To keep control of generally a considered enemy such as the Jews during WWII and the Japanese in the U.S. and Canada. Canada had what they lovingly called "camps" in the Interior of B.C. The people were freezing in the winter and frying in the summer. They were given just the necessities in clothing and food and no more. Even though they were Canadian citizens they were considered the enemy and thus they lost their homes and contents in the homes. Unfair? You bet it was! At least they should have put them into more comfortable lodgings in the camps and kept their homes and contents for them to come back too. Just recently the Canadian Gov't had to pay per Japanese person and their children a $17,000 for this treatment. It did nothing to take the nightmarish trauma away and the loss they incurred.