Washington (AFP) - President Joe Biden urged unity and touted a blue-collar economic resurgence Tuesday in a rousing State of the Union speech before a raucous Congress that doubled as a bid to persuade voters he still has what it takes to seek reelection at the age of 80.

The Democrat, who has been written off even by some supporters as too old, gave as good as he got in an unusually boisterous event, with far-right Republicans heckling and mocking throughout.

At times smiling and joking, at times showing anger, Biden concluded his address, viewed on television by tens of millions of Americans, that "because the soul of this nation is strong..., the state of the union is strong."

And without mentioning the 2024 election, he said: "Let's finish the job."

The speech, clocking in at an hour and 12 minutes, was remarkable for the granular focus on kitchen table issues, rather than soaring rhetoric or foreign affairs.

The first mention of Ukraine, which Biden vowed would get US support against Russia for "as long as it takes," came just under an hour into the speech.

China -- which Biden warned would face a US response whenever it "threatens our sovereignty," as in last week's shooting down of an intruding high-tech Chinese balloon -- came even later.

Democracy 'bruised' but safe

Biden has yet to announce his run for a second term but is expected to declare soon. The State of the Union speech could serve as an opening audition.

He pitched a centrist, populist vision of a country healing after Covid and the turmoil of Donald Trump's one-term presidency. And Biden's patient, even humorous ripostes to Republican jeering backed up his claim to represent a calmer alternative to the still powerful Trump wing.

With the event sounding more like the British parliament's Question Time than the staid annual US tradition, Biden declared that US democracy was "bruised" but "unbowed and unbroken."

On a number of occasions, Speaker Kevin McCarthy, the Republican heading the party's narrow new majority in the House of Representatives, stood to applaud Biden -- and appeared to try to quiet his more radical party members in the chamber.

Populist economics

At the core of the speech was a full throated call for Made-in-America nationalism and populist policies to rebuild the US industrial heartland -- the kind of rhetoric that once helped Trump lead Republican gains in previously Democratic working class strongholds.

Biden touted unemployment figures, now at a half-century low, and the stabilizing of inflation, as he promised to fight for the "forgotten" people of the economy.

For decades, "manufacturing jobs moved overseas, factories closed down," Biden said.

"Jobs are coming back. Pride is coming back," he said. "This is my view of a blue-collar blueprint to rebuild America."

Among Biden's proposals in the speech was a new "billionaire tax" designed to "reward work, not just wealth."

And he hit out at big oil companies he accused of making "outrageous" profits.

"I ran for president to fundamentally change things to make sure our economy works for everyone, so we can all feel that pride," Biden said.

Taking economy 'hostage'

Biden warned Republicans in strong terms not to use their newfound power in the House to block the usually uncontroversial procedure extending the US debt limit -- something that could send the United States crashing into default on its national debt.

"Some of my Republican friends want to take the economy hostage," Biden said.

"Let's commit here tonight that the full faith and credit of the United States of America will never, ever be questioned."

Republicans say they want to see budget cuts to reduce the debt, but Biden went off script to pile pressure on plans floated by a minority in the opposition party to cut popular social security programs.

'We can't turn away'

The most emotional moment came when Biden called for reforms to policing and gun ownership laws. 

In the audience as First Lady Jill Biden's guests were Brandon Tsay, the 26-year-old man who disarmed the gunman in a January mass shooting in California, and also RowVaughn and Rodney Wells -- the parents of Tyre Nichols, a man whose death after a prolonged police beating in Memphis, Tennessee, shocked the nation.

"We can't turn away," Biden said, recalling the fear Black parents have of police when their children go outside.

"Do something," he said, prompting Nichols' parents to stand and applaud.

Delivering the Republican rebuttal to Biden, former Trump White House press secretary Sarah Huckabee Sanders lashed out at the "radical left" and what she said was an attack against the "freedom and peace" of patriotic Americans.

"It's crazy and it's wrong," said Sanders, who has been elected governor of Arkansas since leaving Trump's administration and is a rising star on the right.