The cause of the internment

In the days after the bombing of Pearl Harbor, the government of the United States took a series of dramatic steps that resulted in the internment of  approx.  120,000 residents of Japanese ancestry.  What pressures were brought to bear upon various groups and individual decision makers?  What were their primary motivations?  Which constituents prevailed, and why?  In other words, why do you  believe the path toward internment took the  course that it did?

Essay should present a thesis.