Selling or giving armaments to our allies in Europe was not staying out of the war. Have you heard the term "lend-lease"? It was pretty much give, we did not get paid. Look at the numbers for the number of troops we sent. Our participation was not trivial. My parents and other family lived through that period and I was born into a world still dominated by it. My father participated in building the air force (I remember seeing the personal letter to him from Billy Mitchell asking his help). He was part of the air ranger group that flew alongside the black sheep squadron of the marines. I was very aware of how much our nation participated in the second world war. Obviously you are not.