It's not often you see articles like this in the mainstream press. That in itself I found interesting. http://www.theage.com.au/business/us-is-bankrupt-and-we-dont-even-know-it-20100812-12056.html
Well the last I read Japan and China hold the majority of our debt. Japan has no military and China, I think we still have military superiority over.
The US will stall off the inevitable because of the reserve currency thingy... then they will get inflation. Fractional reserve banking creates way more money than the Fed's "printing presses", once the banks start lending again the money supply will soar. Americans will buy houses and take out loans on the future equity rise and circulate the money...
Do you have any idea how much American currency is floating around? A default would mean hellish devaluation. America would turn into Haiti within weeks. Sounds like a republican dream come true. since Republicans are out to destroy America, a default may very well be what they are planning if they get back into power.
While China is the largest holder on US debt, a significant proportion of US government debt is held by US citizens in the form of US treasuries through retirement funds and the like. So a lot of US citizens would be hurt if the US defaulted. And of course the world economy would collapse overnight. Which is no good for anyone.