I would like to open with what I consider to be one of the greatest channels of comfort for me personally, when I am faced with the alarming figures on http://www.usdebtclock.org: Unlike many countries in the Euro-zone (Greece being a prime example), the US issues its debt in the same currency over which it has complete control to mint. For countries that issue debt in this manner, bankruptcy is not just improbable–it is impossible. Unlike many other countries that issue government debt, the US enjoys the ability to issue debt on its own terms, literally in every respect.
China, Japan, and other holders of US debt are forced to purchase the said debt with US Dollars, and not with their own currency. Let me rephrase this: if you want to buy US debt, you need to first trade in your Euros, Yuans, and Yens for United States Dollars. You cannot purchase US debt with anything other than US Dollars, and the US government is not obligated to pay you with anything other than the same US Dollars you used to purchase its treasury securities. In theory, then, China can recall its entire US investments, and the US can, on its own terms, issue (or symbolically “print”) the equivalent dollar amount of those investments. Consequently, the American government enjoys the option of repaying China’s entire $1.16 trillion investment overnight. (Greece does not enjoy that option for the reasons I stated above.)
Of course, there would be a dire consequence to this: massive inflation of the US dollar (as fueled by the issuance of $1.16 trillion in new credit), which in turn would inflate the dollar value of the $1.16 trillion investment China is now getting back. In such a scenario, China would be stabbing itself in the foot by rendering its own investments to be valueless (or valued significantly less), and stabbing itself in the heart by inflating the economy of its biggest export partner. You can imagine the implications this would have on China’s own economy and the economies of all the other foreign holders of US debt.
In short, while the OECD doesn’t like to see a debt-to-GDP ratio of over 90-100% (which is about where we are, with a roughly $15.5 trillion economy and a $16.5 trillion debt) this ratio is less relevant for countries that issue their debt on their own terms and in their own currency. And as for those extra trillions of dollars in debt that are “secret” enough not to be included in my aforementioned $16.5 trillion debt figure: I would remind you to consider that currency derives its value from public perception, and the public doesn’t seem to be caring to perceive any figures beyond $16.5 trillion regardless of how real or not they are. The public cares about accountability, and the “fiscal cliff” showdowns aim to give audiences a veil of accountability while at the same time creating enough political leverage and fear among the public for politicians to achieve unrelated aims under the guise of debt woes.