The 1944 Supreme Court decision (which a few judges dissented with, thankfully) is a frightful read:
"To cast this case into outlines of racial prejudice, without reference to the real military dangers which were presented, merely confuses the issue. 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."The case was reopened in the 1980s, and Mr. Korematsu's conviction was overturned in a 1984 US District Court decision. The conclusion of Judge Patel in that decision is excellent:
"As historical precedent it [the Korematsu case] stands as a constant caution that in times of war or declared military necessity our institutions must be vigilant in protecting constitutional guarantees. It stands as a caution that in times of distress the shield of military necessity and national security must not be used to protect governmental actions from close scrutiny and accountability. It stands as a caution that in times of international hostility and antagonisms our institutions, legislative, executive and judicial, must be prepared to exercise their authority to protect all citizens from the petty fears and prejudices that are so easily aroused."