Border clashes between Thailand and Cambodia that caused dozens of casualties and displaced thousands have challenged the Association of South East Asian Nations (ASEAN) to finally turn its rhetoric on peace and security into action. Cambodia’s successful attempt to list the Preah Vihear temple as a World Heritage Site came against the backdrop of turmoil in Thai politics after the 2006 coup that deposed Prime Minister Thaksin Shinawatra. Thai pro-establishment movements used this issue to whip up nationalist sentiments against Cambodia as they tried to topple the Thaksin-backed government. The emotionally-charged campaigns halted border demarcation and sparked a bilateral conflict. In early 2011, the dispute turned into the most violent clash yet between ASEAN’s members, testing its historical commitment to non-aggression and prompting it to get involved. This has raised expectations that it might live up to its stated aspiration to keep peace in its own region. As yet, however, while its engagement set important precedents, it has no significant achievements. More robust diplomacy and leadership are still needed.

The resurgence of a largely forgotten 50-year dispute into an active armed conflict was related to two events: the colour-coded struggle in Thailand between the pro-establishment “Yellow Shirts” and the pro-Thaksin “Red Shirts” sparked after Thaksin’s ouster in the September 2006 coup; and the decision of Cambodia to register Preah Vihear as a World Heritage Site, which UNESCO accepted in July 2008. In Cambodia, the listing was occasion for national joy and Khmer pride. In Thailand, the ultra-nationalist Yellow Shirts used it to argue that Thaksin’s proxy administration led by Prime Minister Samak Sundaravej had sold out their motherland and committed treason. It became a powerful weapon to further their agenda, forcing the foreign minister to resign and destabilising the government. They successfully portrayed backing for the listing as a move to further Thaksin’s business interests, despite this policy having been supported by the previous military-installed administration. Until the Yellow Shirts’ attacks, bureaucrats on both sides had seen the listing as a mutual tourism bonanza.

The frontier became increasingly militarised and tense. Border survey and demarcation ground to a halt, as it became too dangerous to field joint teams. At the same time, political turmoil in Thailand led to a high turnover of foreign ministers and other senior officials. Nationalist lawsuits, controversial court rulings and constitutional provisions hamstrung the efforts of officials to negotiate and poisoned the bilateral relationship. Frustrated by this inaction and these obstructionist tactics, Cambodia’s prime minister, Hun Sen, often lashed out and on one occasion appointed Thaksin as an adviser – an episode that was the political low point of a troubled period.

Despite the warning signs between 2008 and 2010, passivity rather than active peacemaking was the “ASEAN way”. After the outbreak of hostilities in 2011, the UN Security Council set a precedent by referring the issue back to ASEAN and its then chair, Indonesia, which showed how energetic and bold leadership could bring the association closer to what [some of] its supporters wished it might be. ASEAN broke more new ground after both sides agreed to receive teams of Indonesian observers to monitor a ceasefire.

Thailand’s civilian leaders initially agreed to the deployment but backtracked after its military resisted, claiming the observers would undermine sovereignty, a sign that the post-coup struggle for power is unresolved. Cambodia approved them in May, but Indonesia would not dispatch its monitors until both sides signed on. The election of Yingluck Shinawatra as Thailand’s prime minister in July 2011 was expected to be a turning point, but was not. Even a ruling by the International Court of Justice (ICJ) that ordered the creation of a provisional demilitarised zone around the temple and called on ASEAN to monitor a troop withdrawal did not remove political obstacles. Then in October, Thailand was crippled by the worst flooding in living memory, leaving the government overwhelmed. With the waters now subsiding, Thailand and Cambodia need to recommit to complying with the ICJ decision as soon as possible.

ASEAN aimed to stop hostilities and restart negotiations when it took up the border issue in early 2011. While there has been no fighting on the border since May, the ceasefires in place are mostly verbal and unsigned. Until troops are verifiably withdrawn and diplomats resume negotiations, this conflict is not over. But in trying to resolve it, ASEAN, under Indonesia’s leadership, has laid out a methodology for dealing with future disputes. If it wants to fulfil its stated goal of taking responsibility for its own peace and security, it needs to use its existing mechanisms at the first sign of trouble and not just rely on an activist chair. The Thai-Cambodian conflict remains an active challenge for ASEAN, which must achieve a certifiable peace on this disputed border if it wishes to keep its own region secure in the future.

Bangkok/Jakarta/Brussels, 6 December 2011