Canadian Omar Khadr is about to become the first child soldier to be tried for war crimes since the Nuremberg trials against the Nazis.

A military judge in the United States has given the go-ahead to a military commission to prosecute the child soldier for war crimes. He has been languishing in a jail cell in the internationally-condemned U.S. prison at Guantanamo Bay, Cuba, since he was 15-years-old.

As U.S. military prosecutors get set to prosecute the Canadian, his case was kicked around like a political football in Ottawa.

Domestic and international observers -- including Canadian and European human rights activists and legal organizations -- have been pressing Prime Minister Stephen Harper to repatriate Khadr for years.

Liberal Leader Stephane Dion on Wednesday demanded to know why the government has not called for the Canadian citizen's return like other Western nations have with their citizens.

"It's the freedom of a Canadian citizen that's at stake," Dion said during question period in the House of Commons.

"Why is the prime minister refusing to demand the return of a Canadian citizen?"

Harper's response to questions about the child soldier's fate was similar to answers he has been given about his government's handling of election tactics, environmental policies, and bureaucratic issues -- he said the previous government was no different. Harper said the Liberals did not do anything to help Khadr when they were in power.

"The only thing that has changed is that in 2006 Canadians changed governments," Harper said.

Harper said Khadr, who was taken by his father to war-torn Afghanistan as a child, faces serious charges.

Deputy Liberal Leader Michael Ignatieff brought up the case of Abousfian Abdelrazik, a Canadian on a no-fly list because of alleged ties to terrorists who is stuck in Sudan. His family has said he is not a terrorist and wants Canada to help bring him home. Internal government documents suggest that even some foreign affairs officials say "it's unethical" to leave the Canadian in a legal limbo.

Ignatieff suggested that the Conservatives are picking and choosing which Canadians they want to help overseas.

Last week, Brenda Martin, who was convicted in connection with a fraud scheme in Mexico, was brought home to Canada on a private jet. She was allowed to serve her time in a Canadian prison after several top-level officials in Ottawa -- including the prime minister -- spoke with their Mexican counterparts.

Khadr, now 21, is the only remaining Western prisoner at Guantanamo Bay. Canada, unlike other Western nations who had citizens detained there, has not pushed to have Khadr returned home.

Khadr was captured in 2002 following a firefight with U.S. Special Forces. He was brought to the country by his father, who had ties to al Qaeda and was killed in Pakistan in 2003. The Pentagon maintains Khadr threw a grenade during the fight, killing a U.S. soldier.

"No part of this story is true," his lawyer U.S. navy Lt.-Cmdr. William Kuebler told a parliamentary committee in Ottawa last month.

He was a "frightened, wounded 15-year-old boy" during his capture, Kuebler said.

He said Khadr was then shot twice in the back by a U.S. soldier and would have been summarily executed on the spot had another soldier not intervened. Kuebler has also said that the U.S. has doctored evidence against the Canadian.

He noted he does not think that the Canadian government should punish Khadr for the sins of his father.

Kuebler said international protocol establishes that soldiers under 18 cannot be considered voluntary participants in armed conflict. He said the protocol has established that child soldiers should receive "rehabilitative rather than punitive sentences."

Khadr is expected to appear again in a military court Thursday. His lawyers are trying to obtain documentary evidence about the case from the prosecution.