Why did the dispute escalate?

The border dispute between Thailand and Cambodia dates back to the early 20^th century. In 1962, the International Court of Justice (ICJ) ruled that Thailand’s claims to the territories that fell to Cambodia were unfounded (this decision was confirmed by the ICJ in 2013, after clashes in 2011). The current tensions between Thailand and Cambodia have been growing since May when a Cambodian soldier was killed in clashes with Thai forces. Following this, the two countries introduced restrictions at the border, including limiting crossings, while Cambodia suspended imports of Thai fruit. They also increased military forces at the border. In the last week, several Thai soldiers were wounded in landmine explosions, which the Thai government blamed on Cambodia (in its defence, Cambodia claims that the mines were planted many years ago). This may have been the direct cause of the escalation of tensions. Following these events, both countries downgraded diplomatic contacts, among other things. Thailand withdrew its ambassador from Phnom Penh and expelled the head of the Cambodian mission in Bangkok (all of its staff were subsequently recalled by the Cambodian authorities).

How have the clashes unfolded and what are their effects?

The clashes that began on 24 July took place in at least six locations along the disputed border. Both countries accuse the other of being the first to launch military action. The Thai air force and drones attacked military targets in Cambodia. They have also exchanged artillery fire, resulting in hits on a gas station and a hospital in Thailand, among other strikes. So far, at least 16 people have been killed on the Thai side, most of them civilians, and at least one person in Cambodia. In addition, several dozen people have been injured. More than 100,000 people have been evacuated from the border areas in Thailand and several thousand in Cambodia. The countries have not declared war on each other and the fighting is limited to the border provinces. Cambodian Prime Minister Hun Manet has called on the UN Security Council to convene a meeting on the conflict. However, both sides are already making conciliatory gestures, with Hun Manet calling on Cambodians not to discriminate against Thai citizens or companies, and Thailand’s acting prime minister, Phumtham Wechayachai, pointing to the need for balanced action in accordance with international law.

Could the dispute lead to full-scale war?

The current clashes are unlikely to escalate that far. This is indicated by several factors, including the course of the conflict so far, as well as by the calculations of the potential costs of expanding military operations. However, fighting of varying intensity may continue in the short term. This may result in heightened nationalist sentiments and a strained internal situation in both countries, among other things. Prime Minister Hun Manet has been in power for two years­—he is the son of the previous leader of the authoritarian regime, Hun Sen, currently the head of the Cambodian Senate—and he may be to build a reputation as a strong leader. Thailand, meanwhile, is facing a government crisis. Prime Minister Paetongtarn Shinawatra was suspended from her duties by the Constitutional Court in early July following the leak to the public of her telephone conversation with Hun Sen (whose families were considered to be on good personal terms). In this conversation, she allegedly pointed to a rift between the Thai government and the army, thus potentially revealing Thailand’s weakness. The actions on the border may be an opportunity for the Thai authorities and the army to present a tough stance towards Cambodia. At the same time, Thailand rejects international mediation and wants bilateral solutions.

What could be the international consequences of the fighting?

The clashes on the Thai-Cambodian border are straining stability in Southeast Asia, which is marked by other conflicts, including the civil war in Myanmar that has been ongoing since 2021 and disputes in the South China Sea, particularly between China and the Philippines. These conflicts also pose a challenge for ASEAN. Anwar Ibrahim, the prime minister of Malaysia who currently holds the chairmanship of the organisation, expressed concern about escalation of the conflict and held talks with both sides. However, the principle of non-interference by ASEAN members in the internal affairs of other states may limit its effectiveness in seeking to end the fighting and resolve the disputes. This may prompt the organisation to seek a stronger instrument for resolving conflicts between members.

China has expressed its willingness to engage in ending the conflict, which may indicate its desire to strengthen its influence in Southeast Asia, where Cambodia is one of its closest partners (ASEAN countries combined are China’s largest trading partner). It could also present itself as a mediator concerned with international peace. This would be important for China in its competition with the U.S., especially given that Thailand is one of only two treaty allies of the U.S. among ASEAN countries (the Philippines is the other). The U.S. has called for a ceasefire. It may also become involved in resolving the conflict, for example, by putting pressure on both sides in ongoing trade talks, as it did in the case of the India-Pakistan fighting in May. The European Union has called for de-escalation and dialogue. The course of the conflict may affect the EU’s relations with both countries, especially Thailand, with which the EU is negotiating a trade agreement.