Officials in the War Department who advocated the forced removal of Japanese Americans found President Franklin Roosevelt receptive to their cause. On February 19, 1942, Roosevelt signed Executive Order 9066, which set the removal program in motion. The limited official opposition to removal centered in the U.S. Justice Department with officials such as Edward J. Ennis and the FBI's J. Edgar Hoover, who believed it was unconstitutional. Abrogation of the basic constitutional rights of nearly 120,000 Japanese Americans and resident aliens came quickly.

"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

"All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."

The Executive Order 9066 authorized the military to exclude any person from any area of the country where national security was considered threatened. It gave the military broad authority over the civilian population without the imposition of martial law. Although the order did not mention any specific group or recommend detention, its language implied that any citizen might be removed. In practice, the order was applied only to Japanese Americans.

Mary Tsukamoto: Learning of the E.O. (oral history transcript)

Morgan Yamanaka: No Possibility of Resistance (oral history transcript)