...Ultimately the SS trust fund is backed with the "full faith and credit" of the US just as the bonds that are sold to individual investors both here and abroad.
That's not to say they won't cut your benefits if they decide to, just that the fund is a lawful trust fund.
It does exist....
There was a time when a wall separated east and west Berlin. Then one day all the experts where shocked to see it come down.
We have a government which feels it can kill its own citizens overseas without any legal trial and put anyone in jail forever if they simply label them a terrorist. If they can cheat the bond holders of General Motors while enriching their union cronies, you can rest assured they will do as they wish with Social Security.