The 'unlawful combantant' reason for detaining the prisons at Guantanamo Bay is flawed. The Haque convention defines a legal combatant as

To be commanded by a person responsible for his subordinates;
To have a fixed distinctive emblem recognizable at a distance;
To carry arms openly; and
To conduct their operations in accordance with the laws and customs of war.

This means that both Delta Force and the CIA (the paramilitary division for sure) could be held by enemy states as unlawful combatants.