Exploring ASEAN Unity During the Third Indochina War

As the disaster of the Third Indochina War unfolded, the seemingly united front of ASEAN appeared to be nothing more than a facade.

As we commemorate the 52nd #ASEANDAY, let’s take a deeper look at the narrative of unity that the regional organisation had attempted to portray during the Third Indochina War.

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On Christmas day, 1978, citing human rights abuses by the Khmer Rouge government, 13 Vietnamese divisions poured over the Cambodian-Vietnamese border, heading for several targets in Northeastern Cambodia. 

By January 1979, the capital Phnom Penh had been captured by Vietnamese troops and Vietnamese-allied Khmer rebels. A rebel government, the People’s Republic of Kampuchea (PRK), had also been set up. It was the start of a political, economic, and military confrontation that would last for over a decade.

Mr Mam Vanrith, who was a 15-year-old student when the war broke out, told The IAS Gazette: “When the Vietnamese came, I had to move to Phnom Penh. There was nothing in the city, just Vietnamese troops, but we were not allowed into the city.

“The war was a terrible time, everything was very expensive, and we used rice as money.”


Responding to the invasion and fall of Phnom Penh, the Association of Southeast Asian Nations (ASEAN) – at the time comprising Singapore, Malaysia, Thailand, Indonesia, Brunei, and the Philippines – issued a joint declaration condemning the invasion and the PRK as an unlawful result of the invasion.

While Norodom Sihanouk, the former King and Prime Minister of Cambodia, presented a case to the United Nations Security Council (UNSC) on why the PRK should not succeed the Cambodian seat in the United Nations (UN), ASEAN simultaneously lobbied for international support to deny the PRK representation in the UN and support nationalist groups, including the Khmer Rouge, in Cambodia to keep the military pressure on the PRK. 

Following years of constant effort, and cooperation with the UN, ASEAN finally brought a political settlement to the conflict, and with it, peace to the region.

According to Dr Chheang Vannarith, a public policy analyst and head of the Asian Vision Institute, he said: “ASEAN played a critical role in finding peace for Cambodia through its diplomatic engagement.

“It was regarded as the most honest mediator given the fact that ASEAN did not have the strategic ambition to build a hegemonic order in the region, just to provide a platform for dialogues and trust-building.”

ASEAN initiatives over the next decade included lobbying for and eventually creating the International Conference on Kampuchea (ICK), bringing together and supporting Cambodian nationalists under the Coalition Government of Democratic Kampuchea (CGDK), as well as designating Indonesia as the interlocutor. It eventually led to a resolution of the conflict, led by ASEAN.

Or simply the preferred narrative that the regional organisation wanted to be told.

The ASEAN version of events, under closer inspection, does not necessarily stand up to scrutiny.

The first issue was that ASEAN was not fully united in dealing with the war, or even in their understanding of the war. Different states were affected differently by the war, leading to different threat perceptions between the states. Eventually, disagreement and frustration between states.

The second and more damning criticism of the ASEAN story was that ASEAN did not really resolve the crisis. Rather, ASEAN was subject to great power politics that resolved the crisis for them, despite ASEAN claiming to be neutral.


While ASEAN states agreed that the war was a violation of ASEAN principles of non-interference and non-use of force, it disagreed in their understanding of the causes and impacts of war.

“ASEAN stood for its core values, which was freedom and peace at that point time,” said Dr Chheang.

“Fighting against communism was the political motive of the original five members of ASEAN.”

Thailand is a state sharing border with both Cambodia and Vietnam and was witnessing Vietnamese troops, a civil war, and large numbers of refugees on its borders. Thailand had a front-row seat to the spectre of expansionist communism from Vietnam over Indochina.

Singapore and Brunei, as small states who saw themselves as vulnerable to foreign incursions, saw the invasion as a violation of peace and sovereignty setting a bad precedent for violence in the region.

In contrast, Malaysia and Indonesia saw things differently. Historical ties between Vietnam and Indonesia ran strong, both having fought off colonial masters to obtain independence by blood and iron.

Malaysia, having dealt with Chinese-supported communist insurrection in the past, saw the extension of great power politics into Southeast Asia as the real threat.

The issue, therefore, was which communists they would fight – Soviet, Chinese, Vietnamese, or Khmer Rouge?

ASEAN solidarity would be further challenged because of these different views. Twice, ASEAN rejected proposals that would move the region towards conflict resolution.

First was the Kuantan Principle, where Malaysia and Indonesia proposed that Vietnam would distance itself from its patron the Soviet Union, and withdraw from Cambodia. In exchange, ASEAN would recognise a Vietnamese sphere of interest in Cambodia.

To Malaysia and Indonesia, this seemed almost natural: foreign interests would be neutralised, Vietnam would be left with an honourable settlement, and peace would be restored.

