You also have to keep in mind the mood of nation after this attack. The USA lost it's invincibility. At that point in time was by no means assured that the allies would win the war. In fact, we were losing it.
I'd also consider the Red Scare and McCarthyism - fear of Communists used as a proxy to harass and suppress Jews and homosexuals and purge them from society.
Every time the US experiences a test of its values it seems to abandon them immediately. The cultural fear and hatred of the other goes too deep.