As he embarked on a campaign swing across northern Ohio, President Obama announced new action against China in the World Trade Organization, challenging duties imposed last year on U.S. auto exports.

"Just this morning my administration took a new action to hold China accountable for unfair trade practices that harm American automakers," Obama said during a campaign stop in Maumee, Ohio. "We're going to make sure that competition is fair. That's what I believe. That's part of our vision for America."

The tough line toward China coincides with Obama's appeal to blue collar workers in Ohio, home to many U.S. auto manufacturers and suppliers. The bus tour - themed "Betting on America" - will promote the 2009 Obama-backed bailout of GM and Chrysler and portray the president as a champion of American manufacturing.

Despite the optics of an administration mix of politics with trade policy, White House spokesman Jay Carney disputed that the timing of the announcement was anything other than coincidence.

"This is an action that has been in development for quite a long time. USTR [the U.S. Trade Representative] studies these issues and prepares actions with great deliberation to ensure their success at WTO. This one has been under development for many, many months," Carney told reporters on Air Force One. "It can't suddenly be a political action because it happens during the campaign."

Carney noted that the new WTO complaint is the seventh the administration has filed against China and that the previous six have been "successful."

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Administration officials say the duties, which target Ohio-made cars like the Jeep Wrangler, affect $3.3 billion in exports, hampering prices and potentially imperiling jobs.

"The Chinese duties in question cover more than 80 percent of U.S. auto exports to China, including cars manufactured in Toledo and Marysville, Ohio, and Detroit and Lansing, Michigan," said Carney. "The duties disproportionately fall on General Motors and Chrysler products because of the actions that President Obama took, as you know, to support the auto industry during the financial crisis."

China cites Obama's 2009 taxpayer-funded bailout of U.S. automakers GM and Chrysler to claim that the companies received an unfair advantage in the global marketplace, akin to subsidies that are forbidden by WTO rules.