The case made by the administration at the time was based on military security. This might appear reasonable unless one looks at the treatment of the issei and nisei in the Hawaiian Islands, where the danger of attack was much greater. Hawaiian issei and nisei, with a few exceptions, were not relocated or put in internment camps. It was decided that the economy of the Hawaiian Islands would virtually collapse if the Japanese were relocated and interned, so they remained in their homes and at their jobs throughout the war, while those on the West Coast lost their homes and businesses.
Clearly, military considerations did not control the policy. As Chief Justice Rehnquist points out, it was not military officials on the West Coast who took the lead on relocation and internment but the governor of California, Culbert Olson; the state’s attorney general, Earl Warren; and the mayor of Los Angeles, Fletcher Bowron.