US Republican presidential hopeful Mitt Romney and President Barack Obama traded barbs on China, indicating that the topic might become a central piece of the 2012 campaign, Reuters reported. Romney, the current frontunner in the Republican presidential primary contest, said in a Wall Street Journal opinion piece that the Obama administration was “almost begging” Beijing to buy US debt, and called the current visit by Chinese Vice President Xi Jinping “empty pomp and ceremony.” Romney also accused the president of shying away from making human rights an issue in the Sino-American relationship. The Obama campaign responded by accusing Romney of flip-flopping, saying that the former governor had previously criticized the Obama administration’s enforcement of trade laws against China. The timing of the back-and-forth during Xi’s visit is unusual: “I just can’t recall there being such a targeted attack on a president’s China policy during a leader’s visit,” said Bonnie Glaser, a China expert at the Center for Strategic and International Studies.