Jeremy Hinzman, 26, a veteran of the US-led war in Afghanistan, appeared before Canada's Immigration and Refugee Board (IRB) to formally plead that he would face persecution if sent home to the United States.
Hinzman, who testified that comrades saw him as a "soldier's soldier", said he lived a double life in uniform, after slowly becoming aware he could not kill another human being.
"Given that I enlisted for a noble country, doing noble things, I thought, if called upon I would do it. After being trained, I realized I could not.
"I didn't have any road to Damascus moment," said Hinzman, who signed up for four years in 2001, partly to fund post-military college studies.
The South Dakota-born soldier is claiming refugee status based on his contention that he was right to refuse to fight in a war which he says was illegal and violated human rights.
He also claims he would face persecution if returned home to face desertion charges.
Hinzman first requested conscientious objector status in 2002 before learning he was to be posted to Afghanistan, where he eventually made 18 combat parachute jumps, but his application was lost.
The following year Hinzman's request was rejected, and late in 2003 he learned that he was to be deployed to Iraq, prompting him to flee to Canada early this year with his Laotian wife Nga Nguyen and two-year-old son Liam.
His case, and that of two other fugitive American soldiers, has stirred sympathy in Canada, which opposed the Iraq war.
But it has also raised fears that a positive ruling could spark a flood of US deserters across the border, as the toll of the Iraq war and occupation, which has already cost more than 1,000 US lives, deepens.
Odds against a decision favorable to Hinzman are seen as slim, however, as no such verdict has ever been handed to a US soldier here or to a combatant in a non-conscription army.
Hinzman appeared at the IRB wearing a black sweater and brown pants, still with a military-style crewcut.
He testified that his growing awareness that killing was wrong was partly born from an interest in Buddhism and attendance at Quaker religious meetings.
Outside, a knot of anti-war supporters, some waving banners reading "Let him stay," braved a blizzard to cheer as he entered the building.
Hinzman's lawyer was expected to bolster his claim during the case, which could last up to three days, by calling a US Marine Corps sergeant to detail alleged war crimes by US soldiers in Iraq.
The IRB was set up to consider the merits of refugee claims at arms length from the Canadian government.
Presiding member Brian Goodman will judge whether Hinzman would face persecution if sent back to the United States by dint of political or religious beliefs or his status as an objector to US military action.
The judgment will also question whether Hinzman will face "cruel and unusual" punishment, during what would likely be a long prison term if he was sent back to duty.
Hinzman decided to flee to Canada earlier this year after the US military denied his request for conscientious objector status in 2003 and told him he was to be deployed to Iraq.
His hopes for asylum were dented after Goodman ruled earlier this year that the question of whether the Iraq war was legal had no bearing on his claim.
WASHINGTON - Eight US soldiers on Monday sued the Pentagon, claiming the military extended their tours of duty in Iraq although their contracts had expired. It is the only known court challenge by active-duty soldiers against the defense department's so-called stop-loss policy, said attorney Staughton Lynd. One of the soldiers, David Qualls, signed a "Try One" contract in July 2003, which allows a soldier to serve for one year before deciding whether to extend service. Qualls says no one told him about the stop-loss policy. Pentagon paperwork said Qualls was on the hook until 2031, when he will be over 60 years old.
© 2004 Agence France-Presse