Review of a financial Perpetuity from wikipedia here:
A perpetuity is an annuity that has no end, or a stream of cash payments that continues forever.
Under our current numismatic form of system operations (post 1971), think of the US Treasury's annual stream of USD deposits of taxes/fees/etc received from the non-govt sector which were enabled via the assessment of previous non-govt sector credits originally created via the US Treasury's previous withdrawals of USDs as such a perpetual stream of annual payments, or a Perpetuity, then we can apply the financial formula for the Present Value of a Perpetuity:
PV = A/r
Where A = the period payment, which the US Treasury in FY 2015 received net deposits of $3.9T.
and r is the period interest rate which is what the Fed sets it to; or about 0.25% for the last 8 years.
So dividing the $ 3.9T by the 0.0025 annual rate
= $1.56 x 10^15 or close to $1.6 quadrillion....
A value which the PV of any liability of the US Treasury pales in comparison to, whether Social Security, Medicare or any/all of the above.
This might explain why, from a purely financial perspective, ie leaving out the usual philosophical issue of authority vs. the idiot libertarians, no US Treasury auction ever fails even with all the Peterson morons going all around the place with their dire financial warnings wrt US Treasury liabilities.
The street is obviously not paying any mind to those people our Treasury operations go on everyday like clockwork for 100s of $billions at near zero rates right where the Fed sets them. Rinse and repeat. The Peterson people don't understand any of these systemic operations so hence nobody of import even listens to their bibble babble other than other unqualified idiots like them.
From a purely financial perspective, the issuer (US Treasury) possesses a Perpetuity with a current PV of $1.6 quadrillion which overwhelms any liability of the issuer.