On the recordApril 21, 1999
It creates an obligation to repay because it is taken out in the form of Treasury notes and interest paid, and certainly there is an obligation to pay back. Whether it is an obligation to pay back or a debt, then that is a game of semantics, but it is an obligation. If I had an obligation to pay, as the Government does, to the trust funds of Social Security, I would consider that a debt burden and something I would have to pay. And I am quite sure my accountant would want me to put that in the ``debt'' column of ``bills outstanding'' or ``money to be paid'' or ``owed to'' a particular payment scheme. I call that debt.
Source
govinfo.gov




