I can't say I agree with any of the major predictions for the next 100 years mentioned in this article, which surmises George Friedman's The Next 100 Years: A Forecast for the 21st Century. Will we ever have another world war? Unlikely. Will Japan attack the US again, I doubt it. Poland and Turkey to become major powers, don't make me laugh.
I agree the US will be a major player ongoing, but China and India have populations of over a billion each, this is a numbers game, it won't happen until near the end of the century, but you bet those guys will be dictating more and more before too long.