[Tokra]

Even before declaration of war against us, we were on bad terms with Germany and other Axis powers or their occupied territories. Of course we were cautious of people coming from "threat" countries. Contrary to popular belief, there were numerous acts of sabotage and espionage against us in both WWI and WWII.

You are forgetting that most Americans are (and were in the 1930s and 1940s) of German origin. Much of the espionage and sabotage came from home-grown German-Americans, not immigrants.

Most people think that most Americans are probably of English heritage - but not so. It's German. English runs a close second, with Irish, Italian, Polish & Scottish all in the top ten.

[AmishDude]

Maybe that's so, but espionage was a rare event in the US and even if most espionage acts were done by home-grown German-Americans, the probability of a home-grown German-American committing an act of sabotage is small.