While the legal arguments are technical, the consequences are important in terms of how the prison system treats Khadr and for his chances of a speedier release.
At issue before Alberta's Court of Appeal is whether Correctional Service of Canada has correctly interpreted the sentence handed down by an American military commission in 2010 after he pleaded guilty to five war crimes committed as a 15-year-old.
The commission — which makes no distinction between youth and adult punishment or between consecutive and concurrent sentences — ordered Khadr jailed for a further eight years.
However, in translating the sentence into Canadian terms following his transfer from Guantanamo in September 2012, Canadian authorities placed him in adult custody.
Essentially, Khadr's lawyer argues he is serving a "global" eight-year term for all five offences to which he pleaded guilty. The government argues he is serving five concurrent eight-year terms for each conviction.
While the government concedes his sentence for murder in violation for the rules of war can only be interpreted as a youth sentence under Canadian law, it insists the other four — attempted murder among them — are adult sentences.
"Canadian law recognizes that a person cannot serve both youth and adult sentences simultaneously," the government argues in its appeal factum.
As a result, it maintains Court of Queen's Bench Associate Chief Justice John Rooke was correct in siding with prison authorities that the Toronto-born Khadr, 27, should serve his time as an adult.
Khadr's lawyer Dennis Edney maintains Rooke and the government are wrong. He argues the eight-year sentence must be deemed a juvenile one.
"I've never been in a courtroom where you've had someone get a juvenile sentence for murder and an adult sentence for attempted murder all at the same (time). It just doesn't make sense," Edney said in an interview from Edmonton.
"He was a juvenile when the offence occurred and he was given a juvenile sentence and the courts should recognize that."
The prisoner was recently transferred back to the medium security Bowden Institution in Innisfail, Alta., from a psychiatric prison in Saskatoon, where he was recovering from surgery to his shoulder. Khadr, then 15, was found horribly wounded after a fierce firefight in Afghanistan in July 2002 when U.S. forces captured him.
He was accused of throwing a hand grenade that killed an American special forces soldier but maintains he only pleaded guilty before the military commission — whose very legality has been almost universally condemned — to get out of Guantanamo Bay.
The Harper government, which brands Khadr as a hardened terrorist, maintains he is being treated like any Canadian who commits a crime abroad, then transfers to Canada to serve out the sentence.
Edney said the government has gone to "all kinds of machinations" to give a rational gloss to its adult sentencing decision, but maintains there's no legal justification for the position.
"There's no way in law that you can have two proceedings at the same time giving two different sentences for two different levels in the same courtroom."