In doing so, we are not unmindful of the hardships imposed by it upon a large group of American citizens. Cf. Ex parte Kawato, 317 U.S. 69, 73. But hardships are part of war, and war is an aggregation of hardships. All citizens alike, both in and out of uniform, feel the impact of war in greater or lesser measure. Citizenship has its responsibilities, as well as its privileges, and, in time of war, the burden is always heavier. Compulsory [p220] exclusion of large groups of citizens from their homes, except under circumstances of direst emergency and peril, is inconsistent with our basic governmental institutions. But when, under conditions of modern warfare, our shores are threatened by hostile forces, the power to protect must be commensurate with the threatened danger.

Like curfew, exclusion of those of Japanese origin was deemed necessary because of the presence of an unascertained number of disloyal members of the group, most of [p219] whom we have no doubt were loyal to this country. It was because we could not reject the finding of the military authorities that it was impossible to bring about an immediate segregation of the disloyal from the loyal that we sustained the validity of the curfew order as applying to the whole group. In the instant case, temporary exclusion of the entire group was rested by the military on the same ground. The judgment that exclusion of the whole group was, for the same reason, a military imperative answers the contention that the exclusion was in the nature of group punishment based on antagonism to those of Japanese origin. That there were members of the group who retained loyalties to Japan has been confirmed by investigations made subsequent to the exclusion. Approximately five thousand American citizens of Japanese ancestry refused to swear unqualified allegiance to the United States and to renounce allegiance to the Japanese Emperor, and several thousand evacuees requested repatriation to Japan