I've been thinking about this issue over the last few months. It's beginning to become clear to me that the U.S. can't maintain its "superpower" status forever. As I see it, demographics and economic data bear this out. I believe that, to a large degree, a populous Asia translates into a prosperous Asia at some point in the near future, thus undercutting one leg propping up our "superpower" status. Where, therefore, do we stand? Can or should the U.S. be concerned about losing its status in the world? More beyond the jump.
A few themes have popped up as I've considered this issue:
1.) From what I understand about history (and someone can correct me if I'm wrong), most empires don't die gracefully, rather they seem to lose power fairly quickly (i.e., in a couple of decades). I'm thinking, for instance, of the death of European colonialism in Africa (although European power was already in relative decline). While there's some sort of decline long before the fateful event that marks the "end", generally speaking that final event seems to happen quickly.
2.) The U.S. is (or was, depending on our future presence in Iraq and Afghanistan) largely a landless empire. That's not completely true, we've had episodes of Colonialism in our past (Hawaii and various Pacific islands, for instance). But generally speaking we're an odd "empire", with most our real power being of the "soft" variety (I don't count military power because it doesn't really change people's opinions). I think this is a good thing and somewhat remarkable considering how many quasi-colonial thinkers have had influential positions in U.S. government.
3.) I'm not a big fan of sweeping historical generalizations since they tend to miss the real motivators for change. And they can lead to faulty conclusions (like "The End of History"). So what are the important details, the things that are happening now that could affect how soon the U.S. moves to minor power status?
4.) With respect to point 3, one detail that troubles me is the authoritarian line of thought running through current Republican politics. I hope that it's a temporary hiccup, but I wonder if it's tied somehow to the changing demographics of the U.S. Those changes appear to be driving the immigration debate within their party and, to a lesser extent, in the Democratic party albeit in a different direction. On the Republican side of the aisle the apparent reaction is "make our government more like Apartheid South Africa". On one level that means use government power to enforce a divide between those who've traditionally run things (white Christian males) and those who haven't. On another level it means use military force to prevent demographic changes that you think threaten your way of life. Of course a government of that nature is bad for a whole host of reasons. It's also the kind of government that can deep-six our chances of finding a way to fit into the coming world order where the U.S. isn't the biggest or most important power.
Living in denial of the changing U.S. status in the world will only make the situation worse when it finally dawns on the U.S. population at large that the U.S. is no longer the biggest power in the world. Rather, I think the discussion should start now so that we're ready for that eventuality.