WASHINGTON - As US Republican presidential candidate Mitt Romney and President Barack Obama are stepping up attacks in their election campaigns against each other involving China, the topic of China is quickly becoming a political card in this year's presidential elections.

Experts say the reason is that it is relatively risk-free.

However, these attacks are worrying many, as they could lead to trade wars and further damaging the US economy if the candidates were forced to honor them next year when they were voted into office.

The first draw of this round of attacks was made by Romney. The former Massachusetts governor told supporters at a Virginia campaign event last week that it was China's "undervalued" currency - the Chinese yuan - that forced US manufacturers out of their jobs. His campaign, meanwhile, released an ad blaming Obama of being "soft" with China's "cheating," turning a blind eye to the fact that the Chinese currency has so far appreciated more than 30 percent against the US dollar since Beijing began to reform its exchange rate regime in 2005.

The Obama campaign responded this week by criticizing Romney of sending American jobs to China by investing in Chinese companies during his tenure at Bain Capital, a private equity firm Romney ran before entering politics.

The Obama administration also brought up a major trade case at the World Trade Organization (WTO) against China's subsidies to its automobile industry at the same day as Obama visited the industry-heavy swing-state of Ohio. The administration has brought up two major complaints at the WTO against China in the past two months, both during the same week as Obama visited the crucial state.

"These... subsidies," claimed Obama at a campaign rally Monday in Cincinnati, Ohio, "directly harm working men and women on the assembly lines in Ohio and Michigan and across the Midwest."

The president also used the event to accuse Romney, saying Romney's experience has been "owning companies that were called 'pioneers' in the business of outsourcing jobs to countries like China."

"There's no risk in slamming China in an American election," observed Peter Brown, assistant director of Quinnipiac University Polling Institute, at a Washington briefing Wednesday. "You're not going to lose a lot of votes that way, and you might gain them."

According to poll results released Tuesday by the Pew Research Center's Global Attitudes Project, although 65 percent of Americans view the relations between the United States and China as generally good, 59 percent of Americans say they are concerned about China's economic strength, and 45 percent say Obama is not tough enough against China.

This mentality, coupled with the fact that the US economic recovery is still sluggish, with no convincing path to growth from either side, is driving an increasing China-bashing in this election cycle.

Yet it is not totally risk-free, especially when one of the candidates is no longer a candidate next year, and has to honor his pledges to "get tough".

Newspapers such as Washington Post and The Wall Street Journal ran editorials in the past week, calling for a stop in China-bashing, while cautioning protectionism tendencies exhibited in both campaigns.

The business community also has reason to worry. Conservative policy group the Club for Growth, which champions pro-business, free-market views, issued a statement Monday, accusing both candidates of threatening to "enact anti-growth policies against China that will raise prices, incite a trade war, and do real damage to our country's economic recovery."