BANGKOK, Thailand -- In a spectacular and dangerous political breakup between Asia's two most powerful de facto leaders, Cambodia's Hun Sen publicly ended his "betrayed" friendship with Thailand's Thaksin Shinawatra and, in revenge over their deadly border dispute, said Mr. Thaksin allegedly duped Bangkok's judicial authorities by wearing a neck brace and arm sling as fake props to avoid prison.

Cambodian Senate President Hun Sen livestreamed his bombshell allegations which shocked Thais and sharply increased the political vulnerability of Bangkok's teetering coalition government headed by Mr. Thaksin and his daughter, Thai Prime Minister Paetongtarn Shinawatra.

"Now that I’ve been betrayed, I feel I must reveal what the Thaksin family did to betray their nation," Mr. Hun Sen said on June 27 at a local government meeting.

Directing his anger and allegations at Mr. Thaksin, Mr. Hun Sen warned: “If you act arrogantly, I will expose everything you told me.

"Discipline your children. You have a child as prime minister, and I have a child as prime minister. But don’t mistake me for someone you can cross.

“I regret that a 30-year friendship was destroyed by a friend's daughter," Mr. Hun Sen said, referring to Ms. Paetongtarn.

Mr. Hun Sen's official Facebook page, which has 14 million followers, is also filled with anger, accusations, and dismay about Mr. Thaksin and his daughter.

Their surprise breakup began when Thailand and Cambodia became embroiled in a brief clash, which killed a Cambodian soldier on May 28 along their disputed frontier in the jungle and scrubland of the Emerald Triangle where eastern Thailand, northern Cambodia, and southern Laos meet.

Both sides blamed each other for politicizing the feud and whipping up aggressive nationalism, which escalated throughout June into border closures and boycotts of imports and exports, despite the supposedly deep personal friendship between the two nations' dynastic ruling families.

"All I want is an equal relationship built on mutual respect, with no encroachment and no intervention," Mr. Hun Sen said, referring to their border feud. 

Each side blames the other for initiating hostilities on the frontier.

The twice-elected Mr. Thaksin, who will be 76 years old in July, is one of Thailand's most powerful civilian political leaders.

He is widely perceived as ruling this Southeast Asian, Buddhist-majority, U.S. treaty ally through his pliant 38-year-old daughter, Ms. Paetongtarn.

Thai media describe Mr. Thaksin as the "de facto boss of the Pheu Thai Party" which is officially led by his daughter atop an uneasy ruling coalition which includes pro-military parties.

Mr. Hun Sen, 72, was one of Pol Pot's anti-U.S. Khmer Rouge regiment commanders during the 1970s and, after defecting to Vietnam, became Cambodia's authoritarian prime minister for 38 years.

In 2023, he orchestrated his son Mr. Hun Manet, 47 and a West Point graduate, to become the country's current prime minister.

"I flew to Bangkok to visit Thaksin. He was not ill at all," Mr. Hun Sen said describing events last year.

"When it came time to take [media] photos, he asked for props -- a neck brace, an arm brace -- to appear unwell. As soon as the photos were done, he removed them and went to dine," he said, according to the conservative Bangkok Post's translation of Mr. Hun Sen's Khmer language livestream.

"That's not illness, that's theater. Thai people already have suspicions. I am only confirming what many have thought, because both Thaksin and his daughter, Paetongtarn, are acting in bad faith," Mr. Hun Sen said in his meeting with local Cambodian government officials.

Thai politicians, investigators, and the media suspected Mr. Thaksin, who voluntarily returned to Thailand in 2023, avoided being confined to a jail cell by allegedly faking severe illness, enabling him to spend months in a hospital before being released.

He had been sentenced to several years in prison, later pardoned down to only one year, for financial corruption committed during his 2001-06 administration.

A government photograph of Mr. Hun Sen meeting Mr. Thaksin and Ms. Paetongtarn on Feb. 21, 2024 in Bangkok shows the two men sitting on a sofa next to each other with Mr. Thaksin's neck swathed in a thick wraparound circular medical neck collar and a reinforced black sling on his right arm, with refreshments on the table in front of them.

Mr. Thaksin had also appeared in Thailand at events while wearing what appeared to be the same neck brace and arm sling, including when he was sitting next to a swimming pool.

Thais filled social media with criticism and mocking memes about those appearances, because they were convinced he was faking illnesses for leniency in several pending court cases.

In 2006, Mr. Thaksin was toppled by the U.S.-trained military in a bloodless coup and stayed overseas for 15 years dodging prison sentences for financial corruption during his administration.

