It was a complex and horrible situation.
The Pearl Harbor Attack was an immediate victory for Japan, but it was ultimately their undoing as well.
In war, in ALL countries, there are ALL KINDS of crazy Theories/Weapons/Tactics that are dreamed up.
The usa had been reading the Japanese Diplomatic codes, and soon after most of the Japan Navy/Military codes as well.
There WAS a plan(s), on paper, to enlist the help of Japanese Americans with different schemes of Invasion/Sabotage on the usa west coast.
This was One Reason for the round-up of The Japanese. Japan had just pulled off a rather brilliant attack at Pearl Harbor...can you imagine what people like Hoover would do with info that "Proved" The Japs were planning to attack the West Coast with the aid of Japanese Americans.?
I think the much bigger crime, than the Japanese being imprisoned, was the way their Property/Business/Homes were often part of a money grab by White America. These people were Stoic/Staunch supporters of The USA...they served with distinction during WWII, were model prisoners, hardly raised a stink about the way they were treated, and we rewarded them by stealing their livelihood from them.
The usa spends WAY Too Much time on The Sins of other Countries/People, and almost NONE on our own.

