No, wait!
Listening last night to some WW2 radio stuff about FDR's futile effort to get South America involved on the Allied side. According to the commentators, it didn't work well because Argentina and Chile stubbornly resisted. Well, that's understandable, I thought, since Argentina is heavily Italian and Chile has lots of Germans. The rest of SA is mainly Spanish and Portuguese, both nominally on the Axis side though not belligerent. Not many Brits or Russians in that part of the world, so not much reason for Allied loyalty.
But wait! Doesn't that apply as well to North America? As of 1940, about half of the US had some German genes. Very few Russians. The South was more Irish than English, and Ireland was no friend of England. English blood was common in the Northeast, but Irish and Italian blood were more strongly represented in politics. Most importantly, England was
not seen as our friend. Memories of 1776 and 1812 were still strong, and England had helped the South in Madman Lincoln's war. Everyone remembered what happened when we helped England in 1918: pointless bloodshed that created the conditions for the latest war.
Given all that, it's easy to see why we didn't join until Pearl Harbor.