Fezzik, I agree that the US is probably not the answer to this question. However, the question is regarding chess history and you have cited only the most recent olympiad and current ratings.
In terms of chess history, how about the fact that Morphy and Fischer were both Americans? They are two of the most dominant chess players of all times in terms of standing out over their peers.
USSR countries have a brilliant track record for chess champs, but which country had the second best history?
You decide and post below!