Americans of Japanese ancestry

Why were Americans of Japanese ancestry incarcerated during the war? What factors were at play during the interim between the attack on Pearl Harbor in December and the decision to issue Executive Order 9066 the following February? How would you characterize the nature of confinement of Japanese Americans in the camps? How does the military service of Japanese Americans during the war complicate the history of the Internment? What are the overall implications of the Internment on American civil liberties?