I get concerned when I see this from you.
Like I said, the number that gets reported in the media is that our debt to GDP ratio is about 40% and that we shouldn't be scared until it gets to the 75-80% range. What they never report is, that it's already at the 80% level.
In reality, we have ~$11 trillion of debt and our GDP is ~$14 trillion. Roughly $7 trillion is held by the public: investors like you and me, institutional investors (mutal funds, pensions, etc) and foreign governments. About $4 trillion of the debt is held by our government, which is where the confusion starts. If the government lends to itself, is it really debt?
Social Security has about $4 trillion today but a Present Value liability of roughly $20 trillion. Debt stories that hit the media ignore the unfunded liabilities that are, in effect, on the government's balance sheet. The Treasury estimates the amount of these un/underfunded liabilites to be roughly $45 trillion. So, if you speak about reality, our debt is about 400% of GDP.
My favorite Prof here, a Financial genius, just published a paper comparing the United States to GM. Very interesting read. The problem certainly isn't irreparable, but it is going to be a huge problem to overcome.