Japanese internment

In the early days of World War II, orders were issued by the Pacific coast military commander (lieutenant general John L. DeWitt, head of the Western Defense Command), the Governor of California (Earl Warren), and eventually President Franklin D. Roosevelt, in Executive Order 9066, for the extrajudicial detention of all persons of Japanese ancestry, whether citizens of resident aliens. Under Presidential proclamation and emergency legislation, virtually all persons of Japanese ancestry, who resided on the Pacific Coast of the U.S. mainland, were sent to detention camps.

At the same time, in the Hawaiian Islands, which had actually been attacked, U.S. Army recruiters were overwhelmed with men demanding to enlist, and the 442nd Regimental Combat Team was formed. It was sent to fight in Europe, not in the Pacific, and, for a unit of its size, had the highest proportion of awards for valor of any U.S. Army combat formation. There was some discrimination at that time; some previously denied Medal of Honor recommendations, such as to Sen. Daniel Inouye, eventually received it.

Were there cases of Japanese espionage or sabotage? Very few, usually by persons in contact with Japanese diplomats, or detected through counterintelligence or communications intelligence.

Other American soldiers of Japanese ancestry served, with distinction, as translators and intelligence analysts, as well as occasionally in combat, in individual cases in the Pacific. They generally had not lived in the designated Pacific "Western Defense Zone".