The offer was one of two proposals Khadr's lawyers put to military commission authorities in 2008 in hopes of avoiding a trial. The convening authority rejected both out of hand.
In the first proposal, Khadr's Pentagon-appointed lawyer at the time, Lt.-Cmdr. Bill Kuebler, called on Washington to ask Canada to "investigate and charge" his client under the Criminal Code offence of participation in the activity of a terrorist group.
The basis for the charge would have been video showing Khadr as a young adolescent helping make improvised explosive devices in Afghanistan.
"The defence believes sufficient evidence is currently available...to initiate charges," Kuebler wrote in the proposal dated July 18, 2008.
Under the proposal, Khadr would then have pleaded guilty in a Canadian court either via videolink or through a lawyer, followed by transfer to Canadian custody within 45 days.
The proposal called for a sentence of between nine and 18 months in custody — including a stint at an "appropriate rehabilitative facility" such as the Centre for Addiction and Mental Health in Toronto.
He would also have been subject to a three-year period of probation, including restrictions that he not live with his mother or sister in Toronto.
Now 25, the Toronto-born Khadr also would have given up appeal rights and waived any damages claims against the U.S. or Canada.
Kuebler attempted to sell the deal as "advantageous" to the United States, arguing it would avoid a legal fight over the fact that Khadr was 15 years old when he committed the crimes with which he was charged.
"As a former child soldier, Mr. Khadr has a strong legal challenge to the jurisdiction of the military commission," Kuebler wrote.
"It is abundantly clear that Congress did not intend military commissions to exercise jurisdiction over juvenile defendants."
Prosecuting Khadr by military commission was also "inconsistent" with American obligations under the Optional Protocol to the Convention on the Rights of the Child, the lawyer wrote.
Kuebler argued the case against Khadr for throwing a grenade that killed a special forces soldier was "extremely weak." No one witnessed the throwing, and the on-scene commander wrote after the incident that the person responsible had been killed, the lawyer noted.
Like many others, Kuebler also questioned the validity of the charge — murder in violation of the law of war — a crime most legal observers outside the commission process don't recognize.
Commission authorities responded by saying they had no jurisdiction to enter into such a plea agreement.
Kuebler tried again two months later, with similar results.
In September 2008, he proposed that Khadr would admit to being "part of a group of al-Qaida operatives who engaged in U.S. military and coalition personnel with small-arms fire and grenades, killing SFC Christopher Speer, two Afghan militia force members and resulting in numerous injuries to coalition personnel."
In exchange, Khadr was to receive a maximum nine-year sentence, minus time served in custody since his capture in Afghanistan in July 2002. Transfer to a Canadian prison would have occurred within 30 days of sentencing.
The convening authority rejected the proposal without giving reasons, but encouraged further negotiations.
In an agreement essentially written by the prosecution, Khadr finally pleaded guilty in October 2010 to all five charges he faced — including murder in violation of the law of war. In return, he was sentenced to a further eight years in custody, with only one to be served in Guantanamo Bay.
Ottawa's subsequent delay in allowing his transfer to a Canadian prison to serve out his sentence as per the plea deal has drawn fierce criticism from Khadr's supporters and others who argue the government is riding roughshod over his rights as a Canadian citizen.
Kuebler, who was fired as Khadr's lawyer in April 2009, refused to discuss the proposed deals.