When an American president’s first overseas trip following his re-election is to Asia, one can be sure that something big is afoot in the region.Indeed, Barack Obama’s decision to go first to impoverished and long-isolated Myanmar (Burma) attests to the potency of the changes underway in that country – and to US awareness of China’s efforts to shape an Asia that kowtows to its economic and foreign-policy interests.Events at the ASEAN and East Asian leadership summits in Phnom Penh, the other key stop on Obama’s tour, confirmed this. At the ASEAN summit’s conclusion, Cambodian Prime Minister Hun Sen, a former Khmer Rouge commander who has ruled his country with an iron fist for three decades, closed the meeting by proclaiming that all of the leaders had agreed not to "internationalize” sovereignty disputes over islands in the South China Sea. Chinese Prime Minister Wen Jiabao, present at the summit to sign new multi-million-dollar aid agreements with Cambodia, smiled and nodded in agreement at this apparent acceptance of Chinese wishes.Not so fast, said Filipino President Benigno S. Aquino III. No such agreement had been made. Hun Sen had mischaracterized the discussions among ASEAN’s leaders.Japanese Prime Minister Yoshihiko Noda, who was also present in Phnom Penh, agreed with Aquino. At the summit’s end, Vietnam, Malaysia, Indonesia, Brunei and Singapore joined with Aquino in demanding that Hun Sen’s statement be amended. All six of these states have been pushing China to negotiate with ASEAN a multilateral process to resolve the South China Sea territorial disputes. China, dwarfing all of them, prefers bilateral talks.As Hun Sen’s behavior demonstrates, countries that are overly dependent on Chinese aid and diplomatic backing will harmonize their policies accordingly. For two decades, Myanmar behaved likewise, until Chinese overreach, particularly the now-abandoned Myitsone dam project, revealed in full the subservient relationship that China envisioned. Indeed, China’s arrogance – 100% of the power from the proposed dam was to be exported to China – was probably the key factor in precipitating Myanmar’s democratic political transition and new openness to the world.But Asians must not misconstrue Obama’s visit. Although the US is certainly undertaking a strategic "pivot” to Asia, America alone cannot construct a viable security structure for the region. From India to Japan, every Asian country must play its part.There is no alternative to this approach, because China’s rise has been accompanied by massive social and economic changes – in some instances dislocation – across the entire region. Asia’s economies have, of course, become much more integrated in recent decades, particularly through production for global supply chains. But economic integration has not been matched diplomatically. Even two of the region’s great democracies, Japan and South Korea, which have nearly identical strategic interests, have allowed an old territorial dispute – itself reflecting older unresolved animosities – to block closer cooperation.China’s prolonged – and apparently contentious – leadership transition, punctuated by the purge of Bo Xilai, suggests that its leaders’ ability to continue to manage the country’s emergence as a great power is not entirely certain. That makes the absence of a widely accepted regional structure of peace all the more dangerous.International orders emerge either by consensus or through force. The great task for Obama, incoming Chinese President, Xi Jinping, Indian Prime Minister Manmohan Singh, the new Japanese and South Korean leaders who will come to power following elections in December, and all ASEAN members is to ensure that consensus prevails in Asia without stoking China’s greatest strategic fear – encirclement.As everyone in Asia should recognize, whenever communist China has deemed that it faced such a threat, it has resorted to war – in Korea in 1950, India in 1962, the Soviet Union in 1969, and Vietnam in 1979. But fear of provoking China should not stop Asia’s leaders from seeking a regional security consensus, such as the proposed code of conduct for disputes in the South China Sea. Only the weakest of Asian states will submit willingly to Chinese hegemony – or, for that matter, to a Cold War-style US-led containment strategy.Indeed, the idea that Asian countries must choose between a Chinese or American future is false. But can Asia’s fear of hegemony and China’s fear of military encirclement be reconciled?Only a shared sense of common purpose can prevent regional militarization. Some early steps in the right direction are visible. The United States has joined several other countries in embracing a Trans-Pacific Partnership, a free-trade pact linking the Americas with Asia. Japan’s ruling party and leading opposition party are coming around to support the idea, and Obama’s invitation to China to join suggests that the US is trying to forge regional consensus where it can.For now, however, China has other ideas. It has pressed ASEAN to establish a trade zone that would include China but exclude the US and Japan.In any case, trade agreements, however beneficial, can do little to defuse Asia’s sovereignty disputes, and it is here – the greatest current source of regional tensions – that a shared common enterprise is not only possible, but also necessary if peace is to be preserved. After all, no government in the region – whether a democracy like Japan, South Korea, Taiwan, and the Philippines, a one-party state like China and Vietnam, or a tiny monarchy like Brunei – can acquiesce on such issues and hope to survive.Such diplomatic realism need not lead to zero-sum outcomes, as the example of European integration demonstrates. Just as the European Coal and Steel Community preceded today’s European Union, all of Asia would benefit from embracing shared development (without any renunciation of sovereignty claims) of the rich maritime resources that, in several cases, are fueling the sovereignty disputes.Yuriko Koike, Japan’s former Minister of Defense and National Security Adviser, is a former chairwoman of Japan’s Liberal Democrat Party, and currently an opposition leader in the Diet.Copyright Project-Syndicate.org