The wealth of the USA is pretty vast. Investment of shares are of foreign interest as well as home interest. I think the Chinese (who will overtake the economy of the US) invest heavily in the stakes of the US dollar and market shares. They recognise that whilst the US is in decline, it simply won't go away within the blink of an eye. The rampant capitalism and stock markets keep its economy afloat. Foreigners can't get enough iphones, Xbox's, and other American exports. Also many American business are leaders in the Internet Market, eg Google, msn, yahoo, Amazon, YouTube, ect. The government may be wasteful, but it's business corporations know what their doing with their expenditure.
Im no big fan of global imperialism either, but its easy to confuse the the end of the beginning with the beginning of the end. The US currently is currently occupying 130 countries from >700 bases; has a bigger army than the rest of the world combined; and the political momentum is all on the far right. On top of that bu$hcos' military adventures were wildly successful despite media reports to the contrary. The american empire isnt going anywhere within the next 30 years and prolly not in the next 300 either.
While it may not be the sole superpower in the near future (China most likely), I believe it will be a superpower for some years to come. It may be argued that the US is currently in a decline but it still has enormous power and probably will for years to come. It may have a struggling economy but militarily and politically it still has impressive influence. However it sadly wont be a superpower forever, if history has taught us anything it is that superpowers don't last forever.
Having Engineering Buddies who work in China 6 months of the year and others that teach science there, China is doing it's utmost to improve itself in all ways, Economical, Environmental and Humanity wise. My friends are loving it there and even I'm learning Mandarin so I can communicate with them, though most of my Chinese friends are excellent at English. No longer can we use the can I Rick the RoRRy jokes. They actually use their tongue properry now, ROR. They are surpassing the US in average Education standards, (probably because they don't have GOP and YEC groups holding them back. Also their leadership is far better educated and policies far more Intelligent and Rational.
If any country will take the leadership of the Globe in the future, it will likely be China.
Where's my Mandarin book, so I will be prepared. :-D~
China is an example of a country that will come to power before the U.S. will. Not only do they basically own us due to our economic debt, but they are also in better shape than us. They don't owe the U.S. trillions of dollars in debt, and according to http://www.theguardian.com/news/datablog/2013/jun/07/china-us-how-superpowers-compare-datablog their unemployment percentage has the advantage. Look at it this way, they have a better economy, higher population, better education, more employed citizens, and with the debt we owe them they will own our country before we know it. Keep in mind this is only one country out of 196 independent countries. The United States is over-powered by China alone, what makes you think that the United States will have Global Superpower in at least 30 years? With our line of presidents we're not getting any better over time. Don't get me wrong, I am proud to be an American, but I don't think we will come to world power, at the very least not in 30 years.