We were attacked, not invaded. The feds have taken full advantage of the attack to curtail as much freedom as they can. The tribunals are a bad idea from several different points of view.
As you point out, they are being implemented by decree, not by legislation.
Bush & Co. get to decide who the terrorists are (much potential for abuse there).
The precedent is a long term blow to freedom throughout our nation. The potential for abuse from a left wing dictatorial type is tremendous.
The thing to keep in perspective is that we have not been 'invaded' any more than Pearl Harbor was an 'invasion'. That renders any Constitutional support for Bush's decision shaky at best.
I consider the presence of Al Queda cells in this country an invasion. The Japanese went back to their carriers after Pearl Harbor. Al Queda is still here. And we need to react accordingly...
Dude, you don't understand. Bush can do no wrong -- he's a Republican!
(9) Prisoners of war in custody of the armed forces.
(10) In time of war, persons serving with or accompanying an armed force in the field.
As such, military tribunals will not apply to US citizens, other than those who are traitors and act in behlf of the enemy. This is not a power grab at civil liberties.
I would feel better if they were not secret, in the manner of the Nuremberg Trials. But in this case, the damning evidence, if publically revealed, may endanger the lives of agents and servicemen, may indicate the workings of classified technology used to gather it, or may tip off other provocateurs.