How did the Pearl Harbor attack contribute to the internment of Japanese Americans?

The attack on Pearl Harbor served as the primary catalyst for the internment of Japanese Americans by fueling widespread war hysteria and unfounded fears regarding national security.12

Following the December 7, 1941, attack, the U.S. War Department suspected that Japanese Americans might act as saboteurs or espionage agents for Japan. Despite a complete lack of evidence to support these suspicions, the government prioritized perceived national security over the civil liberties of its citizens.31

This atmosphere of suspicion led directly to the signing of Executive Order 9066 by President Franklin D. Roosevelt on February 19, 1942. The order granted the military authority to exclude individuals from designated areas, ultimately resulting in the forced removal and incarceration of approximately 120,000 people of Japanese descent—the majority of whom were U.S. citizens—in detention camps across the American West. A 1982 presidential commission later identified this policy as a failure of leadership driven by racial prejudice and war hysteria.4521