Australian David Hicks was so desperate to get out of the Guantanamo prison that he pleaded guilty under duress to a charge that was not actually a war crime, his lawyers said in an appeal filed on Tuesday.
During his five years at Guantanamo, the man known as the "Aussie Taliban" was beaten, threatened with deadly violence, sexually assaulted, deprived of sleep for long periods and told that he would never again set foot in his native land, his lawyers said.
The former kangaroo skinner was despondent and suicidal when he pleaded guilty in March 2007 to providing material support for terrorism, they said.
The plea deal made Hicks the first person convicted in a U.S. war crimes tribunal since World War Two and allowed him to return to Australia to finish his nine-month sentence.
"When the government dangled the prospect of freedom before him, he was finally willing to drink from the poisoned chalice," his lawyers said in the appeal filed in the Court of Military Commission Review in Washington.
Hicks, now 38 and free in Australia, was captured in Afghanistan in December 2001 and was among the first group of prisoners sent to Guantanamo when the detention camp opened on Jan. 11, 2002.
Hicks has admitted he trained at paramilitary camps in Afghanistan, but said he saw no evidence of terrorism activity. The U.S. government says they were al Qaeda camps.
Hicks said he joined a group of Taliban fighters but fled his first battle, sold his gun to raise cab fare and was captured by the U.S.-backed Northern Alliance as he tried to escape into Pakistan. He said he never fought against U.S. or allied forces.
In the appeal, his lawyers argued that the Guantanamo tribunal had no jurisdiction to charge Hicks with material support and that the conviction should be thrown out because the plea deal was coerced.
"I had no choice but to sign the plea deal or I would have died in Guantanamo," Hicks said through his lawyers at the Center for Constitutional Rights.
His lawyers have said that Hicks has a good chance of winning the appeal because of a ruling last year that undermined several Guantanamo convictions.
In 2012, a U.S. appeals court in Washington ruled in the case of another Guantanamo convict, Osama bin Laden's one-time driver and bodyguard Salim Hamdan, that providing material support for terrorism was not recognized as a war crime during the time Hamdan and Hicks were in Afghanistan.
They were prosecuted under a U.S. law enacted in 2006 and the court said it could not be applied retroactively. The ruling overturned Hamdan's conviction.
A Pentagon spokesman, Lieutenant Colonel Todd Breasseale, said a federal appeals court was still reviewing the Hamdan decision and noted that Hicks had waived his right to appeal.
Hicks' lawyers said he signed the appeals waiver form during his sentencing hearing but that it was never filed with tribunal authorities and therefore is irrelevant.
If he loses in the military appeals court, Hicks could appeal to a federal appeals court and the U.S. Supreme Court.
A former Guantanamo prosecutor, among others, has said that Hicks' plea deal was orchestrated by former Vice President Dick Cheney as a favor to Australian Prime Minister John Howard.
At the time, Howard was facing a tough election, which he lost, and had been widely criticized for failing to stand up for Hicks' rights as an Australian citizen.