Japanese-American citizens were put into internment camps in the United States because of the Japanese bombing of Pearl Harbor.
On December 7, 1941, the Japanese military attacked a US military base (aka Pearl Harbor). After this attack, president Franklin D. Roosevelt asked Congress to declare war on Japan. Congress did declare war, marking America's entry into World War II.
In the US, president Franklin D. Roosevelt passed Executive Order 9066. This law made it so that all Japanese-American citizens would be put into internment camps. FDR took this action because he was scared of another attack by the Japanese on American soil.
