President Obama’s cancelation of his trip to participate in next week’s ASEAN and APEC Summits next week has the internet abuzz with discussion of what it may mean for America’s role in the Western Pacific. Initial reactions, however, are not necessarily good indicators. President Obama cancelled trips to Indonesia and Australia three times in 2009-2010. The Bush Administration’s attention to personal diplomacy in Southeast Asia was likewise spotty.

Yet, within the region, at least, all was forgiven with the advent of America’s “Asia Pivot.”

The substance of the pivot is one thing. It is under-resourced on the military side and the economic component – the Transpacific Partnership FTA – is complicated by a Democrat caucus in the House that is overwhelmingly and demonstrably protectionist. This is beginning to sink in a bit in the region. The appeal of the pivot narrative, however, has proven remarkably resilient.

If the pivot weathers another major cancellation – and it almost certainly will – one has to start asking why. The reason is because Southeast Asia needs America. Call it an insurance policy or balancing or hedging, or what you will, ASEAN does not want to be left alone with China. And no combination of other outside players is as reassuring as the United States’ presence.

As Secretary of State John Kerry prepares to sit in for the President in next week’s meetings with ASEAN leaders, he ought to fully absorb the meaning of this. The U.S. is in a strong position, particularly on the contested issue closest to American interests – the South China Sea.

He would also be well-advised to take a look back at a seemingly unrelated corner of ASEAN history to understand what’s really going on there on this issue.

Cambodia in the 1980s was one of the great and tragic battlefields of the Cold War. With Soviet support, communist Vietnam invaded in 1978. It toppled one of the great scourges of mankind, the regime of the Khmer Rouge, and replaced it with a Vietnamese-puppet regime. Almost immediately, the Chinese entered the conflict, seeking to stem Soviet influence in the region. Local resistance emerged, and, suddenly, Southeast Asia was back on the front line of the Cold War.

The Association of Southeast Asian Nations (ASEAN) had refrained from criticizing the murderous Khmer Rouge – not wanting to interfere by making moral judgments. But the new Vietnamese-Soviet-backed regime was different; it posed a direct threat. Three countries--Singapore, Thailand and the Philippines—mobilized to oppose and reverse Vietnam’s aggression.

Indonesia and Malaysia saw it differently. Indonesian and Malaysian leaders convened in a Malayisan town named Kuantan. As Southeast Asia scholar Amitav Archarya recounts, they came up with a bargain: ASEAN should recognize Vietnam’s interests in Cambodia in a political settlement of the conflict; in exchange, Vietnam would distance itself from the Soviet Union. Thus, would ASEAN restore peace and keep greater powers at bay.

The “Kuantan Doctrine” as it became known collapsed two months later, in June of 1980, when Vietnamese troops pursuing Cambodian resistance forces crossed into Thai territory. ASEAN consequently affirmed its demand for total Vietnamese withdrawal. Singapore, Thailand and the Philippines – with an assist from the Vietnamese-installed government in Cambodia – prevailed. ASEAN, the U.S., and China stepped in to help the Cambodian resistance, and in 1989, Vietnam withdrew its troops. Vietnam was admitted as a member of ASEAN in 1995, and Cambodia was admitted in 1999

All is well that ends well. (Mostly well – Hun Sen, the Prime Minister of Vietnam’s puppet government in Cambodia, remains in power today.) But this brief history offers a lesson of immediate importance about the way ASEAN operates.

In 1980, Indonesia and Malaysia were prepared to sell off both Thailand’s interest as a front line state and the related concerns of Singapore and the Philippines. Indonesia and Malaysia’s interests were more abstract. Their priority was to assure the long-term preservation and expansion of ASEAN and to keep outside powers from interfering. Addressing their fellow ASEAN members’ concern about Vietnam was not on their agenda.

Something similar is happening today regarding the conflict in the South China Sea. The People’s Republic of China, backed by record-setting growth in defense spending and deployments of naval and other maritime assets, is asserting a claim to the vast majority of the South China Sea – right up to the shore line of the Philippines. This time, it’s primarily the Philippines, but also Vietnam, that find themselves offered up as sacrifice for the greater ASEAN good.

And this time, the argument for accommodation of the outside aggressor is carrying the day. It is doing so in the form of infinite patience with Chinese diplomacy. For 20 years, ASEAN has appealed to international law as the basis for managing and settling the territorial dispute in the South China Sea. Yet, when the Philippines appealed to arbitration under the UN Convention on the Law of the Sea (UNCLOS), its ASEAN partners went silent. This despite the fact that they are all signatories

ASEAN has fallen back on unending negotiations over a code of conduct to bind parties to the conflict. And the U.S.—aside from encouraging quicker diplomacy—is going along. This, even as China demonizes and attempts to isolate the Philippines for standing up for its sovereignty.

Make no mistake. If a binding code-of-conduct is ever concluded it would be a major accomplishment. But it is not going to happen on its own. And it’s not going to happen without a more active, forceful U.S. policy. Left to its own, ASEAN cannot deal with the problems in the South China Sea.

It is time to use the leverage apparent in ASEAN’s interest in the U.S. presence to give it some backbone in dealing with China.

During his upcoming meetings in Brunei, Secretary Kerry should bring back the Administration’s more assertive tone of 2010 when Secretary Clinton laid down the law on the South China Sea in Hanoi. Indeed, the Administration should take it one step further. Instead of soliciting ASEAN’s careful advice on how to handle interaction with China, it should should press ASEAN to take tougher public stands and, specifically, to support the Philippines’ case. Instead of accepting limited-joint military exercises among the ASEAN countries, U.S. and China as part of the ASEAN Defense Ministers Plus and other region-wide ASEAN-centered mechanisms, the U.S. should press ASEAN to exclude China from exercises until it gets serious about resolving the problem. As leverage, the U.S. can use its own participation.

For years now, ASEAN members have warned the U.S. not to ask it to choose because we might not like how it chooses. Sufficiently warned, the Obama Administration refrains – ceding initiative to an organization whose record at managing disputes beyond its borders is dismal. But ASEAN does not have as many alternatives as it pretends. Sometimes leadership means asking friends and allies to do difficult things. If that’s a choice, so be it: ASEAN should choose. A code of conduct is only going to succeed by shutting down China’s options to simultaneously engage ASEAN on the code and reinforce its maximalist position. The U.S. can help ASEAN do this by better playing the dynamics within ASEAN.

The blogosphere will settle down on President Obama’s cancellations. Doubts in Southeast Asia about America’s staying power will certainly remain. They have been there for at least 40 years. However, there are several other more fundamental realities that remain: US interests in the region, China’s rise, and ASEAN’s need for America’s reassuring presence – and divisions within ASEAN. All need to be taken sufficiently into account in the effort to secure American national interests.

Editor’s note: When this piece was first posted, the President had only partially cancelled his trip. It has been updated to reflect subsequent developments.

-Walter Lohman is director of The Heritage Foundation’s Asian Studies Center.