An optimistic Joe Biden will seek to lift an often unenthusiastic nation with a State of the Union address showcasing his efforts to rebuild the US economy - and setting the stage for the 80-year-old president's bid for re-election in 2024.

After two years of managing the exit from the Covid pandemic, an end to the 20-year Afghan war debacle, the Western response against Russia's Ukraine invasion, and extreme US political tension, Mr Biden feels he has much to celebrate.

"I want to talk to the American people and let them know the state of affairs - what's going on, what I'm looking forward to working on," Mr Biden said yesterday.

On Capitol Hill, he will address the full Congress, nearly every senior government member, and a vast television audience, buoyed by news that the economy is recovering strongly from the pandemic, with the lowest unemployment in 50 years.

U2 lead singer Bono will be among First lady Jill Biden's guests at the speech. The Dubliner has been invited for his work to fight HIV/AIDS and poverty.

"This is a president who is incredibly optimistic," White House Press Secretary Karine Jean-Pierre said.

But the dramatic downing on Saturday of a huge Chinese balloon by a US Air Force fighter leaves the unstable relationship with the communist superpower literally looming over the Biden administration.

There are troubles closer to home, with two new polls showing that well over half of voters do not want Mr Biden to seek a second term in 2024.

Mr Biden spent the weekend at the presidential retreat Camp David, huddled with top advisors and speech writers to finesse the speech.

They have been writing for weeks, Ms Jean-Pierre said, but tweaks are ongoing "until the last minute".

But there is some good news for the US President. Inflation, which just a few months ago seemed a near-existential threat to the Biden presidency, is steadily ticking downward.

Hundreds of billions of taxpayer dollars are starting to flow out into programmes passed under Mr Biden to spur high-tech manufacturing and repair infrastructure.

On Friday, new figures showed joblessness hitting that half-century low.

This inspired Mr Biden to boast: "I'm happy to report that the state of the union and the state of our economy is strong."

Joe Biden speaks to reporters at the White House on Friday

Even if Mr Biden has yet to formally announce his 2024 candidacy, the SOTU, followed by two very campaign-like trips tomorrow and Thursday to Wisconsin and Florida, is expected to give him a big push.

However, the Chinese balloon drama, which Beijing claims it was an errant weather research balloon but the US government says it was a high-tech espionage device, shows how narratives in Washington easily take dangerous new turns.

When Mr Biden speaks, half of the Congress members in the chamber, as well as Speaker Kevin McCarthy sitting directly behind him, will be Republicans vowing to use their new, narrow House of Representatives majority to block his policies.

Already, a major crisis is brewing over Republican refusal to extend the US debt limit, usually a rubber stamp procedure.

Mr Biden's government warns of financial calamity, with major international implications, if Republicans stick to their guns, potentially pushing the United States into default.

Those kinds of uncertainties, as well as doubts over Mr Biden's future as the oldest person ever in the presidency, may be partly to blame for pessimism in the polls.

An ABC News-Washington Post Poll found that 58% of Democrats and Democratic-leaning independents said the party should find someone else for 2024.

Pressed on the dissatisfaction, Ms Jean-Pierre acknowledged that many voters remain worried by economic insecurity.

"It's an incredibly complicated time," she said. The State of the Union will be an "important moment".