In order to counterbalance China's influence in the region, Washington is bound to strengthen its political, economic and military ties with ASEAN member countries.

Further, from the perspective of US' global security strategy, Washington is increasingly considering China as a strategic adversary. By joining the EAS, the US wants to turn the regional cooperation mechanism into a platform for containing China by dint of its influence in the political and security realm.

In fact, the US has been using some of the regional mechanisms to contain China. For example, while attending the ASEAN Regional Forum, Hillary Clinton urged all the countries concerned to develop an international mechanism to resolve disputes over competing claims for territory in the South China Sea - a statement that evoked strong opposition from Beijing.

Russia has for long intended to be a part of the EAS and has participated in its meetings as an observer ever since the first summit. On December 12, 2005, the then Russian President Vladimir Putin attended the first EAS as a distinguished guest and expressed Moscow's wish to join the summit.

Russian analysts believe ASEAN is one of the core mechanisms to promote the country's integration into the Asia-Pacific region. Enhancing cooperation with countries in the Asia-Pacific region is helpful for the development of Russia's Siberian and the Far Eastern regions. Besides economic cooperation, Moscow also wants to resume and extend its influence in East Asia.

China's response to the move to invite the US and Russia as new EAS members has been quite thoughtful and calm. China has always advocated that cooperation among East Asian countries should be open and accommodating, and that the changing regional architecture must be used to promote peace, development, cooperation and prosperity in East Asia, in accordance with the region's diversity.

China has said that the ASEAN should play a dominant role in the changing process, Foreign Minister Yang Jiechi said in Hanoi on July 21. Foreign Ministry spokesman Qin Gang said recently that China attaches importance to and respects the consensus reached among the ASEAN members concerning the enlargement of the EAS and that China would maintain close contacts with related parties until a consensus is reached.

The news that Obama would attend next year's EAS in Indonesia indicates that this enlargement is a foregone conclusion. With both countries' inclusion, the geopolitical situation in East Asia will change accordingly, and all forces will certainly make strategic adjustments to deal with the impact brought about by the evolving situation.

ASEAN has stressed its central role in the regional architecture, and has said that its core status in any newly formed regional cooperation mechanism must be respected. But, with the inclusion of a number of powers, with its attendant competing interests and conflicts, some ASEAN member countries also fear that their lead roles in the grouping would be eroded.

In addition, some analysts think that since China and Russia cooperate closely on some international issues, the potential for China-Russia coordination at the EAS might balance out the US. But in fact, the US-Russia relationship has been thawing recently.

The author is deputy director of the Center for Asia-Pacific Studies, Peking University.