Post-Pearl Harbor created the greatest single mass incarceration of American citizens in history. Starting with the 1942 executive order 9066 by President Roosevelt, more than 110,000 JapaneseAmericans from California, the western portions of Washington and Oregon, and a small part in Arizona were relocated to assembly and relocation centers. Often given less then 48 hours to pack Japanese Americans were forced to either sell or dispose off any items that they could not carry (Matray, James I.)
The responsibility of rounding up Japanese Americans fell on the shoulders of the US army, but by late 1942 all responsibility was headed by the War Relocation Authority, with military provided security for guard towers and around the camps.
Primary sources such as these posters show the requirements the Japanese Americans faced in the relocation process. American citizens feared that the Japanese Americans would chose the side of the enemy and aid in espionage. Time magazine at the time wrote, "They could distinguish the 'kindly, placid, open'" faces of the Chinese to the 'positive, dogmatic, arrogant' faces of the Japanese." (Matray, James I).
47,000 Issei or native born Japanese first to immigrate to America were deprived of U.S. Citizenship but their 70,000 American born children or Nisei were citizens (Matray, James I). These citizens along with their parents were forced into assembly or relocation centers. According a Californian congressmen Leland Ford," Any patriotic native born Japanese, if he wants to make his contribution, will submit himself into a concentration camp." Despite having committed no crime at all any Japanese person was declared an enemy (Matray, James I).
After the war anti-Japanese discrimination and racism was minimal. The most extreme anti-Asian violence was the 1982 murder of American born Vincent Chin in Detroit. The Chinese decedent was killed with a baseball bat and was a case of mistaken identity as his attackers thought he was Japanese ("Japanese Americans").