President Barack Obama and Republican rival Mitt Romney have squared off on China and accused each other of backing policies that would move American jobs overseas as the US economy struggles to recover.
Both sides were competing for white working-class voters, with Mr Romney needing to win at least 60% of the white vote to offset Mr Obama's overwhelming edge with blacks and Hispanics.
Mr Obama's campaign is hoping to reduce Mr Romney's advantage among white working-class voters by portraying the Republican nominee as an out-of-touch multi-millionaire whose private equity firm downsized and outsourced jobs.
Mr Obama's team argued that Mr Romney had profited from and outsourced jobs to China. The President also rolled out a new 60-second, six million-dollar TV ad campaign in seven battleground states that casts Mr Romney as risky for the nation's recovery and features former president Bill Clinton saying: "They want to go back to the same old policies that got us in trouble in the first place."
Seven weeks before election day, both candidates took a rare break from campaigning even as they intensified their efforts on the economy, through the prism of China, with Mr Obama sensing an opportunity to undercut his Republican rival's strength and Mr Romney refusing to cede ground. The manoeuvring came as a new poll showed Mr Romney having lost his long-held advantage on the economy to the President even as the overall contest remains tight.
For Mr Romney, emphasising China was a way to refocus his campaign on the voters' number one issue and the central one of his campaign after a difficult week dominated by foreign policy, a weak spot for the Republican, in the wake of unrest at US embassies in the Middle East.
The shift to China also indicated Mr Romney's need to shore up support among the white working-class voters he needs to turn out for him in big numbers in November. "In 2008, candidate Obama promised to take China 'to the mat'," Mr Romney said in his weekly podcast. "But since then, he's let China run all over us."
Mr Obama's campaign said it welcomed the fight on China, an issue where it argues Mr Romney has numerous vulnerabilities. It released a new web video yesterday in which Obama deputy campaign manager Stephanie Cutter said Mr Romney holds investments in Chinese companies and outsourced jobs to China while running the private equity firm Bain Capital.
Mr Obama's quick counter underscored the importance of holding on to his recent gains in Ohio, a swing state with a large manufacturing base where many blame China for depressing the state's industries.
A new national survey by The New York Times and CBS News finds that Romney has lost his long-standing edge on the question of who voters view as most likely to restore the economy and create jobs. Despite that, the poll found the race narrowly divided.