SURIN PROVINCE, THAILAND: After his daughter was sidelined from political office by a damaging phone call with Cambodia’s leader this month, Thai power broker Thaksin Shinawatra broke his silence to a roomful of politicians and journalists. He had a stunning message to deliver: His decades-long relationship with Cambodian strongman Hun Sen was over. “I used to be close to him – like brothers,” Thaksin said. “But after what he did to my daughter, I was shocked. How could this even happen?”For years, many had believed that the personal relationship between Thaksin, 75, and Hun Sen, 72, would be the glue holding the two neighbors together despite an border dispute. Both were among Southeast Asia’s most seasoned politicians, bound by a friendship spanning 33 years and by their shared dynastic ambitions, with children who were elevated to power within a year of each other.Now, a rift has opened up between the two men, bewildering even Thaksin himself and shocking insiders. And the fallout has been severe, with Thai and Cambodian troops exchanging fire in the deadliest clashes in over a decade. Analysts say they worry that the animosities could spiral out of control.Hours after fighting began Thursday, Thaksin and Hun Sen lobbed insults at each other on social media. Thaksin said many had offered to mediate but that he wanted to “let the Thai military do their duty to teach Hun Sen a lesson about his cunning ways first.”Hun Sen fired back at Thaksin on FB while referring to himself in the third person: “Now, under the pretext of taking revenge on Hun Sen, he is resorting to war, the ultimate consequence of which will be the suffering of the people.”Analysts say Hun Sen has sought to exploit the turmoil within the Thai govt to shore up his own legitimacy. Even opposition figures in Cambodia have taken the govt’s side, arguing that the disputed temples that lie along the border belong to the country. A crisis may solidify the nationalist credentials of Hun Manet, the current prime minister and Hun Sen’s son, who has implied that Cambodia’s one-party rule is better than the domestic chaos in Thailand because there is “no confusion or conflicting orders.”The political standing of Thaksin, a billionaire tycoon, and his ruling Pheu Thai party have both weakened since he struck a deal with the royalist-military establishment in 2022 to end 15 years of exile, alienating his core supporters. For decades, Thaksin and Hun Sen worked to anchor their personal and political fortunes together. In 2001, they signed a memorandum of understanding to pursue the extraction of oil and gas in the Gulf of Thailand. But that plan fizzled because of resistance from Thaksin’s rivals.Hun Sen and Thaksin remained close even after Thaksin was ousted in a 2006 coup. Hun Sen appointed Thaksin as an economic adviser to the Cambodian govt, and allowed him and his sister, Yingluck, who was also overthrown in a coup, to seek refuge in his home in Cambodia. Hun Sen later said he named the bedrooms the “Thaksin room” and the “Yingluck room.”