Presidential Executive Order 9066 was signed by President Franklin D. Roosevelt in February of 1942. This law allowed for the placing of Japanese American citizens into internment camps during World War II.
FDR did this just a couple short months after the Japanese military bombed the US military base at Pearl Harbor. FDR did this as he was worried that some of these Japanese American citizens were spies for the Japanese government. However, this act would be recognized decades later as a clear violation of the rights of Japanese American citizens.