Was there ever a real threat the Japanese would invade the Pacific coast during World War II? Historians think not, but with the benefit of hindsight. In 1943, however, military attorneys argued otherwise, maintaining the threat was serious and justified a racial curfew on those of Japanese descent (including Japanese Americans). These arguments helped persuade the Supreme Court, which held in Hirahayashi v. United States that the curfew was constitutional given the severity of the threat.
But did the military ever really fear a Japanese invasion? A new paper by Eric Muller suggests not. In "Hirabayashi: The Biggest Lie of the Greatest Generation," Muller presents archival evidence that "military officials foresaw no Japanese invasion and were planning for no such thing at the time they ordered mass action against Japanese Americans." Muller argues national security had little to nothing to do with the racial curfew and (worse) the government attorneys who filed the briefs in Hirabayashi knew it. According to Muller, "the Article demonstrates that the Hirabayashi decision - which has never been repudiated in the way that the more famous Korematsu decision has been, and which remains a potent precedent for race-conscious national security measures - deserves to be installed in the Supreme Court's Hall of Shame, alongside Korematsu, Dred Scott, and the Court's other biggest mistakes." He has more on the paper here.