Final answer:
Franklin Roosevelt signed Executive Order 9066 in 1942 which led to the internment of Japanese Americans during World War II. Over 110,000 individuals, most of whom were citizens, were unjustly relocated to camps without evidence of disloyalty. The U.S. later apologized for this violation of civil liberties.
Step-by-step explanation:
The president who signed the order that established the policy for the internment of Japanese Americans was Franklin Roosevelt. On February 19, 1942, he signed Executive Order 9066, authorizing the Secretary of War and the U.S. Armed Forces to prescribe certain areas as military zones, leading to the relocation of Japanese Americans to internment camps. This action was taken during World War II, after the attack on Pearl Harbor, and affected over 110,000 people of Japanese descent, the majority of whom were American citizens without any evidence of disloyalty to the U.S.
Despite the loyalty shown by many Japanese Americans, including service in the U.S. military, they were forced to endure the prejudice and racism of the time which resulted in their incarceration. Eventually, the U.S. government issued a formal apology and provided reparations for those affected by these internment policies. Notably, the Supreme Court case Korematsu v. United States upheld the actions on the grounds of wartime necessity.