A different time friend a different time...
countries came and went quite easily back then, not so much these days...economies werent interconnected the way they are these days...technology was not what it is these days...
different times, different times....barring WW3 were the US gets wiped off the map...and we all know that wont happen, the US isnt going anywhere sorry jag 
if anything after WW3 we will be even stronger... 
There is absolutely no way you will get stronger. You have been a superpower between 1985 - 2005 and not that you were that powerful but only that you haven't a rival or a competition.
Fact with no evidence yet - sooner or later China will become more economical powerful than the US
Fact with no evidence yet - US will never ever dare to invade Russia or US, because it's a gameover
Fact with no evidence yet - China with help of the US will try to invade Russia that's how the WW3 most probably may have to begin
Fact with no evidence yet - Russia destroys all US cities in an hour time span, your missile shield will not help, but I know you will not believe because you won't be listening to the other perspective.
As tonymctones said things are done different way these days. You ever heard guys the Chimerica word? China and America are so closely interconnected economically between both that there is a new word Chimerica. Again none of you ever dare to touch Russia, to even kiss it without our permission, so China in 2030 the new economical super power and the US is no more like we all have it seen in 2010...