President Barack Obama's mission in Tuesday's State of the Union address is simple to state, yet tough to pull off.

He must begin to convince Americans that despite high unemployment, a slow economic recovery and a mood of prolonged national gloom spawned by the worst recession in decades, he deserves another four years in the White House.

Cheers and standing ovations by lawmakers will ring out aroundObama in the House of Representatives as he embarks on his annual showpiece speech at 9:00 pm (0100 GMT).

But the ritual theatrics will do little to disguise the toxicity of Washington politics, the clouds around his reelection bid or the agony of millions of American voters struggling to make ends meet or find a job.

State of the Union addresses, especially those early in administrations, are often laundry lists of policies and programs, many of which quickly expire.

This time, Obama's speech may be a little different, as the president sketches a blueprint for his reelection run and asks voters to choose between his economic vision and that of Republicans.

"We can go in two directions -- one is towards less opportunity and less fairness," Obama told supporters in a video preview on Saturday, hinting at a new attempt to hike taxes on the richest Americans.

"Or we can fight for where I think we need to go -- building an economy that works for everyone -- not just the wealthy few."

The White House promises new programs in the speech that could help alleviate economic pain right away and insists Obama still wants to pass bills despite devoting more time to November's election.

Aides acknowledge Obama will also look long-term, in what will be his best chance for months to leverage the symbolic power of the presidency for personal political gain.

"The direction and the vision that the president will describe... is not limited to the calendar year of 2012," spokesman Jay Carney said.

"The broader vision is about the direction he believes that we need to move this country and that's a project that last longer than a year. It's a project that he has been engaged in for three years and he hopes to be engaged in for another five."

Obama knows that he will have to overcome a somber public mood, and a perception that his three years in office so far have failed to turn around the economy.

Unemployment, though falling, is at 8.6 percent, the housing market is moribund and only 13 percent of Americans polled by Gallup in a new survey released Monday were satisfied with the US economy.

Those figures add up to a tough reelection race.

Though they hope the recovery will gather momentum, senior Obama aides know that economic factors beyond their control -- perhaps European debt contagion spilling across the Atlantic -- could further erode Obama's prospects.

So the president is conjuring up an alternative reality -- posing as a populist warrior for the middle class dedicated to a new economy where all Americans get a "fair shake."

This long-term vision, and Obama's speech on Tuesday, will be based on four pillars: plans to boost manufacturing, homegrown and alternative energy, a bid to provide workers with new skills and a drive to renew "American values."

The White House says the president has created 3.2 million private sector jobs in three years, staved off a second Great Depression, saved the US auto industry and passed health reform which halted abuses by insurance giants.

But Obama's foes plan a strong rebuttal: House Speaker John Boehner has already predicted the speech will be "pathetic."

Republicans will argue that Obama has hiked taxes, stifled job creating entrepreneurs with over regulation, piled up government debt and lost America's cherished AAA credit rating.

Republican presidential hopeful Newt Gingrich brands Obama as an extreme "radical" and his foe Mitt Romney claims Obama is out of the American mainstream and dreams of a European-style socialist state.

Obama will surely highlight a promise kept to withdraw all US troops from Iraq last year, the operation that killed Osama bin Laden and likely the deepening sanctions shackling Iran over its nuclear program.

The president, under pressure from Republicans over China's economic policies, which many observers see as anti-competitive and damaging to the US economy, may also signal a tougher election year posture towards Beijing.