It seems to me dead0man is not the smartest guy on this site, for he is not aware "modern alternatives of internment" like those said above could be used with people of different nationalities or ethnicities (including japanese)
but that is obviously not the question being asked. He wanted to discuss what we would do if we were at war with, say, Brazil and what he thought we would do with the Brazillians in the US. He does NOT want to discuss what if Latin America and the US was at war and what we do with all the Latins. From the OP
The United States has a large number of Japanese (or whatever equivalent) nationals who have emigrated from the country we are now at war with and the war is not expected to end quickly. The government has intercepted secret cables detailing an effort by the enemy government to mobilize those immigrants to act as part of their war effort.
Also, and I'm not sure if you're saying there is a one to one comparison here or not, but comparing putting 120,000 almost exclusively innocent Japanese Americans in camps (including children!) to 780 almost exclusively terrorists (or otherwise actively fighting a war against us) in a prison is*, well, dumb.
and no one thinks I'm the smartest guy on the site. I wouldn't want to be the smartest person on the site, they should probably spend their free time better. Also, smart doesn't equal correct.
*yes, I'm aware there are some exceptions to the rule and those are funked up, doesn't change the point though