The 65-year-old is now the world’s sixth longest-serving civilian leader, bumped up a place by last month’s fall of Zimbabwe’s Robert Mugabe.
And his grip on the country is stronger than ever, as the brash premier extinguishes rivals and fortifies his family’s control over the poor nation.
In a religious ceremony for “peace and stability” in early December, the premier prayed beneath Angkor Wat — the Khmer empire’s most glorious monument and a symbol of power and continuity.
The event was choreographed to show Hun Sen as the pivot point of a nation that is now effectively a one-party state after the main opposition party was dissolved by the Supreme Court.
“Hun Sen needs a halo… which he creates by drawing on mythology. It’s artificial,” opposition leader Sam Rainsy told AFP from France where he now lives in self-exile.
“He is a dictator… and dictators often rely on a cult of personality.”
Hun Sen vowed last month to hold on to office for at least 10 more years, but batted away comparisons to Mugabe who served into his 90s.
But critics say the Cambodian premier is cut from the same cloth and is going to increasingly great lengths to secure his monopoly on power.
Hun Sen’s Cambodian People’s Party (CPP) will in effect be unopposed at elections next year after Rainsy’s Cambodia National Rescue Party (CNRP) was disbanded and its parliamentary seats and local posts redistributed.
The opposition had been tipped for power after making big gains in 2013 elections, but Hun Sen methodically picked off its leaders with legal cases before the Supreme Court delivered the knock out blow in November.
Scores of opposition MPs have fled the country, while a crackdown on critical media and civil society has earned a rebuke from Washington.
But the streets remain clear of protests.
Analysts say that reflects public fear of courts and security forces closely allied to Hun Sen.
But it may also reveal a reluctant acceptance among the young, pro-democratic population that their best bet is stability and economic growth while Hun Sen holds the aces.
– The Hun Sen Family –
Though he resists succession talk, Cambodians have long suspected Hun Sen is building a dynasty.
His three sons are prominent in public life and the apparatus of government.
The eldest, 40-year-old Hun Manet, is seen as the most likely successor.
A graduate of West Point military academy in the United States, he is a deputy commander in both Cambodia’s army and the elite Prime Minister’s Bodyguard Unit.
His second son, General Hun Manit, heads up military intelligence.
The youngest, Hun Many, 35, is a CPP parliamentarian who oversees its far-reaching youth movement and has openly expressed a desire to lead.
The sons are not just likely heirs, but also strategic tethers to Cambodia’s elite.
A 2016 report from the NGO Global Witness detailed how Hun Sen and his progeny have built up business empires that stretch across the economy — and help buttress his political fortress.
Hun Sen’s sons either declined to be interviewed or did not respond to requests from AFP.
The ruling party is also tight-lipped on a long-term strategy.
“We have plans, but if I reveal them, it violates the principles of the party congress” which designates the prime minister, said CPP spokesman Sok Eysan.
– The Party and China –
Hun Sen was not born into power himself.
The son of peasant farmers, he started out as a cadre in the genocidal Khmer Rouge regime but later defected to Vietnam and returned with that country’s invading forces.
He was installed as prime minister in 1985 and outlasted his Vietnamese benefactors, who left the country in 1989.
From the early 1990s he engineered a facade of multi-party democracy supported by the United Nations, keen to endorse a semblance of stability following the horrors of the Khmer Rouge.
Since then he has used his CPP party as a patronage network.
The party boasts five-million paid up members, nearly a third of the population and a youth movement that spans the country.
“Hun Sen controls Cambodian politics through a tight mesh of personal relationships that binds together the CPP, leading tycoons, and the senior echelons of the security forces,” said Sebastian Strangio, the author of a biography of Hun Sen.
Underpinning his winning streak is Cambodia’s economic revival.
Pump-primed by China, the economy this year is chugging along at almost seven percent.
By the end of 2016, Chinese direct investment totalled $11.2 billion, according to official Cambodian data.
Chinese companies are driving a construction boom, from mega-dams to highways and casinos targeting Chinese punters.
Hun Sen is a regular visitor to Beijing, where he is lavished with soft loans without any censure on his demolition job on democracy.
That “no strings” support has emboldened his attacks against critics in politics, the media and Western democracies like the US — who he once needed for financial support.
Cambodia’s future now appears wedded to its new benefactor.
“China will continue to offer support to ensure Cambodia stay politically stable and economically sound,” said political analyst Meas Ny.
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