A Daily Kos diary about the plan for a new oil currency to replace the $US is interesting and not a little scary.
Americans have little aptitude for the lessons of history, but there's reason to worry that our Washington elite is not handling our imperial moment very well at all.
People forget that almost exactly 100 years ago the British Empire lorded over the Earth nearly as completely as the US does now. While the seeds for future problems were germinating, there's no doubt that every Briton and most everyone else in the world had no inkling that Britain's superpower status would disappear within the next two generations.
After a period of decline, Great Britain has recovered somewhat to be a respectable second-rank power, which isn't that uncommon, Spain has also managed to claw its way back into the ranks of substance, although it had a much longer time it the geopolitical wilderness. Being a continental power, the US has resources enough to avoid complete collapse if it plays its cards right, but history certainly has examples of Great Powers that did lose it all.
I don't think a US decline is inevitable in the near term (over the long term we're all dead and nothing is permanent) but we need to act soon. If the US dollar loses its status as the world currency we're going to have a damned hard time paying for this massive military establishment, for example. It might be wise to look for ways to cut back now, especially if those cutbacks can be tied to arms reduction treaties and other means to keep the numbers of weapons in foreign hands low.