I know I lack clarity and legal training but I know the meaning of hubris.
You insisted that FDR did not issue an order. That is not true.
Aiiiieeee...
jwalsh07, that is the way it works! Forget about the EO for a moment and consider a regular old court martial. Congress has set forth a procedure for court martials. It has also set forth a procedure for convening one. Basically, Congress says, "Mr. Executive branch, here are the laws regarding court martials. Whenever you find someone who has broken one of our laws, you can convene one."
Back in WWII, Congress created a system for having a military tribunal in the Articles of War. The Articles also said, "The President can set this system up and start the ball rolling whenever he wishes."
That's what FDR did.