In 2010 regional security in Southeast Asia was affected by three major developments: increased tensions in Sino-American relations, U.S. re-engagement with the region, and Chinese assertiveness in the South China Sea. Each of these developments when taken in combination posed a challenge to the Association of Southeast Asian Nations’ (ASEAN) self-proclaimed role as the “primary driving force” in regional affairs. ASEAN weathered these challenges and by year's end demonstrated that ASEAN continued to remain central to the region's security architecture.

Tensions in Sino-American Relations

In November 2009, China and the United States issued a joint statement at the conclusion of President Obama's visit to Beijing. Both leaders “agreed that respecting each other's core interests is extremely important to ensure steady progress in U.S.-China relations”. Early the following year, when the United States announced arms sales to Taiwan and President Obama received the Dalai Lama, Tibet's spiritual leader, in The White House, China reacted angrily to what it perceived as an infringement of its core interests. Beijing immediately suspended all military-to-military exchanges.

In early March the Obama administration dispatched two senior officials to Beijing where they were received by State Councilor Dai Bingguo. The visitors had hoped to focus discussions on the nuclear programmes under way in Iran and North Korea, trade and market access, and climate change and to elicit Chinese cooperation on these issues. But Councilor Dai demanded that the United States genuinely respect China's core interests by halting all future meetings with the Dalai Lama and arms sales to Taiwan.

The American officials were told by their counterparts that “China would not tolerate any interference in the South China Sea, now part of China's ‘core interest’ of sovereignty”. U.S. analysts quickly noted that this was the first time China had identified the South China Sea as a core interest, along with Tibet, Taiwan, and Xinjiang.

Whether or not China had elevated the South China Sea to a core interest in official national policy has become a point of controversy. However, according to Secretary of State Hillary Clinton, Dai Bingguo reasserted this claim at the 2nd U.S.-China Strategic and Economic Dialogue (S&ED), held in Beijing in May.