Japanese who are aliens can be brought to the continental United States from Hawaii and interned under the provisions of 50 U.S.C. § 21. This statute, however, is probably not applicable to the Japanese who are American citizens.
Although not free from doubt, an argument can be made for removing Japanese who are American citizens from Hawaii to a restricted zone in the United States on grounds of military necessity.
In view of the changed conditions of modern warfare, the Supreme Court would likely follow the views of the dissenting justices in Ex parte Milligan, sustaining a declaration of martial law in places outside the zone of active military operations upon a showing of military necessity for such action. From the nature and purpose of martial law, it would seem to be properly applicable to particular areas rather than to particular persons.