(CN) - The 9th Circuit upheld a life sentence without parole Tuesday for the man who led a failed coup attempt against Cambodia's authoritarian prime minister in 2000.
Yasith Chhun, christened the "Cambodian Moses," emigrated to the United States after the brutal Khmer Rouge regime fell in the late 1990s. Under the Khmer Rouge, millions of Cambodians died from execution, disease and starvation. Chhun became a tax accountant in Long Beach, Calif.
When Cambodian prime minister Hun Sen, a former field commander of the Khmer Rouge, staged a coup in 1997 and took power, however, Chhun established the Cambodian Freedom Fighters to unseat Sen.
The group staged a November 2000 attack on government buildings in Cambodia's capital, nicknamed "Operation Volcano," which Chhun organized from Thailand.
Several rebels and one innocent bystander were killed in the attack before the government sent in tanks to quell the uprising.
The government of Cambodia later issued an Interpol warrant for Chhun's arrest.
He was convicted in U.S. courts in 2008 of conspiring to overthrow the Cambodian government, and sentenced to life without parole.
In upholding that conviction Tuesday, a three-judge panel of the 9th Circuit noted that "it is not absurd for Congress to want to prevent people within the borders of the United States from plotting to commit murder in a foreign country."
Chhun argued that he intended to arrest not kill Hun Sen, and that he planned Operation Volcano to minimize casualties.
Evidence entered at trial, however, showed that Chhun had the "intent to murder," according to the 26-page opinion.
In a letter, Chhun wrote supporters that his enemies "are lucky to survive at this moment, but however they can not escape from our volcano. We have to send them to ... hell in the near future," the court found.
Chhun also sent a handwritten military plan that instructed rebels to "look for surviving enem[ies] very carefully... [and] take prisoners or shoot to kill on the spot."
Therefore, "there was sufficient evidence in the record to allow the jury to conclude that Chhun had the intent to murder his enemies when he conspired to overthrow Hun Sen," Judge Carlos Bea wrote for the court.
Even though diplomatic relations between the U.S. and Cambodia were "distant and tense" after Sen's coup, "no case has held that the United States can cease to be 'at peace' with another nation with the complete absence of some kind of military operation," of either an overt or covert nature, the court found.
Bea also upheld Chhun's life sentence.
"The sentencing court also explained that illegal conduct will not be shielded from punishment just because it is 'noble,'" Bea wrote. "The court rejected Chhun's pleas for leniency because he caused the deaths of innocent people. These reasoned justifications for sentencing Chhun to life in prison show that the sentence was not substantively unreasonable."