Japanese-American Incarceration

Summary

Following President Franklin D. Roosevelt's Executive Order 9066 of 19 February 1942, the U.S. government forcibly removed approximately 120,000 people of Japanese ancestry — roughly two-thirds of them U.S. citizens — from the West Coast and detained them in ten inland camps administered by the War Relocation Authority. A 1983 federal commission concluded the incarceration was not justified by military necessity.

What Happened

Ten weeks after the attack on Pearl Harbor, President Franklin D. Roosevelt signed Executive Order 9066 on 19 February 1942, authorizing military commanders to designate areas from which “any or all persons” could be excluded. Acting under this authority, the Army removed approximately 120,000 people of Japanese ancestry from California, Washington, Oregon and parts of Arizona, giving families as little as 48 hours to dispose of homes, businesses and possessions before being sent first to temporary “assembly centers” and then to one of ten permanent camps in remote inland locations, administered by the newly created War Relocation Authority^[1].

Who Was Affected

Roughly two-thirds of those incarcerated were United States citizens by birth (Nisei); the remainder were first-generation immigrants (Issei) who were legally barred from U.S. citizenship at the time regardless of their conduct or loyalty. No comparable mass detention was imposed on Americans of German or Italian ancestry, despite the United States also being at war with Germany and Italy.

Who Was Responsible

Executive Order 9066 originated with President Roosevelt, urged on by military and political officials including General John L. DeWitt, commander of the Western Defense Command, who publicly argued for removal using explicitly racialized reasoning about the impossibility of distinguishing loyal from disloyal Japanese Americans. The War Relocation Authority (see War Relocation Authority) administered the camps; Congress later funded the program.

The Justification

The government’s official justification was military necessity — the claimed risk of espionage and sabotage by people of Japanese ancestry on the West Coast. The Department of Justice’s own intelligence assessment at the time, the Ringle Report, concluded this risk was minimal and that individualized loyalty review was feasible; this assessment was suppressed from the courts during wartime litigation, a fact that later became central to the 1983 vacation of Fred Korematsu’s conviction.

Ideas Behind the File

The policy reflects national security exceptionalism — extraordinary suspension of ordinary legal protections justified by wartime necessity — compounded by nativism reflected in decades of prior West Coast anti-Japanese political agitation and alien land laws that predated the war.

Institutions

The War Relocation Authority administered the camp system; the War Department’s Western Defense Command carried out the physical removal; the Department of Justice separately operated camps for Japanese, German and Italian nationals classified as “enemy aliens.”

What Is Certain

That approximately 120,000 people were forcibly removed and detained without individualized suspicion or hearing, and that the government’s own wartime intelligence assessment found no evidence supporting the claimed security rationale, are established by federal government records and the 1983 congressional commission’s findings, based on declassified wartime documents^[2].

Human Consequences

Detainees lost homes, farms, businesses and savings, much of it never recovered; families lived for up to three years in barracks-style housing behind barbed wire and guard towers. Long-term effects documented in later research include economic loss carried across generations and significant, well-documented psychological impact on survivors.

Accountability

Individual resisters Fred Korematsu, Gordon Hirabayashi and Minoru Yasui had their wartime convictions vacated in 1983–1986 after historian Peter Irons discovered government records showing the Justice Department had suppressed the Ringle Report and other exculpatory evidence during the original Supreme Court litigation. The 1988 Civil Liberties Act, signed by President Reagan, issued a formal government apology and provided $20,000 in reparations to each of the roughly 82,000 surviving former detainees^[4]. In 2018, the Supreme Court explicitly repudiated its own 1944 Korematsu ruling in Trump v. Hawaii, stating it “was gravely wrong the day it was decided.”

What Changed Afterward

The incarceration and its subsequent repudiation became a central case in U.S. constitutional law regarding the limits of wartime executive power and judicial deference to claimed military necessity, cited in later legal debate over post-9/11 detention policy, and in the continued operation of the Manzanar, Tule Lake and other former camp sites as National Historic Sites administered by the National Park Service.

Sources & Evidence

Last reviewed: January 15, 2025. Found an error? See our corrections policy.