Interesting topic and one that I have been thinking about over the last few days. It seems to me that intelligence mostly nurture and not nature. Or, to quote Edison, "What it boils down to is one per cent inspiration and ninety-nine per cent perspiration." Without getting into the whole "Nurture Vs. Nature" argument (both sides are valid, the issue is how you blend the two together), America has an increasing tendency to nurture skills and pursuits that aren't terribly productive. Do a Google news search on the topic of school music programs being neglected and even closed down in favor of the football program.
Someone in this thread mentioned that great geniuses are born and not made; "The cream rises to the top" and "Nature not nurture" are other ways of saying this. The "cream" is anyone who has a natural mental aptitude for some type of thought. That aptitude can be applied to many different disciplines with nearly equal success. However, if a culture is so immersed in vanity and physical pursuits it can drag down those with natural talents or divert them away from an otherwise stellar performance in a certain field.
Anyways, I just found it a bit odd that I should be in agreement with Cheater_1. However, don't count America out just yet... anyone heard of Ray Robson? Maybe not quite Bobby Fischer... not yet anyway.
EDIT: I just say "Anothernewjack's" comment concerning Ray Robson. I see I'm not the only one who's watching Ray...
When a American wants it and is willing to work for it they will have it, why because that's America!