Despite the controversies that periodically flair up between China and Japan, both countries' willingness to shelve the long-standing dispute secured four decades of regional peace and stability, ever since the two countries normalized their relationship in 1972. However, by nationalizing the main islands in September 2012, Japan disturbed the status quo and forced China to respond. The US could have checked its ally's incautious and irresponsible behavior. Instead, it encouraged Tokyo: In April, US Defense Secretary Chuck Hagel said the Diaoyu Islands "fall under" the Japan-US Security Treaty, which requires the US to defend Japan.

In the South China Sea, if the US wished to act responsibly it would be building regional consensus based on international law. Ensuring that all Asian nations honor the UN Charter and the UN Convention on the Law of the Sea, which legislates maritime behavior, would be a good start.

But the US has not succeeded in convincing Asia-Pacific nations that these international laws are crucial to their foreign policy. Vietnam, the Philippines, and Malaysia have all tacitly or explicitly admitted Beijing's sovereignty over the islands and islets within the South China Sea's nine-dash line. However, these three countries have all seized some islands and islets on the Chinese side of the nine-dash line. The US has failed to fairly judge the disputes - in fact, once again, it encourages these nations to contest Chinese claims.

And even though the US has not ratified the UNCLOS, it has asked China to allow that convention to govern its maritime behavior. If the US were a responsible actor in the region, it would have ensured everyone plays by the same set of rules.

China is open to working with the Association of Southeast Asian Nations to draw up and implement regional rules. In mid-September, China discussed with ASEAN members a South China Sea Code of Conduct that would help reduce tensions and ensure responsible behavior. And in his keynote speech at the APEC summit, President Xi Jinping emphasized the importance of Asia-Pacific nations working together for their mutual benefit, and indicated a willingness to build regional consensus.

The US pivot to Asia is not unwelcome - but for it to be a responsible and sensible policy, it has to be a balanced one. Otherwise, US action will not only be counterproductive, but too costly for a nation currently mired in a budgetary quandary. No one wants the US to stay away from East Asia - but if it cannot manage the task, perhaps it should stay focused on the problems within its own borders.

The author is a columnist with China.org.cn. For more information please visit: http://www.jhzsvip.com/opinion/shendingli.htm

This article was first published at chinausfocus.com.