"Than your WWII model does NOT fit because we allowed Germans and Japanese to serve in our military BEFORE we defeated the radical elements in their societies."
We did NOT allow Nazis or followers of Bushido. Not known ones, at least.
You see, "Islam" isn't so much a nationality or a religion, but more akin to the militant ideologies that drove the Japanese Empire and the Third Reich.
We not let Nazis or Commies in our army just like we do not allow known terrorists or members of such groups. Just as we did allow Germans, Russians, and Japanese to fight, we do allow Muslims to fight.
BTW-Why does everyone assume that all military serve against the terrorists? If a US Muslim had concerns about fighting his fellow muslims, the US would probably let him transfer.
That is a far more logically consistent argument regarding muslims than the whole Japanese interment thing. Similarly, we don't allow members of the Communist Party to serve in the military. This is the closest approach I've seen for a legal justification to exclude muslims from Service Academies. The initiative for this, however, is going to have to come from Congress. Which means we've got a lot of work to do.