In wartime, it's enough for me -- and it was enough for the courts at the time -- that the relocations that were in fact practised should have had a rational basis. Much of the MAGIC intelligence is published in David D. Lowman, MAGIC. You can see from the evidence in that book that the relocation policy had a rational basis.
This is all something to bear in mind in our current situation.
Interesting that Chief Justice Rehnquist is apparently aware of the MAGIC evidence.