Announcing that we were not expecting Geneva Convention protection during the conflict might have been wise, but I think there would have been great backlash for us to do the required declaration.
There is no requirement to extend Geneva Conventions POW protections to non-state terrorist groups operating on the battlefield.
Here is who is eligible for POW protections:
Art 4. A. Prisoners of war, in the sense of the present Convention, are persons belonging to one of the following categories, who have fallen into the power of the enemy:
(1) Members of the armed forces of a Party to the conflict, as well as members of militias or volunteer corps forming part of such armed forces.
(2) Members of other militias and members of other volunteer corps, including those of organized resistance movements, belonging to a Party to the conflict and operating in or outside their own territory, even if this territory is occupied, provided that such militias or volunteer corps, including such organized resistance movements, fulfil the following conditions:
(a) that of being commanded by a person responsible for his subordinates;
(b) that of having a fixed distinctive sign recognizable at a distance;
(c) that of carrying arms openly;
(d) that of conducting their operations in accordance with the laws and customs of war.
(3) Members of regular armed forces who profess allegiance to a government or an authority not recognized by the Detaining Power.
(4) Persons who accompany the armed forces without actually being members thereof, such as civilian members of military aircraft crews, war correspondents, supply contractors, members of labour units or of services responsible for the welfare of the armed forces, provided that they have received authorization, from the armed forces which they accompany, who shall provide them for that purpose with an identity card similar to the annexed model.
(5) Members of crews, including masters, pilots and apprentices, of the merchant marine and the crews of civil aircraft of the Parties to the conflict, who do not benefit by more favourable treatment under any other provisions of international law.
(6) Inhabitants of a non-occupied territory, who on the approach of the enemy spontaneously take up arms to resist the invading forces, without having had time to form themselves into regular armed units, provided they carry arms openly and respect the laws and customs of war.
Two years ago, Ralph Peters wrote an excellent column on this point, entitled "Kill, Don't Capture". Here are excerpts:
The oft-cited, seldom-read Geneva and Hague Conventions define legal combatants as those who visibly identify themselves by wearing uniforms or distinguishing insignia (the latter provision covers honorable partisans - but no badges or armbands, no protection). Those who wear civilian clothes to ambush soldiers or collect intelligence are assassins and spies - beyond the pale of law.
Traditionally, those who masquerade as civilians in order to kill legal combatants have been executed promptly, without trial. Severity, not sloppy leftist pandering, kept warfare within some decent bounds at least part of the time. But we have reached a point at which the rules apply only to us, while our enemies are permitted unrestricted freedom.
The present situation encourages our enemies to behave wantonly, while crippling our attempts to deal with terror...
Our policy toward terrorists and insurgents in civilian clothing should be straightforward and public: Surrender before firing a shot or taking hostile action toward our troops, and we'll regard you as a legal prisoner. But once you've pulled a trigger, thrown a grenade or detonated a bomb, you will be killed. On the battlefield and on the spot.
Back in the late 1970s and early 1980s, there was a proposal (Protocol I) to make multiple changes and additions to Geneva. One of these changes (Article 44) would extend POW protection to terrorists. New York Times opposed Protocol I in an editorial entitled "Denied: A Shield for Terrorists", as did the Washington Post, in its editorial entitled "Hijacking the Geneva Conventions".
As for Omar, sorry kid, you were in the wrong place at the wrong time by your own choosing. At best, you are a murderer. At worse, you are an accessory to murder. You are a terrorist, assassin, and spy. What you are not, is a soldier or a warrior. Your consequences are of your own making.