Hirabayashi v. United States (1943)

Gordon Kiyoshi Hirabayashi, a student at the University of Washington, was convicted of breaking the 8 PM – 6 AM curfew to which people of Japanese descent were subjected in "military areas" (the entire West Coast and southern Arizona) before being removed to internment camps.  The Supreme Court upheld his conviction and upheld the legitimacy of the curfew.  The court declared that "the adoption by government, in the crisis of war and of threatened invasion, of measures for the public safety, based upon the recognition of facts and circumstances which indicate that a group of one national extraction may menace that safety more than others, is not wholly beyond the limits of the Constitution."

Read the decision: http://caselaw.lp.findlaw.com/cgi-bin/getcase.pl?court=us&vol=320&invol=81