Justice Black wrote the opinion of the Court:
The petitioner, an American citizen of Japanese descent, was convicted in a federal district court for remaining in San Leandro, California, a “Military Area”, contrary to Civilian Exclusion Order No. 34 of the Commanding General of the Western Command, U.S. Army, which directed that after May 9, 1942, all persons of Japanese ancestry should be excluded from that area. No question was raised as to petitioner’s loyalty to the United States. . . .
It should be noted, to begin with, that all legal restrictions which curtail the civil rights of a single racial group are immediately suspect. That is not to say that all such restrictions are unconstitutional. It is to say that courts must subject them to the most rigid scrutiny. Pressing public necessity may sometimes justify the existence of such restrictions; racial antagonism never can. . . .
Executive Order No. 9066, 7 Fed. Reg. 1407 . . . issued after we were at war with Japan, declared that “the successful prosecution of the war requires every possible protection against espionage and against sabotage to national-defense material, national-defense premises, and national-defense utilities. . . .”
One of the series of orders and proclamations, a curfew order, which like the exclusion order here was promulgated pursuant to Executive Order 9066, subjected all persons of Japanese ancestry in prescribed West Coast military areas to remain in their residences from 8 p.m. to 6 a.m. As is the case with the exclusion order here, that prior curfew order was designed as a “protection against espionage and against sabotage.” In Kiyoshi Hirabayashi v. United States, we sustained a conviction obtained for violation of the curfew order. The Hirabayashi conviction and this one thus rest on the same 1942 Congressional Act, [56 stat. 173, 18 U.S.C.A. §97 (a)], and the same basic executive and military orders, all of which orders were aimed at the twin dangers of espionage and sabotage. . . .
Here, as in the Hirabayashi case, we cannot reject as unfounded the judgment of the military authorities and of Congress that there were disloyal members of that population, whose number and strength could not be precisely and quickly ascertained. We cannot say that the war-making branches of the Government did not have ground for believing that in a critical hour such persons could not readily be isolated and separately dealt with, and constituted a menace to the national defense and safety, which demanded that prompt and adequate measures be taken to guard against it.”
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 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. . . .
We uphold the exclusion order as of the time it was made and when the petitioner violated it. Compulsory 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.
[The Executive orders issued contained three separate provisions.] These separate requirements were that those of Japanese ancestry (1) depart from the area; (2) report to and temporarily remain in an assembly center; (3) go under military control to a relocation center there to remain for an indeterminate period until released conditionally or unconditionally by the military authorities. Each of these requirements, it will be noted, imposed distinct duties in connection with the separate steps in a complete evacuation program. . . .
Since the petitioner has not been convicted of failing to report or to remain in an assembly or relocation center, we cannot in this case determine the validity of those separate provisions of the order. It is sufficient here for us to pass upon the order which petitioner violated. . . .
Korematsu was not excluded from the Military Area because of hostility to him or his race. He was excluded because we are at war with the Japanese Empire, because the properly constituted military authorities feared an invasion of our West Coast and felt constrained to take proper security measures, because they decided that the military urgency of the situation demanded that all citizens of Japanese ancestry be segregated from the West Coast temporarily, and finally, because Congress, reposing its confidence in this time of war in our military leaders—as inevitably it must—determined that they should have the power to do just this. There was evidence of disloyalty on the part of some, the military authorities considered that the need for action was great, and time was short. We cannot—by availing ourselves of the calm perspective of hindsight—now say that at that time these actions were unjustified.