Khadr was neither charged nor convicted of treason. And he walks free today without being pursued by the authorities for treason. Clearly, your claim that he "absolutely" committed treason is not just questionable, but stretches the concept of treason far past the breaking point. A reasonable and unbiased person, taking note of all the circumstances in the matter, would not go there.

On what legal or common sense grounds do you insist that a unique situation must be adjudicated in a court of law? Unique situations are precisely the ones that do not easily lend themselves to just outcomes based on the rules of law and precedent. Ask any litigator. That's why negotiating a resolution can often be a better way.