Friends turned Foes

Hun Sen’s betrayal of the Shinawatras reignites tensions on the Thai-Cambodian border, exposing the fragility of personal diplomacy and the unfinished business of history.

It began, as it often does in Southeast Asia, with a mine and a leak. Five Thai soldiers were maimed by an explosive buried near the tangled, disputed border with Cambodia. By the following day, at least 15 civilians - mostly Thai - were dead while diplomatic ties had unravelled. Cambodia’s once-durable backchannel to Bangkok, forged through decades of Shinawatra diplomacy, lies in tatters. The proximate cause was a leaked phone call. The deeper reason lies in centuries of mistrust and the opportunism of two political dynasties playing for high stakes at home.

Relations between the two neighbours have always been uneasy. Their 800-kilometre border, carved by colonial cartographers and made murky by jungle and war, has been the site of recurrent skirmishes. The worst in recent memory came in 2008 and 2011, when artillery duels near the ancient Preah Vihear temple killed over 40 soldiers and civilians. Back then, saner heads prevailed quickly. But not this time.

The spark came in June when Hun Sen, Cambodia’s wily ex-premier and de facto regent to his son, Prime Minister Hun Manet, published a phone call between himself and Thai Prime Minister Paetongtarn Shinawatra. In the call, Paetongtarn, Thaksin Shinawatra’s daughter, called him “uncle” and disparaged one of her own military commanders. The leak ignited nationalist fury in Thailand, embarrassed the Thai armed forces, and all but doomed Paetongtarn’s premiership. She has since been suspended, and the constitutional court is weighing her dismissal.

Why would Hun Sen sabotage a relationship that once served him well? The Shinawatras and Hun Sen go way back. When Thaksin was deposed by a coup in 2006, Cambodia offered him sanctuary. When his sister Yingluck suffered a similar fate in 2014, Phnom Penh again provided a safe haven for red-shirt loyalists. The rapport between the two political clans blurred the line between diplomacy and family ties, often bypassing formal institutions altogether. In 2020, Thai dissidents in Cambodia began disappearing - abducted, it was believed, by Thai agents with at least tacit Cambodian assent. Cambodian opposition figures, too, met grim ends on Thai soil.

Now that fragile pact has crumbled. Thaksin, newly returned from exile and weakened politically, could not shield his daughter from the fallout. Thai police have since begun probing Cambodian tycoons with ties to illicit online gambling and scam networks that Cambodia’s post-pandemic economy has come to rely on. Trade between the two countries has ground to a halt. Bangkok has expelled Cambodia’s ambassador and withdrawn its own. Hun Sen, in turn, has threatened to release documents allegedly proving that Thaksin insulted Thailand’s monarchy.

This personal falling out has escalated into a geopolitical crisis. Thailand’s ruling coalition is brittle and preoccupied with an economic slowdown and looming US tariffs. Paetongtarn’s suspension is only the latest blow. Cambodia, too, faces economic headwinds. Chinese tourists remain scarce, frightened off by horror stories of forced labour in scam compounds. Both nations desperately need stability. Neither is showing the maturity to deliver it.

That responsibility once fell to ASEAN, the ten-member regional bloc founded in 1967 with the express aim of preventing conflict between Southeast Asian neighbours. But ASEAN, perennially allergic to confrontation, has yet to intervene in any meaningful way.

Yet the strangest piece of this puzzle remains Hun Sen himself. The man who long played regional peacemaker has now set fire to a personal relationship that once defined Cambodia-Thailand diplomacy. Some speculate that Thailand’s crackdown on scam centres may have ruffled powerful interests in Phnom Penh. Others believe Thaksin’s bid to legalise gambling in Thailand threatens Cambodia’s own casino-driven economy.

Perhaps the answer is simpler. Hun Sen is nothing if not a survivor. Having handed power to his son, he may be seeking to bolster his own legacy as a nationalist stalwart. Burning Thaksin - no longer a kingmaker in Thailand - may cost him little and win him domestic plaudits. A calculated betrayal has once again put Hun Sen at the centre of regional intrigue.