Captain, point noted. However, when you say "things" can change quickly, what constitutes "things"? Only then can the disucssion be any meaningful. I am assumging that you are thinking of US hegemony being eroded. However, "hegenmony" is still a pretty vague and subjective term. When the "what" is so subjective, discussions on the "when" is bound to be meaningless. On a related note, I dont think empires collapse suddenly and quickly. First of all, there have not been that many empires to being with - less than 20 significant ones in the last 2 millenia. And these did not collapse suddenly and quickly - but rather declined slowly over the lifetime of several succeeding leaders. Its true that the decline may have been fast compared to the entire time that the empire was in existence, but the decline lasted many decades. Like someone said, i too think that even if chinese per capita gdp eventually exceeds that of the US, it's gonna take several decades (my guess: at least 50 yrs). Also, many ppl didnt anticpate the SU collapse because they had no useful info on which to base their decisions. Info behind the iron curtain tended to stay there. There was no michican consumer sentimetn, or the inflation index, or the unemployment rate, gdp growth rate, balance of trade, or housing price index to really know what was going on in the soviet union. The space (and sputnik) nuclear programs aren't the best indicators of performance. The heads of the politburo knew quite well that they were in dire straits for a few decades.