Lasting Thai-Cambodian truce never been more urgent

The failure on both sides to take the diplomacy path will be disastrous.

A permanent ceasefire between Cambodia and Thailand is not a diplomatic option anymore.

It is the final barrier between a controllable border crisis and a prolonged war in mainland Southeast Asia.

Once BM-21 rocket salvos and naval shelling become habitual, escalation acquires its own momentum – detached from politics, detached from restraint, and increasingly detached from reason. That is why Dec 22, 2025 matters.

When ceasefire talks reconvene in Kuala Lumpur under Malaysia’s Asean chairmanship, it may be the last window before artillery exchanges are normalised. Kuala Lumpur cannot impose outcomes, but it can prevent paralysis.

Declaring that failure is unacceptable does not eliminate the risk of failure. But failure truly is not an option – humanitarian, political, or regional.

Humanitarian costs are already acute. Close to half a million people combined from both sides have been affected.

Border communities have evacuated. Cross-border livelihoods have collapsed. Trading posts are paralysed. Schools and farms are emptying under the threat of shelling and mines.

Political fragility magnifies risk. Bangkok is governed by a caretaker arrangement sensitive to nationalist posturing; Phnom Penh refuses to signal weakness under pressure. Neither will concede easily when political survival depends on avoiding humiliation.

Regional credibility at stake

If Asean cannot arrest violence on its own soil, “centrality” becomes an empty diplomatic slogan. A region that manages global summits but cannot stabilise its own borders loses strategic influence.

Yet the structural incentives on both sides favour breakdown rather than restraint.

Thailand has issued three conditions:

• A unilateral Cambodian ceasefire,
• A continuous and sustainable ceasefire, and
• Demining of contested terrain.

All sound reasonable in diplomatic syntax. None is workable in military logic.

A unilateral stand-down means revealing artillery positions, forfeiting initiative, and risking encirclement.

No actor firing BM-21 saturation rockets will abruptly fall silent while the other side retains momentum.

For Phnom Penh – defined by historical trauma and elite pride – unilateralism equals humiliation.

A “continuous and sustainable” ceasefire is rhetorical comfort without verification.

Sustainability requires observers, reporting channels, and agreed upon punitive provisions. Without them, every incident becomes an accusation, and every accusation becomes grounds for retaliation.

Malaysia’s proposal for an Asean observers team reflects a basic truth: ceasefires without verification collapse into recrimination.

Just as valid, verification cannot function if observers operate on sufferance.

That is why the Asean Observers Team (AOT) must be granted secure, predictable, and sustainable access to border zones, not episodic clearance dependent on the daily political moods in Bangkok or Phnom Penh.

An observer mission that cannot enter cannot report, and when it cannot verify, it cannot restrain escalation.

AOT, therefore, requires more than ceremonial presence. It needs:

• Guaranteed physical access to contested terrain,
• Protected mobility corridors,
• Communications that cannot be obstructed, and
• Legal assurances that its personnel will not be targeted, detained, or denied movement.

This demands military-to-military agreements that remove observer safety from the discretionary authority of field commanders, preventing local provocations and partisan loyalties from sabotaging the process. Equally important, AOT capacity must match battlefield complexity.

If current numbers prove insufficient, the pool of defence attachés – those with operational literacy, clearance discipline, and experience with artillery doctrine – must be expanded.

A small civilian liaison cell cannot keep pace with BM-21 batteries, naval platforms, rotating battalions, and explosive-ordnance hazards.

AOT requires an inner sanctum of military observers capable of reading radar signatures, mapping salvo trajectories, and interfacing credibly with both armies.

This is not militarising diplomacy. It is professionalising verification.

Without it, “ceasefire monitoring” becomes a performance theatre rather than a restraining mechanism, and both militaries will continue operating under the cover of ambiguity.

Demining is equally fraught. Presented as humanitarian, its effect is territorial. Mines secure defensive depth in areas of uncertain sovereignty.

Whichever side removes mines first exposes itself to incursions and tacitly endorses the other side’s map. In border dispute environments, mines are not merely weapons; they are leverage. Phnom Penh sees unilateral demining as unilateral surrender.

What both capitals want is superficially compatible: Bangkok wants momentum halted and optics stabilised; Phnom Penh wants parity and respect.

But both fear exploitation. Malaysia’s task, therefore, is not to “declare” a permanent ceasefire; it is to help them engineer one with the presence of US and China which they had agreed to. Even Japanese defence attaches are involved.

Engineering requires sequence, symmetry, verification, and buffers. It requires preparing for diplomatic wobble.

Malaysia must anticipate nationalist rhetoric. It must anticipate spoilers, including informal military-business networks that benefit from confrontation.

Cambodia’s most prominent spoiler remains former prime minister Hun Sen, whose “shadow command” still shapes military incentives and elite behaviour.

Preparing for failure is not pessimism; it is resilience-cum-realism.

The Thai and Cambodian conflict is an extremely serious one. Asean did not mismanage it. Asean has always wanted the two sides to overcome their differences when flashpoints occured time and again in 2008 and 2011.

It’s unfortunate that it has ruptured into a serious border war in the latter half of 2025.

Malaysia cannot compensate for Asean’s non-interference reflex unless both sides genuinely want peace. Nor can Kuala Lumpur mediate effectively – even with the support of the US and China – if Bangkok and Phnom Penh treat diplomacy as theatre.

Thus military-to-military coordination across all combatants and facilitators matters – not to choreograph combat, but to avoid radar, drone, or satellite misreads.

Both sides have already agreed to utilise US satellite intelligence to map troop movements and shelling patterns. That step must be institutionalised.

Humanitarian logic must follow:

• Corridors, evacuations, shared operating procedures, and mutually recognised safe zones.

These are not moral gestures; they create shared incentives to avoid war crimes and civilian mass casualties.

• Economic stabilisation must come next.

Silence becomes cooperation only when revenue flows return, markets reopen, and supply chains resume. De-escalation must be economically rewarding, not merely militarily convenient.

• Independent verification separates allegation from fact.

Social media narratives in Cambodia alleging the execution of 18 captured soldiers were defused only when the International Committee of the Red Cross verified their survival. Without verification, rumours become triggers.

• No ceasefire is “naturally” permanent.

Permanence is constructed through supervision, reciprocity, and deterrence. It requires simultaneous – not unilateral – stand-downs. It requires mapping rather than ambiguity.

Asean cannot absorb another frozen conflict.

It is already paralysed by Rakhine in Myanmar. The South China Sea remains militarised.

Southern Thailand simmers. Even the Aceh settlement risks stress after catastrophic flooding killed more than 1,000 people across Sumatra in November 2025.

Normalising artillery duels between Cambodia and Thailand would corrode the idea of Asean as a security community and reduce regional leadership to commentary. The stakes exceed Preah Vihear or Sisaket.

They test whether Southeast Asia can discipline its own battlefield. They test whether Asean can impose structure on violence. Malaysia’s success will not come from optimism.

It will come from designing mechanisms that prevent breakdown from becoming irreversible.

That is why failure of a permanent ceasefire between Cambodia and Thailand is not an option – because the alternative is regional decay. - FMT

The views expressed are those of the writer and do not necessarily reflect those of MMKtT.