During WW2, America was at war with Japan, and the Americans thought the Japanese-Americans were loyal to Japan and secret spies, so the internment camps were a way to watch over them.
Many Japanese-Americans were sent to internment camps during WWII. The reason for this was because Japan was one of the United States' major enemies. The U.S. was afraid that some Japanese/Americans may be disloyal to the U.S.
