'Betting on America,' President Barack Obama hits the road on Thursday debuting the latest in a string of slogans adopted and then discarded as he seeks a cogent political meme as the economy drags.

He will strike his new theme on a two-day bus tour of rust belt swing states Ohio and Pennsylvania, where he will skewer rich Republican foe Mitt Romney, painted by his campaign brass as a tax-dodging outsourcer of American jobs.

The messy process of government and a stop-start-slow economy have robbed Obama of the clarity of the 'Hope and Change' slogan he ran on four years ago.

'Betting on America' gets its try out after Obama, who mastered the political moment in 2008, struggled to dominate the political dialogue while governing voters traumatized by years of economic anxiety.

When he touted investment in education and green energy, Obama sometimes appeared under the slogan 'Winning the Future' and urged Congress to act before banners reading 'We Can't Wait'.

Seeking traction for job-rich infrastructure projects, Obama's theme was 'An America Built to Last'.

In 2010, Obama launched a push to highlight stimulus spending under the moniker 'Recovery Summer' which was later mocked by Republicans as the economic rebound stumbled.

The 'Betting on America' bus tour is a new sign of Obama on offense, as he seeks to dismantle the central claim of Romney's candidacy -- that he is a job creating expert -- in two states crucial to November's election.

The Obama campaign said on Tuesday the president would use the two-day swing from Toledo, a long-time Ohio manufacturing hub, to the gritty city of Pittsburgh to lay out his blueprint for restoring middle class security.

"The president's vision stands in stark contrast to Mitt Romney, who believes in an economy built from the top down and supports the same policies that crashed our economy and devastated the middle class," a campaign statement said.

"As a corporate buyout specialist, he made massive profits by shuttering plants, firing workers and investing in companies that pioneered shipping of good American jobs overseas."

'The Betting on America' slogan strikes a patriotic tone for Obama, appropriately after the July 4 Independence Day holiday.

But it also positions him as a champion of the US worker, and raises the not so veiled hint from his team that Romney is doing the exact opposite.

As they argue Romney's former company Bain Capital helped firms active in the first wave of 'offshoring' US jobs overseas, Obama partisans got a new weapon Tuesday -- renewed focus on the multi-millionaire's complicated tax arrangements.

A report in Vanity Fair magazine suggested Romney exploited myriad loopholes and tax breaks, including offshore havens, to shield his vast wealth.

"Today we're learning more about Mitt Romney's bets against America," Obama campaign spokesman Ben LaBolt said.

"Was he avoiding paying his fair share of US taxes? Was he hedging against the dollar?''

"Until he releases his tax returns from that period, Americans will never know. This raises serious questions. If he has nothing to hide, why doesn't he just release his tax returns?"

The Romney camp accused Obama of trying to deflect attention from his own record.

"As job growth slows, manufacturing activity stalls, and our economy continues to sputter, President Obama knows he can't make a legitimate argument for another term in office," said Romney spokeswoman Andrea Saul.

"This is just the latest example of President Obama and his political machine saying or doing anything to distract from his abysmal record over the last four years."

Obama's two-pronged assault on Romney is designed in part to appeal to white, working class voters in industrial battlegrounds to whom Obama, America's first African American leader, has had difficulty courting.

But the carefully plotted narrative of the bus tour could be rudely interrupted on Friday, with the release of the latest Labor Department employment data.

A set of disappointing numbers similar to those recorded for May -- the economy only created a net 69,000 jobs and the unemployment rate ticked up to 8.2 per cent -- could undermine Obama's message and boost Romney.