The top four surviving members of the brutal Khmer Rouge went on trial Monday before a tribunal aimed at finding justice for the estimated 1.7 million people who died in Cambodia's "killing fields" of the 1970s.
With the aging leaders all in their late 70s or early 80s and with Khmer Rouge overlord Pol Pot long dead, the trial before the U.N.-backed panel represents the last, best chance for Cambodia to bring accountability to the Khmer Rouge leadership blamed for the deaths.
All four of the defendants say they are innocent.
"This is, at this time, the most important trial in the world," said Stephen Rapp, US envoy on war crimes issues. "It's a message to others who might commit similar crimes, that there will be consequences. That it may not happen tomorrow or the next day. But eventually, you'll be in the dock as well."
During their 1975-79 reign, the Khmer Rouge tried to implement a communist utopia, but ended up killing as many as one-quarter of their countrymen through executions, medical neglect, overwork and starvation.
On trial are Nuon Chea, 84, who was Pol Pot's No. 2 and the group's chief ideologist; Khieu Samphan, 79, the former head of state; Ieng Sary, 85, the former foreign minister, and his wife, Ieng Thirith, 79, who served as minister for social affairs.
Chief judge Nil Nonn opened the court session with procedural matters, including reading out the charges against the four, which include crimes against humanity, war crimes, genocide, religious persecution, homicide and torture.
Cambodian victims' advocates have decried how long it has taken to launch the trial, saying the proceedings are needed to shed light on a dark period and that time is running out for drawing meaningful testimony from the defendants on the stand.
Although all four defendants were present for the start of Monday's session, three of them were allowed to exercise the right to excuse themselves for reason of poor health, leaving only Khieu Samphan in the courtroom.
Theary Sang, a human rights advocate representing some victims who are allowed a role in the proceedings, said it was fair to excuse the defendants because of their infirmity, but said it would be a shame not to hear their statements.
"We cannot try ghosts," Theary Sang said. "As a victim, I desire truth and justice from the defendant which is best obtained when her or she is coherent and alert."
Still, observers said the trial can play a crucial role in Cambodia's coming to terms with its past.
"There is an enormous amount to learn as the prosecutors present their case," said David Scheffer, a former U.S. envoy for war crime issues who was instrumental in helping establish the tribunal.
"And defense counsel probably will challenge evidence with their own revealing information about the defendants," he said in an interview by e-mail.
Testimony and presentation of evidence is expected to begin in August or September, 32 years after the Khmer Rouge were kicked out of power in 1979 with the help of a Vietnamese invasion.
For more than a decade afterward, they waged a bloody insurgency against the Phnom Penh government. Pol Pot escaped justice with his death in 1998, then a prisoner of his own comrades as his once-mighty guerrilla movement was collapsing.
Lawyers for the defendants came out fighting Monday, giving a hint of points they may raise later.
Lawyer Ang Udom reminded the court that Ieng Sary had been convicted and sentenced to death in absentia in 1979 by a Vietnamese-established court and that he received a royal pardon in 1996 when he led a mass defection to the government. However, the tribunal has already ruled he is still liable for charges.
Michel Pestman, representing Nuon Chea, said a full accounting of the historical context of the Khmer Rouge should include a probe of the massive wartime U.S. bombing of Cambodia and Vietnam's role.
In recent months, the tribunal has been mired in controversy over what critics charge is an effort by the co-investigating judges _ from Cambodia and Germany _ to scuttle further prosecutions. Critics have suggested the panel is folding to Cambodian government pressure to bring an end to the trials.
Cambodian Prime Minister Hun Sen, presumably wary that political allies who once served with the Khmer Rouge _ as he did _ could face prosecution, has declared he simply won't allow further indictments. He has long sought to limit the scope of the tribunal.
The tribunal started operations in 2006. Its first defendant was Kaing Guek Eav, also known as Duch, commandant of Tuol Sleng prison, where only a handful of prisoners survived. Up to 16,000 people were tortured under Duch's command and later taken away to be killed.
Duch, now 68, was sentenced to 35 years in prison for war crimes and crimes against humanity. His sentence was reduced to a 19-year term because of time previously served and other technicalities, bringing angry criticism from victims who called the punishment too lenient. Cambodia has no death penalty.