He also has apparent populist appeal. A poll of Cambodians taken in December 2011 by the International Republican Institute — the international democracy-promoting arm of the U.S. Republican Party — found that 81 percent of some 2,000 respondents said Cambodia is "generally headed in the right direction."
Lao Mong Hay, an independent political analyst in Cambodia, thinks the secret to his success is simple: "Who dares, wins. He dares and he wins."
But many critics say that too often what Hun Sen dares to do is use brute force and manipulation of the courts to maintain his hold on power.
"Hun Sen's violent and authoritarian rule over more than two decades has resulted in countless killings and other serious abuses that have gone unpunished," New York-based Human Rights Watch said in a recent report. Labor organizers, politicians, journalists and environmentalists have been among those who have died violently over the years.
Human rights groups fear Obama's visit will be seen within Cambodia as an affirmation of the prime minister and a sign to opposition groups that the U.S. stands with the government, not with them.
For all that, many Cambodians still credit Hun Sen with dragging their country out of the abyss into which it had fallen under the Khmer Rouge. The communist regime came to power in the 1970s and engaged in a systematic genocide that left 1.7 million dead in its attempt to create a pure agrarian society. By the time Vietnam invaded in 1979 to oust the regime, Cambodia was a broken shell of a country: every social, political and cultural institution was in ruins.
Born to a peasant family in east-central Cambodia, Hun Sen initially fought with the Khmer Rouge against a pro-American government. He lost an eye in combat. But he defected to Vietnam in 1977 and accompanied the Vietnamese invasion. By 1985, he had been named prime minister.