It is perhaps fitting that Asean's greatest achievement is something that has not happened. There has never been a war between two members of the Association of Southeast Asian Nations since its creation in 1967. (Southeast Asian countries, of course, have been at war during those decades but never while both sides were Asean members.)
And to gauge just how remarkable that feat is, just consider the ethnic, cultural and political diversity across the grouping. Now covering 10 nations, Asean includes the world's largest Muslim-majority nation (Indonesia), Asia's largest Catholic country (the Philippines), a constitutional monarchy (Thailand), an absolute monarchy (Brunei) as well as democracies of various shades, two of the world's remaining Communist Party-ruled states (Vietnam and Laos) and a military junta (Myanmar).
Peace then is, if not tenuous, at least fragile. Asean, long derided as a talk shop that habitually favours meetings over action, is gradually strengthening ahead of the creation of a single economic bloc by 2015, but is not bound by any formal security arrangements. Peace can never be taken for granted.
It is worth reflecting on those stakes following the violence that erupted earlier this month over the Preah Vihear temple on a disputed part of the border between Thailand and Cambodia - the worst bloodshed in years over the 900-year-old monument. Four days of intermittent fighting, including bursts of artillery fire, killed at least 10 people, left nearly 100 others wounded on both sides and forced thousands of nearby villagers to flee.
With the UN Security Council in New York due to discuss the situation overnight, it is widely hoped across the region that cool heads can prevail while the wider dispute is settled. Back in 1962, the International Court of Justice ruled that the temple proper - once part of the vast Khmer empire - is Cambodian. But the border surrounding the strategic cliff-top site has never been properly demarcated and the dispute has lingered, flaring again after the UN declared Preah Vihear a World Heritage site in 2008.
The UN meeting is a jarring reminder that Preah Vihear is resonating beyond Asean itself. China and the US have repeatedly urged restraint, reflecting their own stakes in peace on that particular border.
'Cambodia and Thailand are China's friendly neighbours,' Foreign Ministry spokesman Ma Zhaoxu said last week. 'After clashes broke out, China has maintained close contact with the two sides and has persuaded them to resolve disputes through consultation.'