But for Thailand, Singapore, and Brunei, this was blasphemy because Vietnam, the aggressor, would not only remain unpunished for its invasion but rewarded. Without a consensus, ASEAN did not move forward on this position.

Second, was a proposal at the New Delhi Non-Aligned Summit to hold discussions between ASEAN, Laos and Vietnam. Politically, this would have allowed ASEAN to continue denying recognition to the PRK while bringing Vietnam to the negotiation table.

China, however, wanted Cambodia to be included and lobbied for Thailand and the Philippines to reject it. Once again, without a consensus, the proposal was not adopted.


Frustrated with the lack of progress and believing that an extended conflict would only serve Chinese or Soviet interests, Indonesia initiated bilateral diplomacy with Vietnam, declaring that Vietnam was not a threat and that Indonesia would not simply allow deadlock to damage its interests. This sat uneasily with ASEAN since this was not an ASEAN position.

Left with little choice and for the sake of solidarity, ASEAN made Indonesia the official interlocutor with Vietnam and agreed to integrate their dual-track diplomacy into their political strategy.

ASEAN diplomatic efforts would continue through Indonesia’s bilateral diplomacy with Vietnam, though the results had little to show. Negotiations between Jakarta and Hanoi continued until 1987, when they announced a proposal that would be known as ‘cocktail party’ diplomacy: The first stage of talks would be between the Khmer factions, before the next stage where the Vietnamese would join the talks.

Again, there was dissent from Singapore and Thailand. They viewed Vietnam’s exclusion from the first stage as tantamount to considering the war a civil war, which was unacceptable. Nevertheless, they agreed to the talks. The Jakarta Informal Meeting (JIM) was carried out in 1988, almost a decade after the war began.

However, the greatest rift in ASEAN solidarity would come from a most unlikely source: Thailand. The election of Chatichai Choonhaven in Thailand led to a complete reversal of the Thai position on the issue.

Under General Prem Tinsulanonda, Thailand had been a hardliner in ASEAN, relentlessly lobbying for a resolution to the conflict and refusing to accept PRK control over Cambodia. Chatichai, however, took a different approach, declaring that he wanted to turn Indochina from a battlefield into a marketplace.

More significantly, ASEAN had refused to recognise the PRK government until Chatichai. The newly minted Prime Minister of Thailand had simply ignored the prior consensus and invited Hun Sen, the head of the PRK government and the present Prime Minister of Cambodia, on an official state visit.

A move that “unilaterally undermined a decade of ASEAN diplomacy” and was criticised, according to International Relations in Southeast Asia: The Struggle for Autonomy, authored by Donald E. Weatherbee, a former Visiting Professional Fellow at the ISEAS – Yusof Ishak Institute.


The end of the crisis, however, was not to be directed by ASEAN, but by the great powers. All of whom had stakes in the conflict. Dr Shankari Sundararaman, a professor of Southeast Asian Studies and ASIA Fellows Award recipient, in an article for the Institute for Defence Studies and Analysis, pointed to two key issues that the great powers agreed on that allowed negotiations to proceed to a peace deal:

First, the US agreed to engage Vietnam directly to prevent the return of the Khmer Rouge. Secondly, China stated that it would not seek a dominant role for the Khmer Rouge in a political settlement.

This agreement formed the foundation for a series of negotiations between the Permanent Members of the UNSC. In 1991, the Agreements on a Comprehensive Political Settlement of the Cambodian Conflict were signed, and the UN Transitional Authority in Cambodia was set up to implement the agreements.

Throughout the conflict, ASEAN’s positions shifted and was pulled in opposing directions by its own member states. Why then, does the narrative exist that ASEAN was cohesive and effective?

In his journal article Saving Face in Diplomacy: A Political Sociology of Face-to-Face Interactions in ASEAN, Dr Deepak Nair, a professor in Southeast Asian relations and ASEAN diplomacy, explained that “managing disagreement meant managing audiences: disagreement was openly expressed only at “caucus meetings” involving ASEAN members while a firm taboo operated over expressing disagreement before foreign (and) non-member diplomats and representatives.”

ASEAN, in other words, participated in an exercise of face saving throughout the challenges of international diplomacy. Rather than being a cohesive group with a common goal, ASEAN states were often at odds with each other. While they may not have achieved their goals in the way they imagined, they at the very least, managed the façade of doing so. 

But perhaps Dr Felix Tan, associate lecturer of International Relations and Foreign Policy Analysis at SIM Global Education, describes ASEAN disunity best: “As far as nations within ASEAN tries to be as unified as they can be, each have their own national interests.”

Although ASEAN was created with the purpose of economic development and to resolve domestic and regional security concerns, it must be noted that each member has their own unique history, each quite different from the other. 

As such, it would generally give the international community that ASEAN is not unified in their goals,” added Dr Tan.

“An organisation such as ASEAN would need to manage such differences the best they can.”

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