Executive Order 9066

Entering World War II: Pearl Harbor and Executive Order 9066

On December 7, 1941, Japan launched a surprise attack on Pearl Harbor and the United States entered World War II. Less than three months later, President Franklin D. Roosevelt signed Executive Order 9066 declaring parts of California, Arizona, Washington state, and Oregon a war zone operating under military rule. Despite the absence of documented cases of espionage, approximately 100,000 persons of Japanese heritage were forcibly removed from the West Coast to inland internment camps during the spring and summer of 1942. Of that number, two-thirds were U.S.-born citizens.

During the first two years of World War II, the United States sought to maintain neutrality even while aiding allies with war materials and supplemental military units. To further deter Japanese military expansion in the Pacific, the United States imposed economic sanctions on Japan—one of several factors that instigated Japan’s attack on Pearl Harbor.

On February 19, 1942, President Roosevelt signed Executive Order 9066. The order outlined the mass exclusion and incarceration of all persons of Japanese ancestry as justified by “military necessity.” The exclusion order led to the internment of Issei (first-generation immigrants ineligible for U.S. citizenship), Nisei (second-generation American citizens by birth), and Kibei (American-born U.S. citizens raised or educated in Japan) alike. Indicating the racialized nature of internment, German and Italian Americans were not subject to mass incarceration.

Following their “evacuation” from the West Coast, internees were initially placed in temporary “assembly centers” before their eventual assignment to one of ten “war relocation centers” in the interior operated by the new civilian agency, the War Relocation Authority (WRA). In Hawai‘i, internment was not implemented because the incarceration of close to 40% of the population would have crippled local infrastructure. However, community leaders were detained in one of five camps in the territory or sent to mainland WRA camps.