While responding to Fallows article on American power, Yglesias argues that almost all decline is relative:
It’s not just that America is resilient in the face of perceived pitfalls, but so are Switzerland and the Netherlands and everyplace else. The countries that were rich 100 years ago are basically all still the rich countries today. This isn’t an absolute law of nature since there is the case of Argentina, but the point is that it would be really bizarre for the United States to enter a sustained period of decline…The plausible range of future outcomes for the United States is between average living standards being a little bit higher twenty years from now, and average living standards being a lot higher twenty years from now.
The Dish 