Thailand-Cambodia: When the border flares up, what consequences await Southeast Asia?

In Southeast Asia, long cited as a model of concerted growth and regional integration, the explosion of conflict between Thailand and Cambodia has upset the fragile balance of the Indochinese peninsula. With exchanges of gunfire, deadly explosions, a flurry of diplomatic expulsions and sealed borders, the rivalry between Bangkok and Phnom Penh has now reached a level of intensity not seen since the Preah Vihear temple crisis more than a decade ago. What short-, medium- and long-term consequences will this armed confrontation have on the political, economic and diplomatic scene?

The initial shock: immediate consequences (short term)

Politics: rise of nationalism and internal stability at risk

• Populist mobilisation: The explosion of a military incident — with deaths and injuries on the front line and a state of emergency declared in several districts — galvanises nationalism in both countries. The governments, acting to avoid being perceived as weak, hardened their stance and adopted a martial tone, leading to a hardening of public opinion and between political leaders.

• Internal boomerang effects: In Thailand, already reeling from a latent political crisis, the sidelining of Prime Minister Shinawatra and accusations of mismanagement of the Cambodian issue are exacerbating divisions. In Cambodia, the wave of patriotism is being used as leverage by Hun Manet, who intends to legitimise the use of force in the face of the ‘Thai threat’.

Economy: border trade and tourism come to a halt

• Closure of border posts: The local economy on both sides is under immediate stress: marshals, Cambodian casinos, trade in fresh produce and fuel have all come to a sudden halt. The flow of goods is blocked, queues of lorries are growing and markets that are crucial for rural populations have been cut off.

• Tourism at a standstill: Already weakened by the Covid-19 crisis, hotels, drivers and restaurant owners in the border areas are seeing their revenues melt away. In 2024, the sector accounted for 12% of Thailand's GDP and 9% of Cambodia's. Fear among travellers and warnings issued by international chancelleries are leading to a wave of mass cancellations.

• Migrant workers affected: More than 500,000 Cambodians depend on jobs in Thailand. With the closure of border crossings, thousands of families are plunged into economic uncertainty.

Diplomacy: open crisis and mutual isolation

• The recall of ambassadors and expulsion of diplomats mark a near-total freeze in bilateral relations. The usual channels of dialogue have been suspended. Public diplomacy has turned into a verbal confrontation on the international stage, with each side seeking the support of third powers or multilateral bodies such as the UN and ASEAN.

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Conflict dynamics: medium-term fallout

Politics: polarisation and risks of increased instability

• Entrenchment of mistrust: As the crisis drags on, hardline positions are becoming entrenched. Civil society is under the sway of nationalist rhetoric, limiting the space for moderate voices calling for dialogue, especially in Thailand.

• Political crisis in Thailand: The conflict, weighing on the already contested Thai authorities, could be exploited by some to push for further military intervention or even a coup. The spectre of chronic instability haunts the country.

Economy: disintegration of cross-border ties and increased vulnerabilities

• Disruption of supply chains: Economic interdependence, the fruit of decades of rapprochement, is being undermined by the stalemate. Blocked transactions, suspended Sino-Cambodian infrastructure projects and regional economic corridors, and deferred investments: the net losses are mounting with each month of conflict.

• Price pressure and shortages: Cambodia, which imports 30% of its energy and many essential goods from Thailand, is experiencing shortages and imported inflation. Basic commodities are skyrocketing, further destabilising already vulnerable populations.

• Tourism devastated and image tarnished: Entire sections of the tourism sector will struggle to recover: international confidence has been shattered and the reputation for stability of both countries has been tarnished for what will hopefully only be a few tourist seasons.

Diplomacy: Asian fragmentation and weakening of ASEAN

• Regional tensions: Regional integration efforts are being undermined. ASEAN is being called upon to act but is hampered by the consensus rule and a lack of coercive leverage, illustrating chronic institutional weakness.

• Increased external interference: Faced with the inability of local actors to negotiate a way out of the crisis, due to a lack of diplomatic space or political will, external powers (China, the United States) could seek to exert greater influence, exacerbating the rivalry for influence in Indochina.

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On the horizon: long-term consequences

Politics: regional architecture under strain, a legacy of conflict

• Hardening of borders: The ‘line of fire’ could become entrenched: lasting militarisation of the border, increased incidents, rising insecurity and the transformation of the border region into a persistent risk zone.

• Erosion of mutual political capital: The trust built up between Phnom Penh and Bangkok is disappearing, jeopardising any prospect of peaceful management of territorial disputes for a long time to come. The crisis is leaving its mark on generations and fuelling mistrust.

Economy: structural losses and fragmentation of the transnational economic space

• Trade reorientation: If the crisis persists, Phnom Penh will attempt to diversify its sources of supply, turning to Vietnam or China, but at the cost of higher costs and increased dependence. Thailand, for its part, will lose an outlet in a region that was once strategic for its agricultural and industrial exports.

• Regional marginalisation: The inability to resolve the conflict undermines ASEAN's credibility as a hub of stability and integration and could slow down international investment throughout the economic corridor linking Thailand, Cambodia and Vietnam.

Diplomacy: realignment of alliances and multilateral withdrawal

• Institutional deadlock: If the standoff continues, ASEAN risks partial paralysis, with certain initiatives hamstrung by persistent rivalry between its key members.

• A bleak international outlook: For the West and the major powers, the Indochinese peninsula appears less and less like an area of opportunity and more and more like a dangerous playground, where any local crisis could escalate into a large-scale regional conflict.

The conflict between Thailand and Cambodia goes far beyond a simple border dispute. It acts as a litmus test for fragile, intertwined but rival powers struggling to break free from their sovereign reflexes and the demons of their past. Until political wisdom and regional diplomatic mobilisation regain the upper hand, the ‘line of fire’ between Phnom Penh and Bangkok will remain one of the main scars on the map of a fragile Southeast Asia.