claims about the size of Trump’s inauguration audience, Psaki said that Biden’s commitment was to “bring transparency and truth back to government, to share the truth even when it’s hard to hear. And that’s something I hope to deliver on in this role as well.”