I think America is just judged by whether or not we support Israel in the pinch or not. My reading of the Bible looks as though we didn't come to their aid. The same question could be "where is Australia, China, Africa, ect" in end time prophesy? We are the most powerfull nation on Earth at the moment, but will we act, will we continue in power, ect? We could be the most power full country on Earth, but what good is that if we stand by and watch Israel call for help and do nothing?
Yes, the Roman Empire seems to cover most of us as a blanket. That is probably what hangs some people up. they are trying to make distinctions that don’t exist WRT God’s plans.
Our current impostor-in-chief will likely diminish our ultimate significance. (not that Bush did a particularly exemplary job WRT Israel)