In the immediate aftermath of the Pearl Harbor bombing, the US government retaliated against Japanese immigrants and Japanese American citizens by

Issuing an executive order 9066

Explanation:

The president at the time was franklin roosevelt and this executive order sent Americans of Japanese ancestry into internment camps or what was also known as relocation centers.

There was fear on national security after the bombing. This group was taken to these internment camps because they were seen as a threat and it was feared that they could be used as Agents to carry out further attacks on the US.

answer; the trial de novo