The case involved Frank Korematsu, a Japanese American man, who was convicted for defying an order to report to an internment camp during World War II. The Supreme Court upheld the exclusion order, ruling that the government's need to protect national security outweighed individual rights. The majority said the exclusion of Japanese Americans was justified by the danger of espionage and sabotage. Three justices dissented, arguing the order was based solely on ancestry and without evidence of disloyalty. The ruling established that the government could exclude and forcibly relocate people based on race during wartime.