After the Republican and Democratic national conventions, Americans prepare to choose their next president on the basis of domestic economic issues. But China does matter, indirectly.

When US President Barack Obama assumed office, nine out of 10 Americans disapproved of the direction the country had taken during his predecessor George W. Bush's two terms. Even today, about 75 percent Americans disapprove the direction of the country.

Americans have been split by Obama's policies since the summer of 2008, despite high initial hopes. According to daily tracking polls, most Americans would have voted for Obama until the summer of 2012. If the presidential election were held today, the race would be almost even.