Actions like the signing of executive order 9066 and the internment of japanese americans were most likely a result of

polices based on racist ideas

The Executive Order 9066 was enacted because many Americans, after hearing of the December 7th attack, came to distrust the Japanese Americans, and thought of them as spies, secretly sending information to mainland Japan in exchange for money, etc. The Government used Executive 9066 to "protect" the Japanese, however, the Japanese received poor housing and had the bare necessities. Later on in the war, conditions improved. 

If you want a account, read "thin wood walls"