Three general causes of the Japanese American evacuation are examined. Collective disposition considers the antagonism toward immigrants, special characteristics of California politics, economic competition, segregation and racial stereotypes, and Japanese American international relations as conditions which instituted a persistent anti-Japanese attitude on the West Coast. Situational factors include the tendency to suspect treachery of all Japanese following Pearl Harbor and the time pressures which curtailed deliberation by government officials on the evacuation question. Collective interaction considers the interaction among the main elements which produced the evacuation decision. A short section describes the relocation centers and the evacuees' reaction to detention.