OTTAWA - Omar Khadr would likely never face conviction in Canada even if there was a way to charge him with an offence under Canadian law, legal experts who advocate his repatriation acknowledge.
The legal opinions up the ante in the raging public debate between those who want the former child soldier returned to Canada and those who say he should face American military justice.
University of British Columbia law professor Michael Byers, a noted international law expert and would-be federal NDP candidate, is one of many who want the Toronto-born Khadr released from the U.S. military prison in Cuba.
Khadr, the only westerner being held at Guantanamo Bay, could be tried under Canada's War Crimes Act, argues Byers.
Others say Canada could use its anti-terrorism legislation - currently being tested in the bomb-plot trial of Momin Khawaja - as the mechanism for prosecution north of the border.
But that doesn't mean Khadr, who was 15 years old when he was captured by U.S. forces in Afghanistan, would be convicted - or even held in custody.
"I think the fact that he was a juvenile is likely to exculpate him completely," said Byers, UBC's Canadian Research Chair in International Law and Politics who recently announced his intention to seek election under the New Democratic Party banner.
The real balancing act, he said, is the "challenge to rehabilitate him and to reintegrate him into Canadian society in a way that is respectful of both his rights and also . . . the rights of Canadians to be protected against people who may constitute something of a danger.
"It's only, however, a balance we can achieve if we have him back on Canadian soil."
Prime Minister Stephen Harper has steadfastly refused to intervene in the case, insisting Canada has "no real alternative" but to follow a U.S. military tribunal's proceedings against Khadr.
The Toronto-born 21-year-old was captured by U.S. soldiers following a bloody firefight in Afghanistan in 2002. He is alleged to have thrown a grenade that killed U.S. Special Forces Sgt. Christopher Speer.
Accused of murder, Khadr also faces charges of attempted murder, conspiracy and supporting terrorism.
Khadr's lawyers have argued in U.S. federal appeals court that he is being held illegally, because international law bars governments from detaining juveniles as enemy combatants and prosecuting them for war crimes.
But U.S. government lawyers, in a filing Friday with a district appeal court, countered that the military has the authority on the battlefield to capture and detain anyone, at any age, accused of attacking and killing American soldiers.
The court is scheduled to hear arguments in the case Sept. 4.
Advocates for his release from U.S. military custody say Khadr should be dealt with in a regular court system and treated as a child soldier, not as an "unlawful enemy combatant" as the U.S. describes him.
Many want him tried in Canada.
But Khadr's legal circumstances are unique, argues Michael Newton, a law professor at Tennessee's Vanderbilt University. Newton doesn't see how the set of facts in Khadr's case could even translate into a chargeable offence under the War Crimes Act.
"Canadians would probably not view Khadr as having committed a war crime within the meaning of the Act," Newton recently told the CBC.
A University of Ottawa legal research report, however, suggests he could be tried through this country's anti-terror laws.
"Through the anti-terrorism legislation, because of its extraterritorial jurisdiction, we can definitely try him under that provision," said Ajmal Pashtoonyar, one of the report's authors.
Nonetheless, Pashtoonyar also suggested Khadr would likely never be convicted.
Canadian prosecutors would have to consider that confessions made by Khadr may be inadmissible in court due to allegations of mistreatment, including weeks of sleep deprivation, before he was interrogated.
As it stands, Khadr faces trial before a U.S. military commission in October. If the case proceeds as expected, he'll become the first child soldier to be tried for war crimes since the Nuremberg trials against the Nazis.
All opposition parties in the House of Commons have recently called on the Harper government to insist on Khadr's release from Guantanamo Bay into Canadian custody.
Byers argued that even if Khadr could not be tried under current Canadian law, the Conservative government cannot stand behind what he termed the "flimsy" excuse of an absence of legislation to warrant keeping Khadr in U.S. military custody.
"If there was a legislative impediment or an absence of legislative basis for doing anything with regards to Khadr, that could very easily be fixed," he said.
"I don't anticipate that there would be any problem if the government wanted to ask for special legislation to accommodate his circumstances."
With so many questions surrounding detainees at Guantanamo Bay and Khadr's legal status in limbo, it's uncertain where his case will end up, say the legal experts.
There has been speculation that detainees at Guantanamo Bay could be moved to the United States, but still be handled by a military commission system.
The U.S. presidential election this November is another wild card.
Both Republican John McCain and Democratic candidate Barack Obama have indicated they'd like to shut down the Guantanamo military prison.
