The fresh flare-up between Thailand and Cambodia does not concern border markings or disputed land around the 11th century Preah Vihear temple. The likelihood of armed deployment on either side to defend sovereignty and honour is relatively remote, so that's a comfort. Asean does not need the spectacle of an open rupture within the grouping days before it is to have its leaders' summit here with the United States, to be represented by President Barack Obama, who will be down for the Apec conference at the weekend.

But the diplomatic squabble does concern Thaksin Shinawatra, loathed by the Thai authorities as a runaway who should be serving a prison sentence on a conviction for graft but who is lionised by many Thais as a still-possible national saviour. Whether Thaksin's appointment as economic adviser by Cambodian Prime Minister Hun Sen was a calculated affront to Thailand or a real wish to tap his expertise is open to conjecture. The Thai government is furious, having no doubt about the intent and obviously seeing in the move potential for disrupting its efforts to bridge Thai class divisions. This remains an assumption.

But the fact alone is capable of entrenching the dispute in creeping emotion and irrational responses. The two nations have already downgraded relations with the recall of their ambassadors. An indiscreet remark or a rash act in such a climate can trigger reactions both nations may regret. Such was Hun Sen's suggestion made on state television that Thailand should have fresh elections, which he said he was certain the party aligned with Thaksin would win. This was unwise, an abetment in a very bad situation. Thailand should now be prepared for the likelihood that the pro-establishment Yellow Shirts and pro-Thaksin Red Shirts will resume street agitations in support of their respective agendas. Thais have seen what these activists were capable of, in bringing down elected governments and paralysing the nation.

We hope reason will prevail. Asean Secretary-General Surin Pitsuan can realistically do no more than ask the two governments to show "maximum restraint". Since he spoke at the weekend, matters have actually got worse, not better. Even if Asean had the means to settle disputes between members, this spat is essentially a random act of brinkmanship spiced with nationalist fervour and the presumed slights and arrogance of old history. The disputants have to want to work their differences through. Having their ambassadors back at their posts should be the first step.