The USA will eventually fall, as has every great empire before it. I can't see it happening anytime in the near future, but eventually it will. It might not be by barbarians though...it could happen from the inside even...but somehow, one day it will.
(Barbarians is just a comparison) And it may not be in the near future, but I can see it soon. (maybe not in our lifetimes) and by the way, you are right, no superpower really lives on that long.
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