Considering he went to war in the 40s, I think he would recognize this America. For all of our flaws, we're doing better now than we were then.
Like he said - he fought not because America is great, but because it is fragile. America is not some shining precious jewel, it's a deeply flawed creature - the only thing that marks it as worth saving is the ideal that all people are equal. The further we get from that, the closer we come to being nothing more than trash and a rag.
You might be surprised, there were a lot of pro nazi Americans. The attack on Pearl Harbor changed what might have been a quiet agreement with the new reich