As China's power becomes ever more obvious, especially to neighbors in Asia, Chinese leaders are finding it increasingly difficult to reconcile soothing words with assertive actions.

The recent attempt by China's defense minister to assure Southeast Asian countries and other nations that see the South China Sea as a security and economic lifeline shows how Beijing's credibility is on the line.

At the Shangri-La Dialogue in Singapore, General Liang Guanglie recited the mantra intoned by top Chinese officials from President Hu Jintao down: that China's security policy is "purely defensive in nature"; that Beijing will "never seek hegemony or military expansion"; and that China was "committed to maintaining peace and stability in the South China Sea."