and paid back.
The problem is of course they don't havbe to money to pay the IOU's.
If they were to pay back all the IOU's SS would be fine.
Again, there is nothing to 'pay back'. The IOUs are not written to the Social Security Trust Fund because there is no such beast as a Social Security Trust Fund. The IOUs are written (figuratively) to Social Security recipients, what the government will have to spend on social security payments.
Even if there was a "fund", like some enormous account held by Chase Manhattan into which all SS contributions go, which may be spent
only on Social Security benefits, it will still go broke because the amount being payed out will exceed the amount coming in. It may have already gotten to that point, but it takes awhile for it to bleed dry.
The problem is
not that the government spends the social security contributions on other things. The problem is that there won't be enough social security contributions coming in to sustain the amount that is being paid out, so the balance will have to come from the general fund, eliminating the 'self-supportive' manner of Social Security, unless SS taxes are increased, benefits are reduced, or both. It will always be a slippery slope of one, the other, or both because economically its a bankrupt system.