(CNN) -- President Barack Obama and Republican presidential nominee Mitt Romney went head-to-head on China, taxes, and jobs on Wednesday as the two campaigned throughout Ohio. Both sought to illustrate what the next four years would be like under their leadership as new polls indicated Obama exceeding 50% support among likely voters in Ohio, Florida and Pennsylvania. Those are all swing states that combined will account for nearly a quarter of the electoral votes needed to win the White House. Surveys suggest that Romney has lost his edge on the economy, the centerpiece of his campaign to highlight slow growth, trade tensions, and stubbornly high unemployment under Obama's leadership.
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NEW: Romney releases new campaign advertisement on the economy
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NEW: Obama and Romney challenge each other on China trade, key issue in Ohio
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Latest poll numbers show uphill battle in swing states for Romney
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Ohio has chosen the winning presidential candidate since 1964
Industry research shows that 800,000 jobs in @placeholder are tied to the auto industry, which also has railed against Chinese currency policies.