The stage is now surrounded by tall fences and patrolled by extra police officers.

Two weeks ago, hundreds of people stormed up the steps of that stage behind where Joe Biden will be sworn in as the 46th president of the United States and broke into the Capitol.

When Biden takes the oath of office on Wednesday while three former presidents —  but not Biden's predecessor — sit nearby, he will face an increasingly polarized, pessimistic and pained nation, according to the latest national NBC News poll.

More than 7 in 10 voters believe the country is on the wrong track, another 7 in 10 think the next four years will remain politically divided, and a majority say they are mainly worried and pessimistic about the nation's future, the TV network reported on the eve of the inauguration.

Outgoing President Donald Trump, in a farewell speech Tuesday, touted his legacy, and wished luck to the next administration without mentioning Biden's name.

Biden flew into Washington on Tuesday afternoon after an emotional send-off in Delaware, where he told supporters, "there's always light" after the dark times.

His entrance to the capital and Trump's final full day as president coincided with the news that the number of deaths from COVID-19 in the US surged past 400,000, the worst public health crisis in decades.

Biden and Vice-President-elect Kamala Harris attended a ceremony at the Lincoln Memorial on Tuesday, grieving for the victims of the pandemic and vowing to begin to heal the country.

His biggest test after he is sworn in will be "continuing to be presidential — above the partisan bickering", according to William Banks, distinguished professor emeritus at the Syracuse University College of Law in New York.

Biden also will seek common ground to reach compromise on new policies to expedite his agenda in Congress on climate, energy, immigration and pandemic relief.

Banks said the unprecedented level of security in Washington is justified, because the risk of violence remains high.

The pandemic, coupled with the stepped-up security in Washington, unseen since the Sept 11, 2001, attacks, will reduce the traditionally joyous celebration witnessed by thousands of spectators to a gathering of a few.

Tens of thousands of armed National Guard troops and other law enforcement officers have turned the US capital into a fortress, where its iconic monuments are closed, along with the National Mall.

A window displayed on a bus stop near the State Department shows the photos of the Jan 6 protesters, seeking tips from the public to help identify those suspected of "assault on federal officers at the US Capitol".

Five people, including a police officer, died in the assault.

Cal Jillson, a political scientist and historian at Southern Methodist University in Dallas, also said Biden's inaugural address likely will focus on national unity, but he will also highlight the importance of more effectively addressing the coronavirus and speeding up the economic recovery.

The International Monetary Fund has predicted the US economy to contract by 4.3 percent in 2020.

The number of US workers applying for unemployment claims last week posted the biggest weekly gain since the pandemic hit last March, according to US Labor Department figures.

Jillson said most presidential inaugurations are national celebrations, even for many of those whose candidate didn't win the election.

"This inauguration takes place in a more divided nation. President Biden will have to lower the temperature of our national politics while slowly pulling the nation together," he told China Daily.

Biden wants Congress to act quickly on a massive stimulus package to revive the economy and has a target of seeing 100 million shots of coronavirus vaccine injected within his first 100 days in office.

However, Jillson noted that Biden's biggest challenge will be addressing the polarization in the public and the Congress.

"Simple competence in distributing and administering the coronavirus vaccine would go a long way toward meeting that challenge," he said.

Stanley Renshon, a political scientist at City University of New York, said he expected Biden to emphasize overcoming divisions, bringing Americans together and taking immediate steps to put the country on the right path.

"His biggest test will be governing a deeply divided county with a veneer of moderation while attempting to cloak a very liberal Democratic policy agenda that is being pushed decisively leftward. That is not a recipe for success," Renshon said.

Biden also should signal to the world that the US will recalibrate after four years of Trump, according to Edward Frantz, a presidential historian at the University of Indianapolis.

"How do you talk about returning to new normal while also not seeming arrogant about the United States' position in the world — especially after what's transpired over the last four years of the Trump administration and also with what foreign observers watched in horror as the riots transpired," Frantz was quoted by The Associated Press on Monday.

Francis Fukuyama, a famed political scientist, noted that where the US goes after Biden's inauguration is "anyone's guess". He said the major uncertainty is what will happen within the Republican Party.

More than half of voters say they believe there was no widespread voter fraud in the 2020 presidential election, but up to 73 percent Republicans say that they believe there was widespread voter fraud, according to a Quinnipiac University national poll released on Jan 11.

"Biden winning the White House with a bare Democratic majority in Congress won't be enough for the United States to recover its international standing: Trumpism must be repudiated and delegitimized root and branch, much as McCarthyism was in the 1950s," Fukuyama wrote for Foreign Affairs on Monday.

As to foreign policy, Biden's biggest test ultimately will be at home, according to the Bloomberg Editorial Board.

"The new president must persuade Americans of something many have forgotten — that engaging with the world will add to, not subtract from, their country's security and prosperity," it said in an op-ed article last week.