Lt. General John L. DeWitt, leader of the Western Defense Command, believed that the civilian population needed to be taken control of to prevent a repeat of Pearl Harbor.
To argue his case, DeWitt prepared a report filled with known falsehoods, such as examples of sabotage that were later revealed to be the result of cattle-damaging power lines.
DeWitt suggested the creation of the military zones and Japanese detainment to Secretary of War Henry Stimson and Attorney General Francis Biddle. His original plan included Italians and Germans, though the idea of rounding-up Americans of European descent was not as popular.
At Congressional hearings in February 1942, a majority of the testimonies, including those from California Governor Culbert L. Olson and State Attorney General
Earl Warren, declared that all Japanese should be removed.
Army-directed evacuations began on March 24. People had six days notice to dispose of their belongings other than what they could carry.
Anyone who was at least 1/16th Japanese was evacuated, including 17,000 children under 10, as well as several thousand elderly and handicapped.
Japanese internment camps were established during World War II by President Franklin D. Roosevelt through his Executive Order 9066. From 1942 to 1945, it was the policy of the U.S. government that people of Japanese descent, including U.S. citizens, be incarcerated.
www.history.com