Court Ruling Against Former PM Will Haunt Thailand’s Cambodia Policy

On the night of 12 December, Thai politics entered a new phase when Prime Minister Anutin Charnvirakul dissolved the Parliament, paving the way for elections likely to be held in early February 2026. It is still far too early to predict a frontrunner. Yet despite the electoral uncertainty, Thailand’s approach toward Cambodia amid the current tensions and conflict is unlikely to become more conciliatory.

Much has been written about the roles of nationalism and electoral incentives in hardening Thailand’s stance in the current conflict. Less discussed, however, is how the Constitutional Court’s verdict against former Prime Minister Paetongtarn Shinawatra may constrain the range of diplomatic choices available to future leaders. While the ruling does not explain the origins of the current conflict, the court’s reasoning carries broader implications for the boundaries of acceptable diplomacy in Thailand’s foreign policy, especially in times of conflict.

The Constitutional Court’s intervention in Thai politics is hardly new. Since its establishment in 1997, the court has repeatedly removed political leaders and dissolved major parties, including Thai Rak Thai, the People’s Power Party, and, more recently, the Future Forward and Move Forward parties. What distinguishes the ruling against Paetongtarn Shinawatra from earlier rulings is that its reasoning extended beyond domestic political conduct into the domain of foreign policy. In dismissing Paetongtarn following her leaked phone call with former Cambodian Prime Minister Hun Sen, the court explicitly invoked “national interest” and “national prestige,” signalling not only which outcomes matter, but also the manner deemed acceptable in pursuing them. In Thailand’s deeply polarised political environment, such language can easily be weaponised, providing a basis for rival factions to accuse each other of betraying or undermining the nation.

The phone call between Paetongtarn and Hun Sen took place on 15 June, about two weeks after armed clashes in May that led Thailand to restrict border crossings and prompted Cambodia to halt imports of Thai internet services, energy, and consumer goods. In the supposedly private conversation —  later released by Hun Sen on 18 June — Paetongtarn urged him to help de-escalate tensions by reopening the border first, allowing her to avoid domestic backlash for appearing too conciliatory. Her request might have been reasonable, but the public reacted strongly to her addressing Hun Sen as “uncle.” She also said that General Boonsin Padklang, then commander of the 2^nd Army Area, was part of the “opposition”. She asked Hun Sen to relay his demands privately to her rather than posting them online. A group of senators subsequently petitioned the Constitutional Court, which ruled that the call constituted ethical misconduct. The court dismissed her on 29 August.

“ … the court has effectively narrowed the space for diplomatic flexibility in times of conflict. When nationalist emotions run high, any effort to de-escalate tensions risks being framed as a concession to an adversary and a betrayal of national pride.”

The ruling has implications for Thailand’s future foreign policy on at least two fronts, each constraining how conciliatory the country can be in times of conflict. The first concerns how the court interpreted “national interest”, and the second involves the kinds of actions it deemed inappropriate for pursuing that interest.

Although the ruling does not explicitly define Thailand’s national interest, it leaves enough clues to suggest a hierarchy of priorities. The judgment appears to place traditional security — especially military security — above economic considerations or human security. This is evident in the section addressing Paetongtarn’s intent to negotiate with Hun Sen to reopen the border, which the court interpreted not as an effort to de-escalate tensions or restore border trade, but as evidence that she prioritised Hun Sen’s concerns and her own popularity over the national interest. The ruling justified this view partly by arguing that Thailand suffered less from the border closures because Cambodia relied more heavily on Thai goods and services than Thailand on Cambodia. Such reasoning overlooks the fact that cross-border trade is vital for people living along the frontier. It also suggests that their livelihoods were not central to the court’s conception of the national interest.

What is more concerning is how the court identifies certain actions as inappropriate for pursuing the national interest. The ruling states that appealing to Hun Sen for sympathy was not a legitimate negotiating technique; rather, it was an incautious act that diminished the value and prestige of the prime minister and the nation. As the court puts it, “national prestige means the honour that is recognised by society or the international community, and the respect accorded to the nation, something that all citizens take pride in.” Such conduct, the court concluded, caused “the Thai people to suffer from a diminished sense of pride and trust in the prime minister,” amounting to a failure to safeguard the nation’s dignity and national interests.

This conclusion is extremely dangerous, as it treats public sentiment, as gauged by the court itself, as a direct measure of national prestige and then uses that connection to justify the removal of political leaders. By doing this, the court has effectively narrowed the space for diplomatic flexibility in times of conflict. When nationalist emotions run high, any effort to de-escalate tensions risks being framed as a concession to an adversary and a betrayal of national pride. Back-channel diplomacy — a routine tool of statecraft worldwide — becomes suspect simply because it is not publicly visible. Most troubling of all, the court acknowledged that at the point of Paetongtarn’s ethical misconduct, harm to the national interest had not yet occurred. It noted, however, that the mere possibility of public suspicion was deemed sufficient grounds for dismissal.

The implications of this precedent reach beyond Paetongtarn’s removal. The logic creates a potent mechanism for disqualifying future politicians whose actions diverge from prevailing public sentiment. Whoever becomes Thailand’s next prime minister, this ruling casts a long shadow over the country’s ability to pursue pragmatic foreign policy choices, particularly in its fraught relations with Cambodia.

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