Based mostly in Dubai, the fugitive arranged for his sister Yingluck Shinawatra to be elected prime minister in 2011 as another pliant political proxy, but her government was ousted in a 2014 military coup. 

Ms. Yingluck is currently in self-exile, sometimes in England, dodging prison sentences for financial mismanagement involving her government's rice subsidies.

While Mr. Thaksin avoided being caught in Thailand, Mr. Hun Sen named him as an "adviser" to Cambodia's government and openly appeared to be personally supportive.

In his livestream, Mr. Hun Sen claimed Ms. Paetongtarn allegedly confided her plans when she maneuvered against one of her coalition government's political rivals.

"Even when you planned to remove Anutin Charnvirakul [on June 19] from his posts as deputy prime minister and interior minister, you told me," Mr. Hun Sen said.

"If you can betray your own citizens, why would you not dare betray me? Of course you would."

Meanwhile, more than 10,000 anti-Thaksin, pro-military protesters gathered in Bangkok's grimy streets at Victory Monument on June 28 demanding Ms. Paetongtarn resign because of her seemingly cringing phone call to Mr. Hun Sen on June 15 which was leaked, including her disparaging criticism of Thailand's Second Army Region Commander Lt. Gen. Boonsin Padklang.

Lt. Gen. Boonsin's forces guard northeastern Thailand's entire border with Cambodia, including the disputed Emerald Triangle where the Cambodian soldier was shot dead.

In the audio of her leaked call -- which she later confirmed -- Ms. Paetongtarn told Mr. Hun Sen that she did not want him "to listen to the opposing side, especially since the [Thai] Second Army Region commander is entirely from the opposition.

“He [the Thai commander] just wants to appear cool or impressive. He may say things that are not beneficial to the country,” Ms. Paetongtarn reportedly said in Thai to Mr. Hun Sen's translator during her call.

As a result of her telephone remarks, Ms. Paetongtarn faces Bangkok's politically powerful Constitutional Court on July 1 when it is expected to decide if it will accept a petition claiming she violated the constitution, threatened Thailand's security and must be ousted, signed by 36 pro-military senators.

If the court accepts the case, she could be removed immediately or be allowed to remain as a caretaker prime minister while the court hears her case, which could take several weeks or months.

"The judges will assess whether [her] continued occupancy of the premiership, even for a day or two, could pose a credible risk," legal scholar Jade Donavanik told the Bangkok Post.

"If there is a reasonable suspicion that such a risk exists, then remaining in office would be untenable," Mr. Jade said.

Ms. Paetongtarn's next test comes two days later on July 3 when she faces a no-confidence vote in parliament where she has a slim majority after pro-military Bhumjaithai (Proud to be Thai) Party leader Anutin Charnvirakul quit her coalition government and moved his 69 parliamentarians into the opposition.

The National Anti-Corruption Commission, the Election Commission, and the Central Investigation Bureau are separately due to also hear allegations that her conversation with Mr. Hun Sen may have violated the constitution and threatened Thailand's security.

During Saturday's (June 28) street demonstration, the protesters did not explicitly call for a coup, but some indicated they would support a putsch if Ms. Paetongtarn refused to resign.

“If the military wants to do something during a national crisis, go ahead, but let the selection of the prime minister involve public participation,” said prominent protest leader Sondhi Limthongkul.

In 2008, Mr. Sondhi led pro-military, royalist Yellow Shirt supporters to shut down Bangkok's two international airports, stranding tens of thousands of travelers for more than a week, in a protest to topple Mr. Thaksin's brother-in-law Prime Minister Somchai Wongsawat.

The royalist anti-Thaksin leader of the Thai Pakdee Party, Warong Dechgitvigrom, told protesters: “We are facing a prime minister with the DNA of a traitor, while our soldiers protect national sovereignty."

"I filed a complaint against Hun Sen under Thai law," because the Cambodian leader recorded and leaked an official call, said Somkid Chueakhong, deputy secretary-general to the prime minister for political affairs.

"The next step is for the case to proceed as a special investigation. After the investigation, it will be submitted to the attorney-general.

"If Hun Sen fails to appear, a summons will be issued, followed by an arrest warrant," Mr. Somkid said.

Richard S. Ehrlich is a Bangkok-based American foreign correspondent reporting from Asia since 1978, and winner of Columbia University's Foreign Correspondents' Award. Excerpts from his two new nonfiction books, "Rituals. Killers. Wars. & Sex. -- Tibet, India, Nepal, Laos, Vietnam, Afghanistan, Sri Lanka & New York" and "Apocalyptic Tribes, Smugglers & Freaks" are available at
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