A very interesting read, to be sure. But as a citizen of a country that has been bullied relentlessly by the US, I admit I was a bit angry as I read it. I felt this way because the american empire's position is truly enviable.
For us anti-americans though, there is still hope, it looks as though in the past few years the american people willingly voted away their biggest strength. Bigger than its geography. More and more qualified immigrants are giving the US a 'pass', and with that, the only true creators of value in that country will dwindle in number.
Oh, and of course, China will hasten things.