Final answer:
The internment of Japanese Americans during WWII was based on fears of espionage and sabotage, under Executive Order 9066 following the attack on Pearl Harbor. There was no evidence of disloyalty among those interned, and this act was later recognized as a result of racial prejudice and wartime hysteria.
Step-by-step explanation:
The United States' involvement in internment during World War II, specifically the incarceration of Japanese Americans and Japanese immigrants, was driven by the fear that those of Japanese descent on the West Coast might engage in espionage or sabotage aiding Japan against the U.S. Following the attack on Pearl Harbor, Executive Order 9066 authorized the forcible removal and subsequent internment of over 110,000 Japanese Americans and Japanese immigrants, many of whom were children and two-thirds of whom were American citizens. Importantly, internment was enforced despite the absence of evidence indicating these individuals posed a threat to national security, and even as many Japanese Americans demonstrated their loyalty by serving in the U.S. military.
Contrary to some beliefs, the internment did not provide Japanese Americans with employment opportunities nor was it intended to protect them from harm or integrate them into American society. Instead, it was an action fueled by racial prejudice, wartime hysteria, and a failure of political leadership, later acknowledged by the U.S. government as a grave injustice when President Reagan signed an act that apologized for internment and provided reparations to surviving internees.