It is, but one has to be an unlawful combatant or a member of a foreign military organization in conflict with the US to be subject to military tribunal. Committing treason is not enough.
How about these:
1. Member of Muslim Brotherhood or assiasting MB?
2. A non-citizen posing as a citizen? And doing the above?
If the DS is structured as supposed with foreign masters, how else would you characterize those in this country who have supported the war on their behalf and waged it here as anything but unlawful combatants?