Japanese Americans after the Pearl Harbor attack were removed from their homes against their will and placed in internment camps after Executive Order 9066 was instituted by President Franklin D. Roosevelt, despite heavy resistance from the political system. It was done in the name of national security, since it was assumed that there might be sleeper agents for the Japanese in the U.S.
This was very similar to what was done to German-Americans in both WWI and WWII. After the repeated German submarine attacks, German Americans were labeled "enemy aliens" and place in internment camps. The executive order from FDR also applied to Germans, as well as Italians.
However, the Japanese were treated differently because Japanese people who were American citizens were also apprehended, despite the order originally applying to only enemy aliens, or non-citizens.