Little noticed has been the adoption of a new tone in Chinese policy in South China Sea disputes. Senior Communist Party officials and media have begun to emphasize cooperation while last year, China and the ten members of the Association of Southeast Asian Nations put out a declaration that called on all parties involved to “exercise self restraint in the conduct of activities that would complicate or escalate disputes.”

The agreement with ASEAN is a departure from traditional Chinese foreign policy which usually prefers to resolve disputes bilaterally. In negotiations with a single country, it can exert greater pressure. Beijing’s willingness to engage Southeast Asia as a bloc is a notable sign of goodwill.

The rhetoric was translated into action in October when China chose not to obstruct Exxon’s oil exploration activities in waters that are claimed by both China and Vietnam.

Why this sudden shift? M. Taylor Fravel, who is an associate professor of political science and member of the Security Studies Program at the Massachusetts Institute of Technology, writes in Foreign Affairs that the primary goals of the friendlier policy are “to restore China’s tarnished image in East Asia and to reduce the rationale for a more active American role there.”

China appears to realize that its combativeness, far from compelling neighbors to make concessions, created a shared interest among nations in Southeast Asia — “and an incentive for them to seek support from Washington.”

Economically, these countries, ranging from traditional American allies like Japan and the Philippines to emerging markets as Indonesia and Vietnam, are increasingly dependent on China but for security, they look to the United States for balance. President Barack Obama reassured them in November that, “The United States is a Pacific power and we are here to stay.”

His words echoed Secretary of State Hillary Clinton’s assertion in 2010 that stability in Southeast Asia is of “national interest” to the United States, a claim that bothered officials in Beijing where the Foreign Ministry almost immediately countered that, “China is a big country and other countries are small countries and that is just a fact.”

China’s revisionist border claims antagonized its neighbors and the United States alike which have both emphasized the importance of safeguarding free shipping though this strategically positioned body of water.

A study by the RAND Corporation, a public policy think tank, last year identified the South China Sea region as one of the hotspots where conflict between China and the United States could erupt.

Depending on the nature and severity of a conflict, American objectives could range from enforcing freedom of navigation against a Chinese effort to control maritime activities in the South China Sea, to helping the Philippines defend itself from an air and maritime attack, to supporting Vietnam and shielding Thailand — another treaty ally — in the event of a land war in Southeast Asia.

Indeed, the Chinese posturing in the South China Sea necessitated the American “pivot” to East Asia which forced the Chinese to rethink their policy. Fravel believes that “the new approach reflects a strategic logic” and therefore “might endure, signaling a more significant Chinese foreign policy shift.”