There are a number of sources of information on what FDR did. I will try to post links in this thread about this issue.
One issue that isn’t widely known is that we knew of many Japanese intelligence operations using emigres via the Magic intercepts. I’m not saying this justifies what was done, that there wasn’t another way of solving the problem, but it makes the whole issue much murkier than we have been led to believe.
Magic: The Untold Story of U.S. Intelligence and the Evacuation of Japanese Residents from the West Coast During WW II
https://www.amazon.com/Magic-Intelligence-Evacuation-Japanese-Residents/dp/0960273611