As this alarming table from Grant's Interest Rate Observer shows, the US government has obligations well in excess of that covered by its non-marketable securities and its bills, notes, and bonds.
*** Included in Grant’s reckoning are some $12.5 trillion in guarantees associated with the housing and financial sectors. A year and a half ago, the dominant view held these guarantees as very unlikely to be called and therefore not really countable against future demands on government resources. In 2008, we know better.
*** The Federal employee and veterans benefits, at $4.7 trillion, also do not appear in the official debt statistics, yet must be paid as surely as the interest on the Treasury bond.
*** Then there's the cavernous future, the deep deep pit, that compromises Social Security, Medicare, and Medicaid obligations.