BEIJING - After a year of ups and downs in China-US relations, are the two giants heading for collision or cooperation in 2012, in the context of global economic woes and US presidential elections?

The answer is not clear, partly because of the contradicting messages from Washington in the past year. President Barack Obama said his country would conduct sound cooperation with China in the beginning but later met with the Dalai Lama, approved arms sales to Taiwan and interfered in the South China Sea issue.

Last year, China overtook Japan to become the world's second-largest economy after the United States, and the power shift has got on nerves of the world's sole superpower, which has long been plagued by economic woes and unemployment.

Undoubtedly, China-US relations are to undergo a new round of "stress test" in 2012 as this year will be politically sensitive due to the presidential elections in the United States and a number of other sensitive issues.

In election year, US presidential hopefuls would probably repeat a traditional China-bashing game to gain popularity. Take Republican front-runner Mitt Romney as an example, the former Massachusetts governor has been drumming up China threat in economic, military and cultural fields.

Trade is another hot issue as it is often attached to the exchange rate. Some US politicians assume that China artificially devalues its currency to gain advantage for its exports and that the exchange rate is the root cause of trade imbalances between the two countries.

But the old trick may not work every time as the two countries have seen their interests increasingly interwoven. Two-way trade increased 17 percent year-on-year to $363 billion in the first 10 months of 2011.

Cool-headed Americans definitely understand the significance of China-US trade. It is hoped that rhetoric on trade war would be restricted to electoral campaigns only.

Another issue that may add uncertainty to China-US relations in 2012 is America's high-profile return to Asia.

Recent US moves in the region have spawned suspicions that Washington's purpose is to counterbalance China's rising influence in Asia.

Facts in recent years have shown that the complicated ties between the two major countries are always mixed with consensus and disputes, competition and cooperation. The key is to maintain cooperation as the main stream in bilateral ties.

Thanks to the existing dialogue and communication mechanisms, the two sides have successfully avoided the situations where the two are at daggers drawn.

Leaders of the two countries have made frequent meetings that deepened political trust in the past year. The third round of Strategic and Economic Dialogue, which contained security officials for the first time, also promoted the two countries' mutual understanding in economic and military fields.

A stable and healthy China-US relationship will not only serve the two heavyweights' interests and benefit their peoples, but also help the world overcome the current economic woes.

Obama said his country welcomes a stronger, successful, prosperous and stable China, and China also hopes the United States can shake off its debt crisis as soon as possible, because that would provide huge economic opportunities for the two countries.

Despite the many differences and suspicions, many have reasons to believe that China and the United States would do their utmost in the new year to maintain a stable relationship and would carefully avoid conflicts that would cause real damage.