And then there were 18. The East Asian Summit (EAS) is an annual forum launched in 2005 at the initiative of the Association of Southeast Asian Nations (ASEAN). It initially included ASEAN's 10 member states plus three dialogue partners, China, Japan and South Korea, and also Australia, India and New Zealand.

This year, Russia and the United States will join the sixth summit that is normally held following the autumn annual ASEAN leaders' meetings. The EAS has focused on economic issues including the non-binding Cebu Declaration on East Asian Energy Security; a proposal for a Comprehensive Economic Partnership in East Asia (CEPEA); and an East Asia Free Trade Area, while more concretely establishing an Economic Research Institute for ASEAN and East Asia.

Economic integration, however, remains a distant goal as reflected in declarations about "redoubling" efforts and further studies.

Given the alphabet soup of regional organisations vying for space on member leaders' calendars and the consequent risk of summit fatigue, why the EAS? It is seen as a step towards an East Asian Community that draws on the core institutional history and the strengths of ASEAN and which also includes the largest and most dynamic global economies.

The overlapping Asia Pacific Economic Cooperation (APEC) has become an unwieldy body of 21 members, and despite being established in 1989 with limited expectations, it has managed to underwhelm. In charitable moments, it is referred to as four nouns in search of a verb, and is best known for the silly practice of leaders donning the national costumes of the host nation. Its geographically diverse membership (excluding India) is a significant drawback, while the EAS has greater coherence as a regional forum. Along with India, China and Japan see more potential in the EAS.

The EAS hopes to avoid APEC's fate of functional irrelevance. While the EAS draws on the existing institutions, networks, processes and mechanisms that have accompanied ASEAN's gradual expansion, APEC operates in a vacuum. Some have described EAS as a nascent Organisation of Economic Co-operation and Development for Asia, but there is a lot of work to be done before it can assume that role. The good news is that lots of pieces of the institutional puzzle are in place and operating.

The EAS is a natural progression from the ASEAN Plus Three (China, Japan and South Korea) process, an organic and incremental expansion that brings together the key regional players. The EAS is influenced by the "ASEAN way" with emphasis on sustaining a long-term vision through consensus, refraining from intervention in domestic affairs, while focusing on areas of common interest that facilitate common perceptions and collective action. The emphasis on consensus and harmony nurtures fraternity, but also carries the risk of rendering the EAS irrelevant.

The US is joining the EAS because it wants to play a role in strengthening and shaping the emerging regional architecture. The EAS is consistent with the multilateral inclinations of the Obama Administration and its desire to participate in a meaningful way in dealing with regional problems and charting the future. Russia's participation signals its growing interest in its Far East and its desire to tap into the dynamic potential of the region.

Last year at the Hanoi EAS, the US started shaking up the summit even before it joined when Secretary of State Hillary Clinton called on the forum to embrace an active agenda, citing maritime disputes between China and other members in the South China Sea. She signaled US expectations that the EAS deal with consequential issues such as these maritime disputes, but also climate change, nuclear proliferation, a conventional arms race in the region and human rights.

For the US, the EAS only makes sense if it can serve as a forum for dealing with thorny political, economic and strategic issues, putting it on a collision course with the "ASEAN way".

A more prominent US profile in regional affairs has long been sought by nations who have not been fully reassured by China's repeated insistence that its rapid rise is a peaceful one that poses no threat to the region. Face-offs with ASEAN and Japan over the Spratly, Paracel and Senkaku Islands have raised concerns about China's muscle flexing and what this portends.

Thus, a more fully engaged US is welcome as a counterweight to China, except perhaps in Beijing. But nobody wants, or gains from, a new Cold War, so the EAS represents a good opportunity for the US and China to enhance their sometimes fraught engagement while tackling problems that require collective action.

Optimists suggest that the EAS can serve to reconcile divergent interests and thrash out differences, but this may be more of a burden than summitry can shoulder. Time will tell, but the US entry can breathe life into the EAS and force it to be more relevant on issues that matter.

The EAS faces a variety of crises that give it a chance to become more robust. Recent turmoil in northern Africa and the Middle East carries implications for Asia where authoritarian governments are also facing growing public discontent over the same issues of political participation, disgruntled youth, and inflation stoked by spiking commodity and food prices.

Asian leaders have witnessed the power of the internet and the limits of repression and co-optation; delivering growth no longer ensures stability or stifles yearning for the freedoms, accountability and transparency that development nurtures. Leaders also know that growing disparities in Asian nations are a source of instability and that it is not only the poorest who are suffering from rising prices for daily necessities.

The US can usefully help shape an EAS agreement on stabilising food and commodity prices, one that acknowledges the role of global monetary easing, speculation and environmental factors, while also focusing on problems affecting procurement, distribution and production.

The EAS recognises that environmental problems are an underlying cause of conflicts, disasters and dislocations that can threaten regional peace and prosperity. Water is becoming the new oil, a resource that is spawning regional conflict and that threatens ambitious development plans. Desertification of northern China is a stark reality that is affecting industrialisation and urbanisation plans, while competition over access to the water of the Mekong River pits China against its southern neighbours.

The EAS can and should weigh in on such problems just as it needs to tackle more traditional threats to security such as competing territorial claims.

Indonesia as Chair of ASEAN and host of the 2011 EAS has an enormous task of overseeing the enlargement of the summit, managing expectations while also steering the process towards grappling with consequential issues. As a new member, the US can set a good example by making generous gestures to resolve lingering problems from the war in Indochina. Providing humanitarian medical assistance to victims of Agent Orange in Vietnam, funding research on environmental degradation and helping Cambodia and Laos to mitigate the still extensive problems of unexploded ordinance would generate goodwill and inspire the EAS to focus on problem-solving.